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A Manual of Laboratory and Diagnostic Tests 7th edition (July 2003): By Frances T Fischbach RN, BSN, MSN By
Lippincott Williams & Wilkins Publishers

By OkDoKey

A Manual of Laboratory and Diagnostic Tests
CONTENTS
Editors
Contributors
Dedication
Preface
Acknowledgments

1 Diagnostic Testing
2 Blood Studies; Hematology and Coagulation
3 Urine Studies
4 Stool Studies
5 Cerebrospinal Fluid Studies
6 Chemistry Studies
7 Microbiologic Studies
8 Immunodiagnostic Studies
9 Nuclear Medicine Studies
10 X-Ray Studies
11 Cytologic, Histologic, and Genetic Studies
12 Endoscopic Studies
13 Ultrasound Studies
14 Pulmonary Function, Arterial Blood Gases (ABGs), and Electrolyte Studies
15 Prenatal Diagnosis and Tests of Fetal Well-Being
16 Special Systems, Organ Functions, and Postmortem Studies

Appendix A Standard/Universal Precautions

Appendix B Latex and Rubber Allergy Precautions

Appendix C Sedation and Analgesia Precautions

Appendix D Conversions From Conventional to Systéme International (SI) Units

Appendix E Guidelines for Specimen Transport and Storage

Appendix F Vitamins in Human Nutrition

Appendix G Minerals in Human Nutrition

Appendix H Examples of Forms

Appendix I Panic or Critical Values

Appendix J Effects of the Most Commonly Used Drugs on Frequently Ordered Laboratory Tests (Blood, “Whole” Plasma, Serum, Stool, and Urine)

Appendix K Protocols for Hair, Nails, Saliva, Sputum, and Breath Specimen Collection

Appendix L Protocols for Evidentiary Specimen Collection in Criminal or Forensic Cases

Contributors
Corrinne Strandell, RN, BSN, MSN, PhD
Nursing Research, Home Care and Rehabilitation Specialist, West Allis, WI
Bernice Gestout DeBoer, RN, BSN, CPAN
Parish Nurse, Covenant Health Care, Milwaukee, WI
Mary Pat Haas Schmidt, BS, MT
Manager, Laboratory Services, Pre-insurance testing; Instructor, Medical technology, Waukesha, WI
Jean Schultz, ES, RT, RD, MS
Director of Ultrasound and Radiology Education, St. Luke's Medical Center, Milwaukee, WI
Patricia Pomohac, MT (ASCP)
Supervisor, Diagnostic Immunology, Department of Pathology, United Regional Medical Services, Inc., Milwaukee, WI
Teresa Friedel Abrams, RN, BSN, MSN
Geriatric Nurse Specialist, Menomonee Falls Health Care Center, Menomonee Falls, WI
Carol Colasacco, CT (ASCP), CMIAC
Cytotechnologist, Department of Pathology, Fletcher Allen Health Care, Burlington, VT
Emma Felder, RN, BSN, MSN, PhD
Professor Emeritus, Nursing, University of Wisconsin-Milwaukee, Milwaukee, WI
Ann Shafranski Fischbach, RN, BSN
Occupational Health; Case Manager, Johnson Controls, Milwaukee, WI
Bonnie Grahn, RN, CIC
Infection Control Coordinator, Froedtert Memorial Lutheran Hospital, Milwaukee, WI
Roger Groth
Ophthalmic Technologist, Eye Institute, Froedtert Memorial Lutheran Hospital, Milwaukee, WI
Gary Hoffman
Manager, Laboratory for Newborn Screening, State of Wisconsin, Madison, WI
Karen Kehl, PhD
Assistant Professor-Pathology, Children's Hospital of Wisconsin, Milwaukee, WI
Susan Kirkpatrick, MS
Genetic Counselor, Waisman Center, Madison, WI
Stanley F. Lo, PhD
Assistant Professor-Pathology, Children's Hospital of Wisconsin, Milwaukee, WI
Lynn Mehlberg, ES, CNMT
Director, Quality Assurance-Imaging Department, St. Luke's Medical Center, Milwaukee, WI
Deborah B. Martin, RN, BSN
Community Health Nurse, Baltimore City Health Department, Maternal and Infant Program Field Office, Baltimore, MD
Lorraine Meisner, PhD
Cytogenetics, State Laboratory of Hygiene, Madison, WI
Christine Naczek, MT (ASCP)
Manager, Blood Banking and Pre-Transfusion Testing, Department of Pathology, United Regional Medical Services, Inc.,
Milwaukee, WI
Anne Witkowiak Nezworski, RN, BSN
Maternity and Newborn Specialist, Sacred Heart Hospital, Eau Claire, WI
Joseph Nezworski, ES, RN, BSN
Chief Deputy Medical Examiner, Eau Claire County, Eau Claire, WI
Richard Nuccio, BA, MA, MBA, CNMT, RT (ASCP)
Global Products, General Electric Medical Systems, Milwaukee, WI
Annette O'Gorman, RN, ESN, MSNCS

Family Nurse Practitioner, EM Care S.C., Milwaukee, WI
Tracey Ryan, RD
Chief Clinical Dietitian, Froedtert Memorial Lutheran Hospital, Milwaukee, WI
Julie Saavedra, RN, BA, BSN, CGRN
Nursing Manager, Department of Endoscopy, Rush-Presbyterian-St. Luke's Medical Center, Chicago, IL
John Shalkham
Program Director for School of Cytotechnology, State Laboratory of Hygiene, Clinical Assistant Professor–Department of
Pathology, University of Wisconsin, Madison, WI
Eleanor C. Simms, RNC, BSN
Specialist, Nursing Student Enrichment Program, Coppin State College, Helene Fuld School of Nursing, Baltimore, MD
Nancy A. Staszak, RN, BSN, CCRN
Education Coordinator-QA & Staff Development, Froedtert Memorial Lutheran Hospital, Milwaukee, WI
Frank G. Steffel, BS, CNMT
Program Director-Nuclear Medicine Technology, Department of Radiology, Froedtert Memorial Lutheran Hospital,
Milwaukee, WI
Rosalie Wilson Steiner, RN, BSN, MSN, PhD
Community Health Specialist, Milwaukee, WI
Thudung Tieu
QA/Safety Coordinator, United Dynacare Laboratories, Milwaukee, WI
Jean M. Trione, RPh
Clinical Specialist, Wausau Hospital, Wausau, WI
Beverly Wheeler, RN, BSN, MSN, CS
Cardiology; Cardiothoracic Nurse Specialistm, National Naval Medical Center, Bethesda, MD
Michael Zacharisen, MD
Assistant Professor-Pediatrics, Children's Hospital of Wisconsin, Milwaukee, WI

DEDICATION
To Michael, Mary, Paul, and Margaret

EDITORS
FRANCES TALASKA FISCHBACH, RN, BSN, MSN
Associate Clinical Professor of Nursing
Department of Health Restoration
School of Nursing
University of Wisconsin-Milwaukee
Milwaukee, Wisconsin; Associate Professor of Nursing (Ret)
School of Nursing
University of Wisconsin-Milwaukee
Milwaukee, Wisconsin
MARSHALL BARNETT DUNNING, III, BS, MS, PHD
Associate Professor of Medicine
Department of Medicine
Division of Pulmonary/Critical Care Medicine
Medical College of Wisconsin, Milwaukee
Wisconsin; Director
Pulmonary Diagnostic Laboratory
Froedtert Memorial Lutheran Hospital
Milwaukee, Wisconsin
QUINCY MCDONALD
Acquisitions Editor
SHARON NOWAK/MARIE RIM
Editorial Assistant
DEBRA SCHIFF
Senior Production Editor
HELEN EWAN
Senior Production Manager
ERIKA KORS
Managing Editor / Production
CAROLYN O'BRIEN
Art Director
BJ CRIM
Design
WILLIAM ALBERTI
Manufacturing Manager
ALEXANDRA NICKERSON
Indexer

PREFACE
PURPOSE
The purpose of A Manual of Laboratory and Diagnostic Tests, in this Seventh edition, is to promote the delivery of safe,
effective, and informed care for patients undergoing diagnostic tests and procedures and also to provide the clinician and
student with a unique resource. This comprehensive manual provides a foundation for understanding the relatively
simple to the most highly complex diagnostic tests that are delivered to varied populations in varied settings. It describes
the clinician's role in providing effective diagnostic services in depth, through affording the necessary information for
quality care planning, individualized patient assessment, analysis of patient needs, appropriate interventions, patient
education, patient follow-up, and timely outcome evaluation.
Potential risks and complications of diagnostic testing mandate that proper test protocols, interfering factors, follow-up
testing, and collaboration among those involved in the testing process be a significant part of the information included in
this text.

ORGANIZATION
This book is organized into 16 chapters and 12 appendices. Chapter 1 outlines the clinician's role in diagnostic testing
and includes interventions for safe, effective, informed pre-, intra-, and posttest care. This chapter includes a Patient's
Bill of Rights and Responsibilities, a model for the role of the clinical team in providing diagnostic care and services, test
environments, reimbursement for diagnostic services, and the importance of communication as key to desired outcomes.
The intratest section is expanded to include information about collaborative approaches facilitating family presence
during invasive procedures, risk management, the collection, handling, and transport of specimens, infection control,
controlling pain, comfort measures, administration of drugs and solutions, monitoring fluid intake and loss, using required
equipment kits and supplies, properly positioning the patient for the procedure, managing the environment, and patient
monitoring. The reader is referred back to Chapter 1, Diagnostic Testing, throughout the text for information about the
clinician's role and diagnostic services. Chapter 2, Chapter 3, Chapter 4, Chapter 5, Chapter 6, Chapter 7, Chapter 8,
Chapter 9, Chapter 10, Chapter 11, Chapter 12, Chapter 13, Chapter 14, Chapter 15 and Chapter 16 focus upon specific
categories that include:
Chapter 2: Blood Studies
Chapter 3: Urine Studies
Chapter 4: Stool Studies
Chapter 5: Cerebrospinal Fluid Studies
Chapter 6: Chemistry Studies
Chapter 7: Microbiologic Studies
Chapter 8: Immunodiagnostic Studies
Chapter 9: Nuclear Medicine Studies
Chapter 10: X-ray Studies
Chapter 11: Cytology, Histology, and Genetic Studies
Chapter 12: Endoscopic Studies
Chapter 13: Ultrasound Studies
Chapter 14: Pulmonary Function and Blood Gas Studies
Chapter 15: Prenatal Diagnosis and Tests of Fetal Well-Being
Chapter 16: Special Systems, Organ Functions, and Postmortem Studies

CHAPTER CONTENT AND FEATURES
Background rationale
Test purpose
Interfering factors
Description of the procedure protocol and time frames and test completion
Reference ranges and normal values, expectations
Patient involvement (eg, history of signs and symptoms, body position, breathing instructions, electrode placement,
compliance issues, patient right to refuse testing)
Method of specimen collection (biohazard guidelines), handling, and transportation
Clinical implications with interpretation of abnormal findings, unexpected outcomes, and disease patterns
Interventions for pretest patient preparation (medications, fasting), explanation of benefits and risks, intratest
patient care (appropriate monitoring, conscious sedation), and posttest patient aftercare (includes monitoring,
explanation of further testing and treatment modalities)
Special features integrated into the format include:
The clinician's role in providing diagnostic services.
Clinical Alerts and Education Alerts that signal special cautions.
Specific guidelines listed for each test phase.
Expected outcomes with evidence-based patient expectations and reference ranges as defined by the specialty.
A user-friendly format of the text to support easy information retrieval.
Both conventional and SI units are listed and, where possible, age-related reference values are also listed as a

component of normal reference values.
Numerous examples of test values and clinical considerations for newborn, infant, child, adolescent, and older adult
groups where appropriate.
A bibliography at the end of each chapter representing a composite of selected references from various disciplines
and directs the clinician to information available beyond the scope of this book.
Extensive appendices providing the clinician with additional data for everyday practice.
Current, complete, and accurate content, which has been compiled from various multidisciplinary sources, then
carefully scrutinized and continually reevaluated.

NEW INFORMATION IN THE SEVENTH EDITION
The addition of many new tests and methodologies includes:
Newborn screening for inherited disease
Updated Pap smears and protocols for further testing
Cytokines
Metabolic autopsy
Tissue (histology) biopsies and predictive markers for treatment response
Tests for bone disease
Tests for heart disease, congestive and acute MI disease
Microbiological testing, bioterrorism agents, detecting food poisoning, anthrax, plague, and hemorrhagic fever
Breast diagnostic and prognostic markers
Fetal predictive tests of abnormal development
Breath tests for ulcers, alcohol, lactose, etc.
Fertility tests
Expanded scope of magnetic resonance (MRI) scans
Expanded scope of sleep/sleepiness studies in newborns, children, older adults
New nuclear tumor and infection scans
PET scans combined with CT spiral imaging and ultrasound
Ductal lavage for determining Gail Index for breast cancer risk
New sentinel node localization
LEEP GYN procedure
Eye tests for retinal disorders, macular degeneration, visual acuity, and glaucoma
Expanded content on keeping records of diagnostic tests, use of proper forms, and standardized patient reports
Panels of multiple tests (e.g., metabolic syndrome, syndrome X) within Chapter 6 Chemistry Tests
The appendices are completely revised and contain many additions. For example, Appendix D offers information
regarding collection of saliva, breath, nail, sputum, and hair specimens. Appendix H provides examples of commonly
used forms and infrequently used forms (videotaping, refusal). Appendix L deals with guidelines for collecting evidentiary
specimens.
Revised chapters include changes in the clinician's role and reflect current laboratory and diagnostic practice standards.
Throughout the text, a greater emphasis is placed upon communication skills and collaboration between patients, their
significant others, and health professionals from diverse disciplines. When clinicians see patients in the context of what
the patient and loved ones are experiencing (ie, situational needs, expectations, previous experiences, and the
environment in which they live), only then can they offer meaningful support and care. When patients believe the clinician
is on their side, they have an increased sense of control. Identifying with the patient's point of view leads to a more
profound level of communication.

CURRENT DEVELOPMENTS IN LABORATORY AND DIAGNOSTIC TESTING
New technologies foster new scientific modalities for patient assessment and clinical interventions. Thus, the clinician is
provided a greater understanding of the long chain of events from diagnosis through treatment and outcomes. In a brief
span of years, new technologies have introduced greatly improved developments in total body and brain x-ray scanners;
digital and enhanced imaging; magnetic resonance (MR); positron emission tomography (PET) scanners, combination
scans such as PET and CT to diagnose cancer and infections; greatly enhanced ultrasound and nuclear medicine
procedures; genetic mutation studies; new tests for cancer; new cancer markers for diagnosis and prognosis; sleep
disorders tests; technology for fetal testing before birth, and postmortem testing after death. Many new technologies are
faster, more patient-friendly, more comfortable, and provide an equivalent or higher degree of accuracy (ie, HIV or
hepatitis detection, monitoring for drug abuse or managing therapeutic drug levels). Saliva and breath testing is gaining
ground as a mirror of body function and emotional, hormonal, immune, and neurologic status, as well as providing clues
about faulty metabolism. Noninvasive and minimally invasive testing, (ie, need only one drop of blood, nail and hair
clippings), which is better suited for testing in environments such as the workplace, private home, and other
nontraditional health care settings such as churches, is made possible by better collection methods and standardized
collection techniques. Newest diagnostic lab technologies include hand-held nucleic acid detectors for specific bacteria
and viruses, hand-held miniaturized chip-based DNA analyzers, reagentless diagnostics that introduce the sample (hand,
finger, ear lobe, etc.) to magnetic fields, and magnetic resonance spectroscopy (MRS). Non-invasive and minimally
invasive diagnostics include infrared light to estimate glucose, rapid oral screen for HIV, proteinomics, functional and
molecular techniques. Managed care and its drive for control of costs for diagnostic services exerts a tremendous effect
on consumers' ability to access testing services care. This results in mixed access to services, depending upon approval
or denial of coverage.

A resurgence in the use of traditional, trusted diagnostic modalities, such as electroencephalogram (EEG), is being seen
in certain areas. Diseases such as HIV, antibiotic-resistant strains of pathological organisms, and Type 2 diabetes are
becoming more prevalent. In the workplace, thorough diagnostic testing is more common as applications are made for
disability benefits. Also, requirements for periodic monitoring of exposures to potentially hazardous workplace
substances (chemicals, heavy metals), breathing and hearing tests, and TB and latex allergy testing requires skill in
administering and procuring specimens. The number of forensic DNA tests being performed has increased tremendously.
Concurrently, consumer perceptions have shifted from implicit faith in the health care system to concerns regarding less
control over choices for health care and more distrust of the system in general.
These trends—combined with a shift in diagnostic care from acute care hospital settings to outpatient departments,
physicians' offices, clinics, community-based centers, nursing homes, and sometimes even churches, stores and
pharmacies—challenge clinicians to provide standards-based, safe, effective, and informed care. Because the health
care system is becoming a community-based model, the clinician's role is also changing. Updated knowledge and skills,
flexibility, and a heightened awareness of the testing environment (point of care testing) are needed to provide diagnostic
services in these settings.
Clinicians must also adapt their practice to changes in other areas. This includes developing, coordinating, and following
policies and standards set forth by institutions, governmental bodies, and regulatory agencies. Being informed regarding
ethical and legal implications of such things as informed consent, privacy, patient safety, the right to refuse tests,
end-of-life decisions, and trends in diagnostic research procedures add another dimension to the clinician's
accountability and responsibility. The consequences of certain types of testing (ie, HIV and genetic) and the implications
of confidential versus anonymous testing must also be kept in mind. For example, anonymous tests do not require the
individual to give his or her name, whereas confidential tests do require the name. This difference has implications in the
requirements and process of agency reporting all patients as well as for select groups of infectious diseases such as HIV.
Responding to these trends, the Seventh edition of A Manual of Laboratory and Diagnostic Tests is a comprehensive,
up-to-date diagnostic reference source that includes information about newer technologies, together with the
time-honored classic tests that continue to be an important component of diagnostic work. It meets the needs of
clinicians, educators, researches, students, and others whose work and study requires this type of resource or reference
manual.
Frances Talaska Fischbach

ACKNOWLEDGMENTS
It is with sincere gratitude and pleasure that I acknowledge the collaboration of Dr. Marshall B. Dunning for his diligence,
extra effort, and graciousness in accomplishing the task of renewal and enhancement for the revision of this text, for the
7th edition, all in a timely manner.
I want to give special praise and recognition to my husband, Jack Fischbach, the best researcher I have ever had; to
Corrinne Strandell, Mary Pat Schmidt, Bernice DeBoer, Pat Pomohac, and Jean Schultz for their dedication, kindness,
support, and generous help in manuscript preparation; to Kathie Gordon, Kathleen Dunning, Deanne Shmitz, and
Margaret Fischbach, for carefully arranging, organizing, and typing the manuscript.
I would also like to acknowledge and thank all the reviewers, researchers, and consultants who provided ideas for
manuscript revision and whose comments to me have helped make the book better. This work would not have been
complete without the help and information provided by the librarians and staff of the Todd Wehr Library of the Medical
College of Wisconsin, the Marquette University Library, and St. Joseph's Hospital Library; with thanks to Dynacare
Laboratories and Medical Science Laboratories, especially for referencing their Laboratory Handbooks, and to the
Infection Control Staff, Neuroscience Center, Transplant Services, Transfusion Services, Eye Institute, at Froedtert
Memorial Hospital of Milwaukee, Wisconsin.
Appreciation and recognition are also due these persons who helped with this and previous editions: my daughters, Mary
Fischbach Johnson, BS, MS Ed, and Margaret Fischbach, BA, JD; my son-in-law, Richard Johnson, BA; my
daughter-in-law, Ann Shafranski Fischbach, BSN; and the hard work on this edition and in the past of the entire staff at
Lippincott Williams & Wilkins, especially Sharon Nowak, Marie Rim, Quincy McDonald, Debra Schiff, Kim Lilly, Kathie
Barrie, and, as always, Jay Lippincott. Writing a book is truly a labor of love, and the process makes me humble and
thankful to many, many individuals, named and unnamed, who have made it possible. Thanks for a job well done.
Frances Fischbach

1 Diagnostic Testing
A Manual of Laboratory and Diagnostic Tests

1
Diagnostic Testing
OVERVIEW OF THE CLINICIAN'S ROLE: RESPONSIBILITIES, STANDARDS, AND REQUISITE KNOWLEDGE
Education Alert
Chart 1.1 Grading Guidelines for Scientific Evidence
Chart 1.2 Basics of Informed Care
PRETEST PHASE: ELEMENTS OF SAFE, EFFECTIVE, INFORMED CARE
Basic Knowledge and Necessary Skills
Testing Environments
History and Assessment
Reimbursement for Diagnostic Services
Chart 1.3 Tests Covered by Most Insurance Carriers
Methodology of Testing
Interfering Factors
Avoiding Errors
Proper Preparation
Patient Education
Testing Protocols
Patient Independence
Test Results
Laboratory Reports
Margins of Error
Ethics and the Law
Patient's Bill of Rights and Patient Responsibilities
Cultural Sensitivity
INTRATEST PHASE: ELEMENTS OF SAFE, EFFECTIVE, INFORMED CARE
Basic Knowledge and Required Skills
Infection Control
NOTE
Collaborative Approaches
Risk Management
Specimens and Procedures
Equipment and Supplies
Family Presence
Positioning for Procedures
Administration of Drugs and Solutions
Management of Environment
Pain Control, Comfort Measures, and Patient Monitoring
POSTTEST PHASE: ELEMENTS OF SAFE, EFFECTIVE, INFORMED CARE
Basic Knowledge and Necessary Skills
Abnormal Test Results
Clinical Alert
Follow-Up Counseling
Monitoring for Complications
Test Result Availability
Clinical Alert
Referral and Treatment
Follow-Up Care
Documentation, Record Keeping, and Reporting
Chart 1.4 Diseases and Conditions Reportable by Health Care Providers and Others
Chart 1.5 Diseases and Conditions Reportable by Laboratory Directors
Guidelines for Disclosure
Patient Responses to Expected or Unexpected Outcomes
Expected and Unexpected Outcomes
IMPORTANCE OF COMMUNICATION
CONCLUSION
BIBLIOGRAPHY

OVERVIEW OF THE CLINICIAN'S ROLE: RESPONSIBILITIES, STANDARDS, AND REQUISITE
KNOWLEDGE
In this era of high technology, health care delivery involves many different disciplines and specialties. Consequently,
clinicians must have an understanding and working knowledge of modalities other than their own area of expertise. This
includes diagnostic evaluation and diagnostic services. Laboratory and diagnostic tests are tools to gain additional
information about the patient. By themselves, these tests are not therapeutic; however, when used in conjunction with a
thorough history and physical examination, these tests may confirm a diagnosis or provide valuable information about a
patient's status and response to therapy that may not be apparent from the history and physical examination alone.
Generally, a tiered approach to selecting tests is used:
1.
2.
3.
4.

Basic screening (frequently used with wellness groups and case finding)
Establishing (initial) diagnoses
Differential diagnosis
Evaluating current medical case management and outcomes

5.
6.
7.
8.
9.

Evaluating disease severity
Monitoring course of illness and response to treatment
Group and panel testing
Regularly scheduled screening tests as part of ongoing care
Testing related to specific events, certain signs and symptoms, or other exceptional situations (eg, infection and
inflammation [bladder infection or cellulitis], sexual assault, drug screening, pheochromocytoma, postmortem tests,
to name a few) ( Table 1.1)
Table 1.1 Examples of Selecting Tests
Diagnostic Test

Indication

Stool occult blood
Serum potassium

Yearly screening after 45 years of age
Yearly in patients on diuretic agents or potassium supplements; in cases of
some cardiac arrhythmias
Monitoring patient on hepatotoxic drugs; establish baseline values
In the presence of abdominal pain, suspect pancreatitis
Suspicion of hypothyroidism, hyperthyroidism, or thyroid dysfunction, 50 years
of age and older
In sexually active persons with multiple partners to monitor for pelvic
inflammatory disease
Baseline study; abnormal bleeding; detection of anemia (use CBC results if they
are recent)
Yearly for all women = 18 years of age; more often with high-risk factors (eg,
dysplasia, human immunodeficiency virus [HIV], herpes simplex) now checks for
human papillomavirus (HPV), chlamydia, and gonorrhea, using DNA
Pyuria
Positive rapid plasma reagin (RPR) test result

Liver enzyme levels
Serum amylase
Thyroid-stimulating hormone
(TSH) test
Chlamydia and gonorrhea
Hematocrit and hemoglobin
Papanicolaou cervical smear
(Pap)
Urine culture
Syphilis serum fluorescent
treponemal antibody (FTA) test
Tuberculosis (TB) skin test
Fasting blood glucose (FBG)
Urinalysis (UA)
Prothrombin time (PT) (INR)
Prostate-specific antigen (PSA)
and digital rectal examination
Chest x-ray

Easiest test to use for TB screening of individuals < 35 years of age or those
with history of negative TB skin tests, for persons in resident homes
Every 3 years starting at 45 years of age; monitor diabetes control
Signs or history of recurrent urinary tract disease; pregnant women; men with
prostatic hypertrophy
Monitoring anticoagulant treatment
Screen men = 50 years of age for prostate cancer yearly

Monitor for lung lesions and infiltrates; congestive heart failure; anatomic
deformities, posttrauma, before surgery, follow-up for positive TB skin test and
monitor treatment
Mammogram
Screen by 40 years of age in women, then every 12–18 months between 40 and
49 years of age, annually = 50 years of age; follow-up for history and treatment
of breast cancer; routine screening when strong family history of breast
carcinoma
Colon x-rays and
Screen adults for colon cancer beginning at age 45; follow up for presence of
proctosigmoidoscopy
hemoglobin- or guaiac-positive stools, polyps, diverticulosis
Computed tomography (CT)
Before and after treatment for certain cancers, injuries, illness (eg, suspected
scans
transient ischemic attack, cerebro-vascular accident; diagnostic evaluation of
certain signs/symptoms)
DNA testing of hair, blood, skin
To gather postmortem evidence, in certain criminal cases; to establish identity
tissue, or semen samples
and parentage
Some tests are mandated by government agencies or clinical practice guidelines of professional societies; others
are deemed part of necessary care based on the individual practitioner's judgment and expertise or a group
practitioner consensus. There is not a consensus as to the frequency of testing (eg, annually or after a certain
age).

Test selections are based on subjective clinical judgment. Often diagnostic tests or procedures are used as predictors of
surgical risk and/or morbidity and mortality rates (eg, maximum oxygen consumption determination to assess risk before
esophageal cancer surgery) as the risk may outweigh the benefit. Use of evidence-based guidelines for scheduling,
selecting, retaining, or eliminating certain diagnostic tests may help in more effective case management and cost
containment. These guidelines use a system that grades the quality of scientific evidence based on published reports of
clinical trials, expert consensus, or clinical expertise. Levels of evidence are A to C and E, with A being the best evidence
and E referring to expert opinion or consensus ( Chart 1.1).

Education Alert
Not all information on the Internet is reliable.

Chart 1.1 Grading Guidelines for Scientific Evidence

A. Clear evidence from all appropriately
conducted trials
B. Supportive evidence from well-conducted
studies or registries
C. No published evidence; or only case,
observational, or historical evidence
D. Expert consensus or clinical experience or
Internet polls

A. Measure plasma glucose through an accredited lab to diagnose
or screen for diabetes
B. Draw fasting blood plasma specimens for glucose analysis
C. Self-monitoring of blood glucose may help to achieve better
control
D. Measure ketones in urine or blood to monitor and diagnose
diabetic ketoacidosis (DKA) (in home or clinic)

As an integral part of their practice, clinicians have long supported patients and their significant others in meeting the
demands and challenges incumbent in the simplest to the most complex diagnostic testing. This testing begins before
birth and frequently continues after death. The clinician who provides diagnostic services must have basic requisite
knowledge to plan patient care and an understanding of psychoneuroimmunology (effects of stress on health status),
must make careful judgments, and must gather vital information about the patient and the testing process, to diagnose
appropriately within the parameters of the clinician's professional standards ( Table 1.2; Chart 1.2).

Table 1.2 Examples of Inappropriate Tests and Replacement Tests
Inappropriate

Replacement

Prostatic acid phosphatase
PSA or free PSA
Ammonia
AST, GGT
Crossmatch (needed if blood is actually to be given)
Type and screen
Calcium
Ionized calcium
CBC
Hemogram
HCV antibody
HCV RNA by PCR
Iron
Ferritin
Lupus cell
ANA
Creatinine
Urea
CRP
ESR
PSA, prostate-specific antigen; AST, aspartate transaminase; GGT, gamma-glutamyltransferase; CBC, complete blood
count; HCV, hepatitis C virus; PCP, polymerase chain reaction; ANA, antinuclear antibody; CRP, C-reactive protein;
ESR, erythrocyte sedimentation rate.

Chart 1.2 Basics of Informed Care
Manage testing environment using collaborative approach
Communicate effectively and clearly
Prepare the patient properly
Follow standards
Consider culture, gender, and age diversity
Measure and evaluate outcomes; modify treatment as necessary
Manage effective diagnostic services using team approach
Interpret, treat, monitor, and counsel about abnormal test outcomes
Maintain proper test records
The diagnostic testing model incorporates three phases: pretest, intratest, and posttest ( Fig. 1.1). The clinical team
actively interacts with the patient and his or her significant others throughout each phase. The following components are
included with each laboratory or diagnostic test in this text:

FIGURE 1.1 Model* for the role** of the clinical team in diagnostic care*** and services.****

Pretest Interventions:
1. Test background
information
2. Normal (reference
values)
3. Explanation of test
4. Indications for testing

Intratest Interventions:
1. Actual description of procedures
2. Specimen collection and transport
3. Clinical implications of abnormal
results
4. Interfering factors

Posttest Interventions:
1. Patient aftercare
2. Clinical, education, and procedure
alerts
3. Special cautions
4. Interpretation of test results

Each phase of testing requires that a specific set of guidelines and standards be followed for accurate, optimal test
results. Patient care standards and standards of professional practice are key points in developing a collaborative
approach to patient care during diagnostic evaluation. Standards of care provide clinical guidelines and set minimum
requirements for professional practice and patient care. They protect the public against less-than-quality care ( Table
1.3).

Table 1.3 Standards for Diagnostic Evaluation
Source of Standards for
Diagnostic Service

Standards for Diagnostic Testing

Examples of Applied Standards for
Diagnostic Testing

Professional practice parameters of
American Nurses Association
(ANA), American Medical
Association (AMA), American
Society of Clinical Pathologists
(ASCP), American College of
Radiology, Centers for Disease
Control and Prevention (CDC),
JCAHO health care practice
requirements
The guidelines of the major
agencies, such as American Heart
Association, Cancer Society, and
American Diabetes Association

Use a model as a framework for choosing
the proper test or procedure and in the
interpretation of test results. Use
laboratory and diagnostic procedures for
screening, differential diagnoses,
follow-up, and case management.

Test strategies include single tests or
combinations/ panels of tests. Panels
can be performed in parallel, series, or
both.

Order the correct test, appropriately collect
and transport specimens. Properly perform
tests in an accredited laboratory or
diagnostic facility. Accurately report test
results. Communicate and interpret test
findings. Treat or monitor the disease and
the course of therapy. Provide diagnosis
as well as prognosis.
Individual agency and institution
Observe standard precautions (formerly
policies and procedures and
known as universal precautions). Use
quality-control criteria for specimen latex allergy protocols and required
collection, procedure statement for methodology of specimen collection. Use
monitoring the patient after an
standards and statements for monitoring
invasive procedure, and policy for
patients who receive conscious sedation
universal witnessed consent
and analgesia. Vital signs are monitored
situations. Statements on quality
and recorded at specific times before and
improvement standards. Use
after the procedure. Patients are
standards of professional practice
monitored for bleeding and respiratory or
and standards of patient care. Use neurovascular changes. Record data
policy for obtaining informed
regarding outcomes when defined care
consent/witnessed consent. Use
criteria are implemented and practiced.
policies for unusual situations.
Protocols to obtain appropriate consents
are employed, and deviations from basic
consent policies are documented and
reported to the proper individual.

Patients receive diagnostic services
based on a documented assessment of
need for diagnostic evaluation. Patients
have the right to necessary information,
benefits, or rights, to enable them to
make choices and decisions that reflect
their need or wish for diagnostic care.
The clinician wears protective eyewear
and gloves when handling all body fluids
and employs proper handwashing
before and after handling specimens
and between patient contacts. Labeled
biohazard bags are used for specimen
transport. Vital signs are monitored and
recorded at specific times before and
after the procedure. Patients are
monitored for bleeding and respiratory
or neurovascular changes. Record data
regarding outcomes when defined care
criteria are implemented and practiced.
Protocols to obtain appropriate consents
are employed, and deviations from basic
consent policies are documented and
reported to the proper individual.

State and federal government
communicable disease reporting
regulations; Centers for Disease
Control and Prevention (CDC), U.S.
Department of Health and Human
Services, Agency for Health Care
Policy and Research (AHCPR), and
Clinical Laboratory Improvement Act
(CLIA)

Clinical laboratory personnel and other
health care providers follow regulations to
control the spread of communicable
diseases by reporting certain disease
conditions, outbreaks, and unusual
manifestations, morbidity, and mortality
data. Findings from research studies
provide health care policy makers with
evidence-based guidelines for appropriate
selection of tests and procedures.

The clinician reports laboratory
evidence of certain disease classes (eg,
sexually transmitted diseases,
diphtheria, Lyme disease, symptomatic
HIV infection; see list of reportable
diseases). Personnel with hepatitis A
may not handle food or care for patients,
young children, or the elderly for a
specific period of time. Federal
government regulates shipment of
diagnostic specimens. MR and CT are
used to evaluate persistent low back
pain according to AHCPR guidelines.
U.S. Department of Transportation Alcohol testing is done in emergency
Properly trained personnel perform
rooms in special situations (eg, following a blood, saliva, and breath alcohol testing
motor vehicle accident, homicide, or
and use required kits as referenced by
suicide, or an unconscious individual).
federal law.
Occupational Safety and Health
Workplace testing
The clinician is properly trained, under
Administration (OSHA)
mandated guidelines, to administer
employee medical surveillance and
respirator qualification and fit testing.
JCAHO, Joint Commission on Accreditation of Healthcare Organizations; HIV, human immunodeficiency virus; MR,
magnetic resonance; CT, computed tomography.

If test results are inconclusive or negative and no definitive medical diagnosis can be established, other tests and
procedures may be ordered. Thus, testing can become an involved and lengthy process (see Fig. 1.1).
Understanding the basics of safe, effective, and informed care is important. These basics include assessing risk factors
and modifying care accordingly, using a collaborative approach, following proper guidelines for procedures and specimen
collection, and delivering appropriate care throughout the process. Providing reassurance and support to the patient and
his or her significant others, intervening appropriately, and clearly documenting patient teaching, observations, and
outcomes during the entire process are important (see Fig. 1.1).
A risk assessment before testing identifies risk-prone patients and helps to prevent complications. The following factors
increase a patient's risk for complications and may affect test outcomes:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.

Age > 70 years
History of falls
History of serious chronic illnesses
History of allergies (eg, latex, contrast iodine, radiopharmaceuticals, and other medications)
Infection or increased risk for infection (eg, human immunodeficiency virus [HIV], organ transplantation,
chemotherapy, radiation therapy)
Aggressive or antisocial behavior
Seizure disorders
Uncontrolled pain
Gastric motility dysfunction
Use of assistive devices for activities of daily living (ADLs)
Unsteady gait, balance problems
Neuromuscular conditions
Weakness, fatigability
Paresthesias
Impaired judgment or illogical thinking
Severe visual problems
Hearing impairment
Use of diuretics, sedatives, analgesics, or other prescription or over-the-counter (OTC) drugs
Alcohol or illegal drug use or addiction

The environments in which diagnostic services are provided, the degree of cultural diversity present in the community,
and the physical, emotional, social, and spiritual state of the patient all influence the patient's response to the procedure.
Including the patient's significant others is a vital component of the entire process and must not be taken lightly or
casually dismissed.
Testing environments vary. Certain tests (eg, cholesterol screening, blood glucose, electrocardiogram [ECG], lipid
profiles, tuberculosis [TB] skin tests) can be done “in the field,” meaning that the service is brought to the patient's
environment. Other tests (eg, x-rays using contrast media and those that require special patient preparation, invasive
procedures, nuclear medicine procedures, hormone levels, and 24-hour urine testing panels) must be done in a
physician's office, clinic, or hospital setting. Magnetic resonance (MR) imaging and ultrasound procedures (eg,
echocardiograms) are commonly performed in freestanding or specialty diagnostic centers. Complex tests such as
endoscopic retrograde cholangiopancreatography (ERCP), cardiac catheterization, or bronchoscopy may require hospital
admission or at least outpatient status. As testing equipment becomes more technologically sophisticated and risks
associated with testing are reduced, the environment in which diagnostic procedures take place will also shift. Insurance
reimbursement for testing also influences trends. Managed care and case management, together with collaboration
among the diverse health care disciplines and the patient, are key factors in determining how and to what degree optimal

diagnostic services are used. Clear, timely, accurate communication among all patients and professionals is key to
minimizing problems and frustrations.
As societies become more culturally blended, the need to appreciate and work within the realm of cultural diversity
becomes imperative. Interacting with patients and directing them through diagnostic testing can present certain
challenges if one is not familiar and sensitive to the health care belief system of the patient and his or her significant
others. Something as basic as attempting to communicate in the face of language differences may necessitate
arrangements for a relative or translator to be present during all phases of the process. Special attention and
communication skills are necessary for these situations as well as when caring for children and for comatose, confused,
or frail patients. Consideration of these issues will significantly influence compliance, outcomes, and positive responses
to the procedure. To be most effective, professional care providers must be open to a holistic perspective and attitude
that affects their care giving, communication, and patient-empowering behaviors. Clinicians who understand the patient's
basic needs and expectations and strive to accommodate those as much as possible are truly acting as patient
advocates.
Preparing patients for diagnostic or therapeutic procedures, collecting specimens, carrying out and assisting with
procedures, and providing follow-up care have long been requisite activities of professional practice. This care may
continue even after the patient's death. Diagnostic postmortem services include death reporting, possible postmortem
investigations, and sensitive communication with grieving families and significant others regarding autopsies,
unexplained death, other postmortem testing, and organ donation (see Chap. 16).
Professionals need to work as a team to meet diverse patient needs, to facilitate certain decisions, to develop
comprehensive plans of care, and to help patients modify their daily activities to meet test requirements in all three
phases. It is a given that institutional protocols are followed.

PRETEST PHASE: ELEMENTS OF SAFE, EFFECTIVE, INFORMED CARE
The emphasis of pretest care is on appropriate test selection, obtaining proper consent, proper patient preparation,
individualized patient education, emotional support, and effective communication. These interventions are key to
achieving the desired outcomes and preventing misunderstandings and errors.
Basic Knowledge and Necessary Skills
Know the test terminology, purpose, process, procedure, and normal test reference values or results. The names of
diseases are a convenient way of briefly stating the endpoint of a diagnostic process that begins with assessment of
symptoms and signs and ends with knowledge of causation and detection of underlying disorders of structure and
function.
The clinical value of a test is related to its sensitivity, its specificity, and the incidence of the disease in the population
tested. Sensitivity and specificity do not change with different populations of ill and healthy patients. The predictive value
of the same test can vary significantly with age, gender, and geographic location.
Specificity refers to the ability of a test to identify correctly those individuals who do not have the disease. The division
formula for specificity is as follows:

Sensitivity refers to the ability of a test to correctly identify those individuals who truly have the disease. The division
formula for sensitivity is as follows:

Incidence refers to the prevalence of a disease in a population or community. The predictive value of the same test can
be very different when applied to people of differing ages, genders, geographic locations, and cultures.
Predicted Values refer to the ability of a screening test result to correctly identify the disease state. True-positive results
correctly identify individuals who actually have the disease, and true-negative results correctly identify individuals who do
not actually have the disease. Positive predictive value equals the percentage of positive tests with true-positive results
(ie, the individual does have the disease). Negative predictive value refers to the percentage of negative tests with
true-negative results (ie, the individual does not have the disease).
See Table 1.4 for an example that demonstrates the specificity, sensitivity, and predictive values for a new screening test
to identify the cystic fibrosis gene.

Table 1.4 Sample Test Results
Test Result Have Gene for Cystic Fibrosis Do Not Have Gene for Cystic Fibrosis Total
Positive
Negative
TOTAL

62
15
77

5
341
346

67
356
423

Thus, this new screening test will give a false-negative result about 20% of the time (eg, the person does have the cystic
fibrosis gene but his or her test results are negative).

Thus, there is about an 8% change that the person will test positive for the cystic fibrosis gene but does not have it.

Thus, there is about a 5% chance that the person will test negative for the cystic fibrosis gene but actually does have it.
Look at both current and previous test results and review the most recent laboratory data first, then work sequentially
backward to evaluate trends or changes from previous data. The patient's plan of care may need to be modified because
of test results and changes in medical management.
Testing Environments
Diagnostic testing occurs in many different environments. Many test sites have shifted into community settings and away
from hospitals and clinics.
Point-of-Care Testing refers to tests done in the primary care setting. In acute care settings (eg, critical care units,
ambulances), state-of-the-art testing can produce rapid reporting of test results.
Testing in the home care environment requires skill in procedures such as drawing blood samples, collecting samples
from retention catheters, proper specimen labeling, documentation, specimen handling, and specimen transporting.
Moreover, teaching the patient and his or her significant others how to collect specimens is an important part of the
process.
In occupational health environments, testing may be done to reduce or prevent known workplace hazards (eg, exposure
to lead) and to monitor identified health problems. This can include preemployment baseline screening, periodic
monitoring of exposure to potentially hazardous workplace substances, and drug screening. Skill in drawing blood
samples, performing breathing tests, monitoring chain of custody (see page 226 in Chap. 3), and obtaining properly
signed and witnessed consent forms for drug testing is required.
More pretest, posttest, and follow-up testing occurs in nursing homes because patients are more frequently taken or
transferred to hospitals for more complex procedures (eg, computed tomography [CT] scans, endoscopies), whereas this
is not the case with routine testing. Increasing numbers of “full code” (ie, resuscitation) orders leads to greater numbers
and varieties of tests. Additionally, confused, combative, or uncooperative behaviors are seen more frequently in these
settings. An attitude adopted by nursing home patients of “not wanting to be bothered” or engaging in outright refusal to
undergo prescribed tests can make testing difficult. Consequently, understanding patient behaviors and using
appropriate communication strategies and interventions for this population are necessary skills for practicing in this
arena.
For those who practice in the realm of public health, diagnostic test responsibilities focus on wellness screenings,
preventive services, disease control, counseling, and treatment of individuals with problems. Case finding frequently
occurs at health fairs, outreach centers, homeless shelters, neighborhood nurse offices, mobile health vans, and church
settings. Responsibilities vary according to setting and may include providing test information, procuring specimens, and
providing referrals to appropriate caregivers. These responsibilities may even extend to transporting and preparing
specimens for analysis or actually performing specimen analysis (eg, stool tests for occult blood, TB skin testing, and
procuring blood or saliva samples for HIV/acquired immunodeficiency syndrome [AIDS] testing).
History and Assessment
Obtain a relevant, current health history; perform a physical assessment if indicated. Identify conditions that could
influence the actual testing process or test outcomes (eg, pregnancy, diabetes, cultural diversity, language barrier,
physical impairment, altered mental state).
1. Perform a risk assessment for potential injury or noncompliance.
2. Identify contraindications to testing such as allergies (eg, iodine, latex, medications, contrast media). Records of
previous diagnostic procedures may provide clues.
3. Assess for coping styles and knowledge or teaching needs.

4. Assess fears and phobias (eg, claustrophobia, “panic attacks,” fear of needles and blood). Ascertain what
strategies the patient uses to deal with these reactions and try to accommodate these.
5. Observe standard/universal precautions with every patient (see Appendix A). A patient may choose not to disclose
drug or alcohol use or HIV and hepatitis risks.
6. Document relevant data. Address patient concerns and questions. This information adds to the database for
collaborative problem-solving activities among the medical, laboratory/ diagnostic, and nursing disciplines.
Reimbursement for Diagnostic Services
Differences in both diagnostic care services and reimbursement may vary between private and government insurance.
Nonetheless, quality of care should not be compromised in favor of cost reduction. Advocate for patients regarding
insurance coverage for diagnostic services. Inform the patient and his or her family or significant others that it may be
necessary to check with their insurance company before laboratory and diagnostic testing to make certain that costs are
covered.
Many insurance companies employ case managers as gatekeepers for monitoring costs, diagnostic tests ordered, and
other care. As a result, the insurance company or third-party payer may reimburse only for certain tests or procedures or
may not cover tests considered by them to be preventive care. So that reimbursement completely covers diagnostic
services provided, be sure to include proper documentation and proper Common Practice Terminology (CPT) codes.
Note date laboratory service is performed and date specimen is collected (must use). Based on 1999 data, Chart 1.3 lists
laboratory tests that are covered by most insurance carriers, both private and government.

Chart 1.3 Tests Covered by Most Insurance Carriers

Alpha-fetoprotein

Human chorionic gonadotropin

Blood counts

Lipids

Blood glucose testing

Partial thromboplastin time

Carcinoembryonic antigen

Prostate-specific antigen

Collagen crosslinks, any method (urine osteoporosis) Prothrombin time
Digoxin therapeutic drug assay

Serum iron studies

Fecal occult blood

Thyroid testing

Gamma-glutamyltransferase

Tumor antigen by immunoassay—CA125

Glycated hemoglobin/glycated protein

Tumor antigen by immunoassay—CA15-3/CA27

Hepatitis panel

Tumor antigen by immunoassay—CA19-9

HIV testing (diagnosis)

Urine culture

HIV testing (prognosis including monitoring)

Methodology of Testing
Follow testing procedures accurately. Verify orders and document them with complete, accurate, and legible information.
Document all drugs the patient is taking because these may influence test outcomes (see Appendix J).
1. Ensure that specimens are correctly obtained, preserved, handled, labeled, and delivered to the appropriate
department. For example, it is not generally acceptable to draw blood samples when an intravenous line is infusing
proximal to the intended puncture site.
2. Observe precautions for patients in isolation. Use standard/universal precautions.
3. As much as possible, coordinate patient activities with testing schedules to avoid conflicts with meal times and
administration of medications, treatments, or other diagnostic tests and travel time.
a. Maintain NPO (ie, nothing by mouth) status when necessary.
b. Administer the proper medications in a timely manner. Schedule tests requiring contrast substances in the
proper sequence so as not to invalidate succeeding tests.
Interfering Factors
Minimize test outcome deviations by following proper test protocols. Make certain the patient and his or her significant
others know what is expected of them. Written instructions are very helpful.

Reasons for deviations may include the following:
1.
2.
3.
4.
5.
6.
7.

Incorrect specimen collection, handling, storage, or labeling
Wrong preservative or lack of preservative
Delayed specimen delivery
Incorrect or incomplete patient preparation
Hemolyzed blood samples
Incomplete sample collection, especially of timed samples
Old or deteriorating specimens

Patient factors that can alter test results may include the following:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.

Incorrect pretest diet
Current drug therapy
Type of illness
Dehydration
Position or activity at time of specimen collection
Postprandial status (ie, time patient last ate)
Time of day
Pregnancy
Level of patient knowledge and understanding of testing process
Stress
Nonadherence or noncompliance with instructions and pretest preparation
Undisclosed drug or alcohol use
Age and gender

Avoiding Errors
To avoid costly mistakes, know what equipment and supplies are needed and how the test is performed. Communication
errors account for more incorrect results than do technical errors. Properly identify and label every specimen as soon as
it is obtained. Determine the type of sample needed and the collection method to be used. Is the test invasive or
noninvasive? Are contrast media injected or swallowed? Is there a need to fast? Are fluids restricted or forced? Are
medications administered or withheld? What is the approximate length of the procedure? Are consent forms and
conscious sedation, oxygen, analgesia, or anesthesia required? Report test results as soon as possible. “Critical” or
“panic” values must be reported to the proper persons immediately (STAT).
Instruct patients and their significant others regarding their responsibilities. Accurately outline the steps of the testing
process and any restrictions that may apply. Conscientious, clear, timely communication among health care departments
can reduce errors and inconvenience to both staff and patients.
Proper Preparation
Prepare the patient correctly. This preparation begins at the time of scheduling.
1. Provide information about testing site and give directions for locating the facility; allow time to enter the facility and
find the specific testing laboratory. If a copy of the written test order was given to the patient to bring to the
laboratory, interpret the test order. For example, an order for a renal sonogram means that an ultrasound of the
kidney will be done to “rule out” (RO) evidence or presence of abnormality or suspected problem. The terms
“ultrasound” and “sonogram” are used interchangeably.
2. Plan to be at the department 15 minutes before testing if the test is scheduled for a specific time. Review all pretest
instructions and be certain they are explained clearly (eg, “fasting” directions for test, tell patient what fasting
actually means).
3. Be aware of special needs of those with conditions such as physical limitations or disabilities, ostomies, or
diabetes; children; elderly patients; and culturally diverse patients.
4. Give simple, accurate, precise instructions according to the patient's level of understanding. For example, the
patient needs to know when and what to eat and drink or how long to fast.
5. Encourage dialogue about fears and apprehensions. “Walking” a patient through the procedure using imagery and
relaxation techniques may help them to cope with anxieties. Never underestimate the value of a caring presence.
6. Assess for the patient's ability to read and understand instructions. Poor eyesight or hearing difficulties may impair
understanding and compliance. Speak slowly and clearly. Do not bombard the patient with information. Instruct the
patient to use assistive devices such as eyeglasses and hearing aids if necessary. Clear, written instructions can
reinforce verbal instructions and should be used whenever possible. In some cases, a translator or “signer,” or legal
representative may be necessary.
7. Assess for language and cultural barriers. Patients behave according to personal values, perceptions, beliefs,
traditions, and cultural and ethnic influences. Take these into consideration and value the patient's uniqueness to
the highest degree possible.
8. Document accurately in all testing phases.
Patient Education
Educate the patient and family regarding the testing process and what will be expected of them. Record the date, time,
type of teaching, information given, and to whom the information was given.
1. Giving sensory and objective information that relates to what the patient will likely physically feel and the equipment

that will be used is important so that patients can “see” a realistic representation of what will occur. Avoid technical
and medical jargon and adapt information to the patient's level of understanding. Slang terms may be necessary to
get a point across.
2. Encourage questions and verbalization of feelings, fears, and concerns. Do not dismiss, minimize, or invalidate the
patient's anxiety through trivial remarks such as “Don't worry.” Develop “listening ears and eyes” skills. Be aware of
nonverbal signals (ie, body language) because these frequently provide a more accurate picture of what the patient
really feels than what he or she says. Above all, be nonjudgmental.
3. Emphasize that there is usually a waiting period (ie, “turn-around time”) before test results are relayed back to the
clinicians and nursing unit. The patient may have to wait several days for results. Offer listening, presence, and
support during this time of great concern and anxiety.
4. Record test result information. Include the patient's response. Just because something is taught does not
necessarily mean that it is learned or accepted. The possibility that a diagnosis will require a patient to make
significant lifestyle changes (eg, diabetes) requires intense support, understanding, education, and motivation.
Document specific names of audiovisual and reading materials to be used for audit, reimbursement, and
accreditation purposes.
Testing Protocols
Develop consistent protocols for teaching and testing that encompass comprehensive pretest, intratest, and posttest care
modalities.
Prepare patients for those aspects of the procedure experienced by the majority of patients. Clinicians can collaborate to
collect data and to develop a list of common patient experiences, responses, and reactions.
Patient Independence
Allow the patient to maintain as much control as possible during the diagnostic phases to reduce stress and anxiety.
Include the patient and his or her significant others in decision making. Because of factors such as anxiety, language
barriers, and physical or emotional impairments, the patient may not fully understand and assimilate instructions and
explanations. To validate the patient's understanding of what is presented, ask the patient to repeat instructions given to
evaluate assimilation and understanding of presented information.
Include and reinforce information about the diagnostic plan, the procedure, time frames, and the patient's role in the
testing process.
Test Results
Know normal or reference values.
1. Normal ranges can vary to some degree from laboratory to laboratory. Frequently, this is because of the particular
type of equipment used. Theoretically, “normal” can refer to the ideal health state, to average reference values, or
to types of statistical distribution. Normal values are those that fall within 2 standard deviations (ie, random
variation) of the mean value for the normal population.
2. The reported reference range for a test can vary according to the laboratory used, the method employed, the
population tested, and methods of specimen collection and preservation.
3. The majority of normal blood test values are determined by measuring “fasting” specimens.
4. Be aware of specific influences on test results. For example, patient posture is important when plasma volume is
measured because this value is 12% to 15% greater in a person who has been supine for several hours. Changing
from a supine to a standing position can alter values as follows: increased hemoglobin (Hb), red blood cell (RBC)
count, hematocrit (Hct), calcium (Ca), potassium (K), phosphorus (P), aspartate aminotransferase (AST),
phosphatases, total protein, albumin, cholesterol, and triglycerides. Going from an upright to a supine position
results in increased hematocrit, calcium, total protein, and cholesterol. A tourniquet applied for > 1 minute produces
laboratory value increases in protein (5%), iron (6.7%), AST (9.3%), and cholesterol (5%) and decreases in K +
(6%) and creatinine (2%–3%).
Laboratories must specify their own normal ranges. Many factors affect laboratory test values and influence ranges.
Thus, values may be normal under one set of prevailing conditions but may exhibit different limits in other circumstances.
Age, gender, race, environment, posture, diurnal and other cyclic variations, foods, beverages, fasting or postprandial
state, drugs, and exercise can affect derived values. Interpretation of laboratory results must always be in the context of
the patient's state of being. Circumstances such as hydration, nutrition, fasting state, mental status, or compliance with
test protocols are only a few of the situations that can influence test outcomes.
Laboratory Reports
Scientific publications and many professional organizations are changing clinical laboratory data values from
conventional units to Systéme International (SI) units. Currently, many data are reported in both ways.
The SI system uses seven dimensionally independent units of measurement to provide logical and consistent
measurements. For example, SI concentrations are written as amount per volume (moles or millimoles per liter) rather
than as mass per volume (grams, milligrams, or milliequivalents per deciliter, 100 milliliters, or liter). Numerical values
may differ between systems or may be the same. For example, chloride is the same in both systems: 95 to 105 mEq/L
(conventional) and 95 to 105 mmol/L (SI) (see Appendix D).

Margins of Error
Recognize margins of error. For example, if a patient has a battery of chemistry tests, the possibility exists that some
tests will be abnormal owing purely to chance. This occurs because a significant margin of error arises from the arbitrary
setting of limits. Moreover, if a laboratory test is considered normal up to the 95th percentile, then 5 times out of 100, the
test will show an abnormality even though a patient is not ill. A second test performed on the same sample will probably
yield the following: 0.95 × 0.95, or 90.25%. This means that 9.75 times out of 100, a test will show an abnormality even
though the person has no underlying health disorder. Each successive testing will produce a higher percentage of
abnormal results. If the patient has a group of tests performed on one blood sample, the possibility that some of the tests
will “read abnormal” due purely to chance is not uncommon.
Ethics and the Law
Consider legal and ethical implications. These include the patient's right to information, properly signed and witnessed
consent forms, and explanations and instructions regarding chain-of-custody requirements and risks as well as benefits
of tests.
1. Chain of custody is a legal term descriptive of a procedure to ensure specimen integrity from collection to transport
to receipt to analysis and specimen storage. A special form is used to provide a written record. The right to
informed consent before certain tests and procedures pertains to patient autonomy, the ethical right of
self-determination, the legal right to be free of procedures to which one does not consent, and to determine what
will be done to one's own person. Risks, benefits, and alternatives are explained and written consent obtained well
in advance of the procedure.
2. The patient must demonstrate appropriate cognitive and reasoning faculties to sign a legally valid consent.
Conversely, a patient may not legally give consent while under the immediate influence of sedation, anesthetic
agents, or certain classes of analgesics and tranquilizers. If the patient cannot validly and legally sign a consent
form, an appropriately qualified individual may give consent for the patient.
3. Guidelines and wishes set forth in advance directives or “living will”–type documents must be honored, especially in
life-threatening situations. Such directives may prevent more sophisticated invasive procedures from being
performed. Some states have legislated that patients can procure do-not-resuscitate (DNR) orders and medical
DNR bracelets that indicate their wishes. A copy of a patient's advance directives in the health care record can be
very helpful in unpredictable situations.
4. A collaborative team approach is essential for responsible, lawful, and ethical patient-focused care. The clinician
who orders the test has a responsibility to inform the patient about risks and test results and to discuss alternatives
for follow-up care. Other caregivers can provide additional information and clarification and can support the patient
and family in achieving the best possible outcomes. The duty to maintain confidentiality, to provide freedom of
choice, and to report infectious diseases may result in ethical dilemmas.
Respect for the dignity of the individual reflects basic ethical considerations. Patients and family have a right to consent,
to question, to request other opinions, and to refuse diagnostic tests. Conversely, caregivers have the right to know the
diagnoses of the patients they care for so that they can minimize the risks to themselves.
Patient's Bill of Rights and Patient Responsibilities
Patients have a right to expect that an agency's or institution's policies and procedures will ensure certain rights and
responsibilities for them. At all times, the patient has the right:
1. To considerate, honest, respectful care, with consideration given to privacy and maintenance of personal dignity,
cultural and personal values and beliefs, and physical and developmental needs, regardless of the setting.
2. To be involved in decision making and to participate actively, if so desired, in the testing process, assuming the
patient is competent to make these choices.
3. To participate in the informed consent process before testing and to be told of the benefits, risks, and reasonable
alternative approaches to tests ordered.
4. To be informed regarding test costs and reimbursement responsibility.
5. To refuse diagnostic testing.
6. To expect to have the support of family or significant others, if so desired and appropriate during the testing
process.
7. To expect that standards of care will be followed by all personnel involved in the testing process.
8. To expect safe, skilled, quality care provided by trained personnel with expertise in their field.
9. To expect patient and family education and instructions regarding all phases of the testing process and procedure,
including the nature and purpose of the test, pretest preparation, actual testing, posttest care benefits, risks, side
effects, and complications. Information should be provided in a sensitive and objective manner.
10. To expect to be informed in a timely manner of test results and implications, treatment, and future testing if
necessary.
11. To expect to be counseled appropriately regarding abnormal test outcomes as well as alternative options and
available treatments.
12. To expect to have acceptable pain control and comfort measures provided throughout the testing process.
13. To expect that all verbal, written, and electronic communication, medical records, and medical record transfers will
be accurate and confidential. Exception: when reporting of situation is required by law (eg, certain infectious
diseases, child abuse).
The patient has the following responsibilities:
1. To comply with test requirements (eg, fasting, special preparations, medications, enemas) and to inform the

2.
3.
4.
5.
6.
7.
8.

clinician if they are unable to do so.
To report active or chronic disease conditions that may alter test outcomes, be adversely affected by the testing
process, or pose a risk to health care providers (eg, HIV, hepatitis).
To keep appointments for diagnostic procedures and follow-up testing.
To disclose drug and alcohol use as well as use of supplements and herbal products despite being informed that
these products could affect test outcomes (eg, erroneous test results).
To disclose allergies and past history of complications or adverse reactions to tests. Example: Reaction to contrast
materials.
To report any adverse effects attributed to tests and procedures after being advised regarding signs and symptoms
of such.
To supply specimens that are their own.
To report visual or hearing impairments or inability to read, write, or understand English.

Cultural Sensitivity
Preserving the cultural well-being of any individual or group promotes compliance with testing and easier recovery from
routine as well as more invasive and complex procedures. Sensitive questioning and observation may provide
information about certain cultural traditions, concerns, and practices related to health. For example, the Hmong people
believe the soul resides in the head and that no one should touch an adult's head without permission. Patting a Hmong
child on the head may violate this belief. Health care personnel should make an effort to understand the cultural
differences of populations they serve without passing judgment. Most people of other cultures are willing to share this
information if they feel it will be respected. Sometimes, a translator is necessary for accurate communication.
Many cultures have diverse beliefs about diagnostic testing that requires blood sampling. For example, alarm about
having blood specimens drawn or concerns regarding the disposal of body fluids or tissue may require health care
workers to demonstrate the utmost patience, sensitivity, and tact when communicating information about blood tests.

INTRATEST PHASE: ELEMENTS OF SAFE, EFFECTIVE, INFORMED CARE
Basic Knowledge and Required Skills
Intratest care focuses on specimen or tissue collection, monitoring the testing environment tissue collection, performing
and/or assisting with procedures, providing emotional and physical comfort and reassurance, administering analgesics
and sedatives, and monitoring vital signs and other parameters during testing. The clinician must have basic knowledge
about the procedure and test and should have the required skills to perform testing or to assist in the process. Safe
practices, proper collection of specimens, minimizing delays, providing support to the patient, preparing or administering
analgesia and sedatives, monitoring various parameters as necessary, and being alert to potential side effects or
complications are integral activities of the intratest phase. Invasive procedures place patients at greater risk for
complications and require ongoing vigilance and observation. Monitoring fluid intake and loss, body temperature, and
respiratory and cardiovascular systems and treating problems in these domains require critical thinking and quick
responses.
Infection Control
Institute accepted infection control protocols. Observe special measures and sterile techniques as appropriate. Identify
patients at risk for infection. Institute strict respiratory and contact isolation as necessary. Quality assurance requires
proper collection, transport, and receipt of specimens and use of properly cleaned and prepared instruments and
equipment. Appendix A offers more information on standard precautions for safe practice and infection control and
isolation. The term standard precautions refers to a system of disease control that presupposes each direct contact with
body fluids or tissues is potentially infectious and that every person exposed to these must protect himself or herself.
Consequently, health care workers must be both informed and conscientious about adhering to standard precautions and
strict infection control guidelines. It goes without saying that health care workers must be scrupulous about proper hand
hygiene (see Appendix A). Proper protective clothing and other devices must be worn as necessary.
Procurement and disposal of specimens according to U.S. Occupational Safety and Health Administration (OSHA)
standards must be adhered to. Moreover, institutions may have procedures and policies of their own to ensure
compliance (eg, specimens are to be placed directly into biohazard bags).

NOTE
Standard precautions (formerly known as universal precautions) prevail in all situations in which risk for exposure to
blood, tissue, and other body fluids is even remotely possible. The terms standard precautions and universal
precautions are often used interchangeably.
Collaborative Approaches
A collaborative team approach is necessary for most procedures. Clinicians must assist and understand each other's role
in the procedure. Invasive procedures (such as lumbar punctures or cystoscopy) place patients at greater risk for
complications and usually require closer monitoring during the test. Frequently, administration of intravenous (IV)
sedation and other drugs is part of the procedure. Astute ongoing observation of the patient and critical thinking and
quick decision-making skills during intense situations is a requisite for clinicians in these settings.

Risk Management
Assess for and provide a safe environment for the patient at all times. Identify patients at risk and environments that may
pose a risk. Previous falls, cerebrovascular accident (CVA), neuromuscular disorders, loss of balance, or use of
ambulatory and other assistive devices are contributory risk factors. Prevention of complications and management of risk
factors are an important part of the intratest phase. As part of risk management, observe standard precautions and
infection control protocols as necessary (see Appendix A, Appendix B, and Appendix C).
Use special care during procedures that include iodine and barium contrasts, radiopharmaceuticals, latex products,
conscious sedation, and analgesia (see Chap. 9, Chap. 10, and Chap. 15 for precautions for imaging procedures.)
Certain risk factors contribute to a higher incidence of adverse reactions when contrast agents and radiopharmaceuticals
are used ( Table 1.5).

Table 1.5 Classification of Risk Factors
Preexisting Disorders Contributing Elements
Asthma
Diabetes
Liver insufficiency
Multiple myeloma
Pheochromocytoma
Renal failure
Seizure history

Allergy
Age-related (newborn and older adults)
Dehydration
Frequent use of contrast agents
High dosage of contrast and radiopharmaceuticals
Previous reaction to contrast agents

Remove jewelry, false teeth, and other prosthetic devices as necessary. Check for NPO or fasting status if appropriate.
Specimens and Procedures
Assist with and/or conduct certain diagnostic procedures. Examples of the types of assisted procedures include
endoscopy, lumbar puncture, and cardiac catheterization. Diagnostic procedures often performed independently of other
medical personnel include Papanicolaou (Pap) smears, centrifugation of blood samples, ECGs, breathing tests, and
pulse oximetry. For example, the pulse oximeter is used to monitor noninvasively the oxygen saturation (SpO 2); S

O 2 refers to pulse oximetry, whereas S

O 2 refers to arterial saturation measured on an arterial blood sample. Sensors may be applied on the index, middle, or
ring finger; on the nose, earlobe, toe, or foot; and on the forehead. Be aware of factors that interfere with accurate
results, such as patient movement, ambient light, electronic interference, artificial nails and polish, anemia, edema, or
poor circulation to an area. Chapter 14 provides more information on pulse oximetry.
Collecting specimens and conducting procedures are the main interventions in the diagnostic pretest and intratest
phases. Procure, process, transport, and store specimens properly. The community environment and health care setting
in which testing takes place dictate protocols for doing this. Everyone involved in the process must have a thorough
understanding of testing principles and protocols and must adhere to them to ensure accurate results.
Determine specimen type needed and method of sample procurement. Special equipment and supplies may be
necessary (eg, sterile containers, special kits).
Collection by the patient requires patient cooperation, understanding, and instruction. It does not always require direct
supervision. Conversely, supervised collection requires supervision of the patient by trained personnel during specimen
collection. Examples of these two types of collection include a routine urine sample collected by the patient privately
versus a urine sample procured in a supervised setting for drug screening.
A third method of collection requires that the clinician perform the entire collection. An example of this type of collection is
aspirating a urine sample from an indwelling catheter.
Time of collection is also important. For example, results from a fasting blood glucose test versus results from a
2-hour-postprandial blood glucose test are significantly different as diagnostic parameters.
Specimens can be rejected for analysis because of factors related to the specimen itself or to the collection process (
Table 1.6).

Table 1.6 Errors in Collection
Specimen Errors

Collector Errors

Insufficient volume
Improper type
Insufficient number of samples
Wrong transport medium or wrong or absent
preservative
Air bubbles in tube
Storage at incorrect temperature

Transport delay
Improper collection method
Wrong specimen container
Wrong time

Incorrect storage
Unlabeled or mislabeled specimen and/or wrong patient identification
information
Incorrect order of draw
Improperly completed forms or computer data entry
Do not cut test tapes in half
Discrepancies between test ordered and specimen collected
Improper centrifugation time
Failure to properly transcribe and process orders
Note: Observing institutional protocols can prevent mishaps.

Blood collection is normally done by trained persons. (An exception is the self-test for blood glucose using equipment
designed specifically for that purpose.) The time of collection is an important factor (eg, a sequence of samples for a
cardiac panel). For example, a “peak” drug-level blood specimen is collected when highest drug concentration in the
blood is expected. This type of test is used for therapeutic drug monitoring and dosing. Conversely, a “trough” sample is
collected when lowest drug concentration is expected. These types of tests are used for therapeutic drug monitoring, and
specimens are collected and results reported before the next scheduled dose of medication.
Legal and forensic specimens are collected as evidence (see Appendix L) in legal proceedings, criminal investigations,
and after death. Examples include DNA samples and drug and alcohol levels. Factors such as chain-of-custody
situations and witnessed collections may be involved.
The following list addresses some general comments about specimen collections:
1.
2.
3.
4.
5.

Stool and urine collection requires clean, dry containers and kits.
Timed urine collection requires refrigeration and/or containers with special additives.
Sterile, dry containers and special kits are needed for midstream clean-catch urine specimens.
Oral, saliva, and sputum specimens require specific techniques and kits and, sometimes, special preservatives.
Blood collection equipment includes gloves, needles, collection tubes, syringes, tourniquets, needle disposal
containers, lancets for skin puncture, cleansing agents or antimicrobial skin preparations, and adhesive bandages.
6. Color-coded stoppers and tubes indicate the type of additive present in the collection tube ( Table 1.7).
Table 1.7 Blood Specimen Collections
Collection Tube Color and
Additives *

Use and Precautions

Yellow-topped tube: sodium
polyethylene sulfonate (SPS)
Red or gold serum separator tubes
(SST); no anticoagulant

For collection of blood cultures; aseptic technique for blood draw; invert tube
7–10 times to prevent clot formation
For collecting serum samples such as chemistry analysis. SST tubes should
be gently inverted (completely, end over end) 5 times after collection to
ensure mixing of clot activator with blood and clotting within 30 minutes.
After the 30-minute period, centrifuge promptly at designated relative
centrifugal force (rcf) for 15 ± 5 minutes to separate serum from cells. Serum
can be stored in gel separator tubes after centrifugation for up to 48 hours.
Do not freeze SST tubes. If frozen specimen is needed, separate serum into
a labeled plastic transfer vial. Serum separation tubes must not be used to
obtain therapeutic drug levels because the gel may lower the values.
For serum chemistry, serology, blood bank, collection of clotted blood
specimens
For aluminum, arsenic, chromium, copper, nickel, and zinc levels; tube free
of trace elements

Red-topped (plain) tube: no
anticoagulant, no additive
Royal blue–topped tube: without
ethylenediaminetetraacetic acid
(EDTA) or sodium heparin (no
anticoagulant—blood will clot)
Light blue–topped tube: with
sodium citrate as anticoagulant
(removes calcium to prevent
clotting)
Gold or red marbled–topped tube:
serum gel separator tube (SST)

For plasma-coagulation studies (eg, prothrombin times [PT]; PT/partial
thromboplastin time [PTT] and factor assays). The tube must be allowed to
fill to its capacity or an improper blood/anticoagulant ratio will invalidate
coagulation test results. Invert tube 7–10 times to prevent clotting.
For serum, used for most chemistry tests; these tubes should be gently
inverted 5 times after collection to ensure mixing of clot activator with blood
and clotting within 30 minutes. After 3-minute period, centrifuge promptly at
designated rcf for 15 ± 5 minutes to separate serum from cells. Serum can
be stored in gel separator tubes after centrifugation for up to 48 hours. Do
not freeze SST tubes. If frozen specimen is needed, separate serum into a
labeled plastic transfer vial. Serum separation tubes must not be used for
therapeutic drug levels. The gel may lower values. Not for blood bank use

Light green marbled–topped tube:
gel separator/lithium, heparin as
anticoagulant
Tan/brown-topped tube: with
heparin as anticoagulant
Lavender-topped tube: with EDTA;
removes calcium to prevent clotting

For potassium determination

For heparinized plasma specimens for testing lead levels (ie, lead-free
tube). Invert tube 7–10 times.
For whole blood and plasma, for hematology and complete blood counts
(CBCs); prevents the filled tube from clotting. If the tube is less than
half-filled, the proportion of anticoagulant to blood may be sufficiently altered
to produce unreliable laboratory test results. Invert tube 6–8 times.
For toxicology, cadmium and mercury: tube free of trace elements. Invert
tube 7–10 times.

Royal blue–topped tube: no
additive with EDTA or sodium
heparin anticoagulant
Gray-topped tube: with potassium
For glucose levels, glucose tolerance levels, and alcohol levels.
oxalate and sodium fluoride
Plain pink tube: no additive or
For blood bank
anticoagulant
Black tube: with sodium citrate
For Westergren sedimentation rate
(binds calcium)
Green-topped tube: with
For heparinized plasma specimens, plasma chemistries, arterial blood
anticoagulant heparin (sodium,
gases, and special tests such as ammonia levels, hormones, and
lithium, and ammonium heparin)
electrolytes. Invert 7–10 times to prevent clot formation.
*List is arranged in sequence of draw according to NCCLS guidelines.

7. Additives preserve the specimen, prevent deterioration and coagulation, and/or block action of certain enzymes in
blood cells.
8. Tubes with anticoagulants should be gently and completely inverted (end over end) 7 to 10 times after collection.
This process ensures complete mixing of anticoagulants with the blood sample and prevents clot formation.
9. Store specimens properly after collecting or transport them to the laboratory immediately for processing and
analysis if possible. Failure to do so may result in specimen deterioration. STAT-ordered tests should always be
hand-delivered to the laboratory and then processed as STAT.
10. Unacceptable specimens lead to increased costs and time wasted in getting results to the clinician, patient,
institution, and third-party payer. Exposure to sunlight, air, or other substances and warming or cooling are
examples of things that can alter specimen integrity (see Appendix E). Check with the laboratory for proper storage
(eg, ice, ice water, separate from ice), transport, and time limits.
11. As environments for specimen collection become more variable, modified procedures and protocols require the
clinician to keep abreast of the latest information related to these factors (see Appendix E).
Equipment and Supplies
1. Use required kits, equipment, and supplies. Special kits are used for obtaining heel sticks and finger sticks, blood
alcohol samples, saliva or oral fluid specimens, and urine specimens.
2. Do not use if you notice a defect (eg, moisture, pinholes, tears). In cases of sexual assault, special rape kits are
required and a strict procedure, consisting of several steps, is followed.
3. Operating special equipment such as video monitors for endoscopic procedures may be required in some
instances. Familiarity with current audiovisual technology is necessary.
4. Taking photographs of injuries in suspected abuse situations is another example.
5. Use barrier drapes as directed. For example, arthroscopy drapes are positioned with the fluid control pouch at the
knee.
6. Maintain aseptic technique during certain procedures (eg, cystoscopy, bone marrow biopsy).
Family Presence
Involving family members in the diagnostic care process has helped families by making them active participants.
Facilitating family presence may provide the opportunity to calm the patient, offer additional comfort, and reduce anxiety
and fear. However, some families may find the option of observing procedures to be distressing or uncomfortable. Other
patients may not want family members present. Nurses acting as patient advocates recognize the importance of
supporting the patient's need for reassurance and the family's need and right to be present during diagnostic procedures.
The goal is to achieve an acceptable balance between all parties.
Positioning for Procedures
Proper body positioning and alignment involves placing the patient in the best possible position for the procedure and
aligning the body correctly for optimal respiratory and circulatory function. Positions include jackknife, prone, lithotomy,
sitting, supine, and Trendelenburg. Using positioning devices, arranging padding, and repositioning are important
interventions to prevent skin pressure and skin breakdown. The potential adverse effects of various positions, especially
during lengthy procedures, include skin breakdown, venous compression, sciatic nerve injury, muscle injury, and low
back strain. Necessary positioning skills include ensuring that the patient's airway, IV lines, skin integrity, and monitoring
devices are not compromised and identifying those persons at potential risk for injury (eg, elderly, thin, frail, unconscious
patients) before positioning. If wounds, skin breakdown, abrasions, or bruises are present before the procedure,
accurately document their presence and location.
Administration of Drugs and Solutions

All drugs and solutions administered during diagnostic procedures are given according to accepted protocols. Drugs are
given by mouth, by intubation, parenterally (intramuscularly, intravenously, or subcutaneously), and by local or topical
skin applications. IV fluids and endoscopic irrigating fluids are commonly administered.
Be aware of the potential for adverse reactions to drugs. Before procedure begins, confirm previous drug problems with
the patient before the procedure. Risks for injury are related to hypersensitivity, allergic or toxic reactions, impaired drug
tolerance due to liver or kidney malfunction, extravasation of intravenous fluids, and absorption of irrigating fluids into the
systemic circulation. Required skills include managing airways and breathing patterns; monitoring fluid intake and loss;
monitoring body, skin, and core temperature; and observing the effects of sedation and analgesia ( Appendix C) (eg, vital
signs, rashes, edema). Use tape with caution, especially when skin integrity can be easily compromised, as in frail elderly
patients.
Management of Environment
The main goal of environmental control is safe practice to ensure that the patient is free from injury related to
environmental hazards and is free from discomfort. Be attentive to temperature and air quality; the patient's temperature;
exposure to noise, radiation, latex, and noxious odors; sanitation; and cleanliness.
1. Eliminate or modify sensory stimuli (eg, noise, odors, sounds).
2. Post a PATIENT AWAKE sign if the patient is awake during a procedure or PATIENT ASLEEP for sleep studies.
3. Be sensitive to conversation among team members in the presence of the patient. At best, it can be annoying to the
patient; at worst, it may be misinterpreted and have far-reaching negative effects and consequences.
Pain Control, Comfort Measures, and Patient Monitoring
Provide proper information, reassurance, and support throughout the entire procedure to allay anxiety and fear.
Administer sedatives, pain medication, or antiemetics as ordered. Uphold the dignity of each patient, provide privacy, and
minimize any situation that might cause embarrassment or stress. Continue monitoring throughout procedures as well as
after completion, if indicated.
1. Do not permit the patient to remain disrobed any longer than necessary. Allow personal clothing and other
accessories such as rings or religious medals provided they do not pose a risk or interfere with the procedure.
Ensure a reasonable degree of privacy.
1. Control pain and provide comfort measures. IV conscious sedation and drugs given to reverse the effects of test
medications are part of this scenario. Allow the patient to maintain as much control as possible during all testing
phases without compromising safety, the process and procedure, and test integrity. If possible, plan ahead to
accommodate persons with special needs such as learning disabilities, visual or hearing impairment, ostomy, or
diabetes management.
2. Monitor and document vital signs and other relevant parameters (eg, pulse oximetry, ECG) throughout the
procedure. Observe for problems and abnormal reactions and take appropriate measures to correct such situations.
Make sure emergency equipment is readily available and functional.
3. Document the patient's response to the procedure during all phases. Also document significant events or situations
that occur during testing. Record disposition of specimens.

POSTTEST PHASE: ELEMENTS OF SAFE, EFFECTIVE, INFORMED CARE
Basic Knowledge and Necessary Skills
The focus of the posttest phase is on patient aftercare and the follow-up activities, observations, and monitoring
necessary to prevent or minimize complications. Evaluation of outcomes and effectiveness of care, follow-up counseling,
discharge planning, and appropriate posttest referrals are the major components of this phase.
Abnormal Test Results
Report and interpret test outcomes correctly. Abnormal test patterns or trends can sometimes provide more useful
information than single test outcome deviations. Conversely, single test results can be normal in patients with a proven
disease or illness.
1. Recognize abnormal test results and consider the implications for the patient in both the acute and the chronic
stages of the disease as well as during screening.
2. The greater the degree of test abnormality, the more likely the outcome will be more serious.
3. Consider the role of drugs when tests are abnormal. Use of OTC drugs, vitamins, iron, and other minerals may
produce false-positive or false-negative test results. Patients often do not disclose all medications they use, either
unintentionally or deliberately. Commonly prescribed drugs that most often affect laboratory test outcomes include
anticoagulants, anticonvulsants, antibiotic or antiviral agents, oral hypoglycemics, hormones, and psychotropic
drugs. Consult a pharmacist or Physicians Desk Reference (PDR) source about drugs the patient is taking (eg,
current literature search, computerized data, or manufacturer's drug insert sheet) (see Appendix J). Be aware that
patients who are addicted to drugs or alcohol may not provide accurate, reliable information about their use of
these agents. In the same vein, sometimes athletes may not disclose their use of performance-enhancing drugs.
4. Consider biocultural variations when interpreting test results. See Table 1.8 for examples of some common
variations.

Table 1.8 Biocultural Considerations
Diagnostic Test

Biocultural Variation

Orthopedic x-rays

Body proportions and tendencies: African American people exhibit longer arms and
legs and shorter trunks than Caucasians. African American women tend to be wider
shouldered and more narrow hipped, but with more abdominal adipose tissue than
Caucasian women. Caucasian men tend to exhibit more abdominal adipose tissue
than do African American men. Native Americans and Asian Americans have larger
trunks and shorter limbs than do African American and Caucasian people. Asian
American people tend to be wider hipped and more narrow shouldered than do other
peoples.
African American men have the densest bones, followed by African American women
and Caucasian men, who have similar bone densities. Caucasian women have the
least dense bones. Chinese, Japanese, and Inuit bone density is less than that of
Caucasian Americans. Additionally, bone density decreases with age.
G6PD deficiency may be the cause of hemolytic disease of newborns in Asian
Americans and those of Mediterranean descent. Three G6PD variants occur
frequently: type A is common in African Americans (10% of males); the
Mediterranean type is common in Iraqis, Kurds, Lebanese, and Sephardic Jews; and
the Mahedial type is common in Southeast Asians (22% of males).
African American and Caucasian ethnic groups have similar cholesterol levels at
birth. During childhood, African American people develop higher levels than do
Caucasian people; however, African American adults have lower cholesterol levels
than do Caucasian adults.
The normal hemoglobin level for African American people is 1 g lower than that for
other groups. Given similar socioeconomic conditions, Asian Americans and
Mexican Americans have hemoglobin/hematocrit levels higher than those of
Caucasian people.
Sickle cell anemia affects millions of people throughout the world. It is particularly
common among people whose ancestors come from sub-Saharan Africa;
Spanish-speaking regions (South America, Cuba, Central America), Saudi Arabia,
India, and Mediterranean countries, such as Turkey, Greece, and Italy. In the United
States, it affects approximately 72,000 people, most of whose ancestors come from
Africa. The disease occurs in approximately 1 in every 1,000 to 1,400 Hispanic
American births. Approximately 2 million Americans, or 1 in 12 African Americans,
carry the sickle cell trait.

Bone density
measurements

Test for
glucose-6-phosphate
dehydrogenase (G6PD)
deficiency
Cholesterol levels

Hemoglobin/hematocrit
levels

Sickle cell anemia

Clinical Alert
1. Correct test interpretation also requires knowledge of all medications the patient is taking.
2. Support the patient and his or her significant others in understanding and coping with positive or negative test
outcomes.
3. Recognize that “panic values” may pose an immediate threat to the patient's health status. Report these findings
to the attending physician or other designated person immediately. Carefully document results and actions taken
as soon as possible.
4. Nearly all tests have limitations. Some tests cannot predict future outcomes or events. For example, an ECG
cannot predict a future myocardial infarction; it can merely tell what has already occurred. No test is absolute.
5. Devastating physical, psychological, and social consequences can result from being misdiagnosed with a serious
disease because of false-positive or false-negative test results. Major alterations in lifestyles and relationships
without just cause can be a consequence of these clinical aberrations (eg, misdiagnosis of HIV or syphilis).
Follow-Up Counseling
1. Counsel the patient regarding test outcomes and their implications for further testing, treatment, and possible
lifestyle changes. Provide time for the patient to ask questions and voice concerns about the entire testing process.
2. Test outcome interpretation involves reassessment of interfering factors and patient compliance if the results
significantly deviate from normal and previous results.
3. No test is perfect; however, the greater the degree of abnormality indicated by the test result, the more likely it is
that this outcome deviation is significant or represents a real disorder.
4. Notify the patient about test results after consultation with the clinician. Treatment may be delayed if test results are
misplaced or not communicated in a timely manner.
5. Help patients interpret the results of community-based testing.
6. Identify differences in the patient's view of the situation, the clinician's views about tests and disease, and the
health care team's perceptions.
7. When providing genetic counseling, the clinician needs to be sensitive to the implications of genetic or metabolic
disorders. Informing the patient or family about the genetic defect requires special training in genetic science, family
coping skills, and an understanding of legal and ethical issues. Confidentiality and privacy of information are vital.
8. Be familiar with crisis intervention skills for patients who experience difficulty dealing with the posttest phase.
9. Encourage the patient to take as much control of the situation as possible.
10. Recognize that the different stages of behavioral responses may last several weeks.

Monitoring for Complications
Observe for complications or other risks, and take appropriate measures to prevent or deal with them in a safe patient
environment.
1. The most common complications after invasive procedures are bleeding, infection (frequently a later complication),
respiratory difficulties, perforation of organs, and adverse effects of conscious sedation and local anesthesia.
Watch for related signs and symptoms such as redness, swelling, skin irritation, pain or tenderness, dyspnea,
abnormal breath sounds, cyanosis, decreased or increased pulse rate, blood pressure deviations (eg,
hypertension, hypotension), laryngospasm, agitation or combative behavior, pallor, and complaints of dizziness. If
adverse reactions or events occur, contact the physician immediately and initiate treatment as soon as possible.
2. Posttest assessments include evaluation of patient behaviors, complaints, activities, and compliance within the
emotional, physical, psychosocial, and spiritual dimensions. Alterations in any of these domains may indicate a
need for interventions appropriate to the dimension affected.
3. Older patients and children may require closer, more lengthy monitoring and observation. For example, invasive
procedure sites should be observed and assessed for potential bleeding and circulatory problems in the immediate
postprocedure phase and for infection as a later event (possibly several days later).
4. Patients who receive sedation, drugs, contrast media (eg, iodine, barium), or radioactive substances must be
evaluated and treated according to established protocols (see Appendix C and Chapter 9 and Chapter 10).
5. Infection control measures with standard precautions and aseptic techniques must be observed.
Test Result Availability
Collaborate with other disciplines to ensure that test results are made available to the clinician, patient, and staff as soon
as possible. Time-critical information is of limited value if it is delayed or not received. Even though computerized
communication technologies contribute to faster information delivery, clinicians are often left waiting for crucial clinical
data. Using facsimile (fax) machines, computers, and wireless networks properly can expedite the reporting of vital
patient data to the health care provider so that treatment can begin without delay.

Clinical Alert
The issue of confidentiality demands that access to records and information should be on a strict need-to-know basis
with secure and protected access available to select individuals.
Referral and Treatment
Referrals for further testing and beginning treatment are a part of the collaborative process. For example, the clinician
refers patients with abnormal Pap smear results to the specialist for colposcopy, loop electrocautery excision procedure
(LEEP), or cervical or endometrial biopsy. The clinician refers the patient for genetic counseling and dietary therapy for
genetic disorders such as phenylketonuria (PKU) cholesterol in the newborn.
Follow-Up Care
Follow-up care should be consistent and should provide clearly understood discharge instructions. Emphasize the
importance of and protocols for follow-up visits if these are ordered. Schedule ordered follow-up visits as appropriate.
Follow established protocols for discharge to home after testing is completed. For complex procedures that are invasive
or require sedation, be certain that a responsible individual escorts the patient home. Provide specific instructions
regarding infection control, barium elimination, iodine sensitivity, and resuming pretest activities. Have the patient repeat
this information back to the person providing the information to ensure that it has been understood. Plan time for
listening, support, discussion, and problem solving according to the patient's needs and requests. Follow-up by phone
may be done after discharge if indicated.
Documentation, Record Keeping, and Reporting
Record information about all phases of the diagnostic testing process in the patient's health care record. Accurately
document diagnostic activities and procedures during the pretest, intratest, and posttest phases because of legal,
budgetary, reimbursement, and diagnostic-related grouping (DRG) and common practice terminology (CPT) code
implications and constraints.
The patient's health care record is the only way to validate the need for diagnostic care, the quality and type of care
given, and the patient's response to the care and to ensure that current standards of medical and nursing care and
diagnostic testing are being met. The medical record may also be the basis for reimbursement for diagnostic tests by
Medicare (government), or private insurance programs. Accuracy, completeness, objectivity, and legibility are of utmost
importance in the documentation process. Documentation for laboratory and diagnostic testing includes recording all
pretest, intratest, and posttest care:
1. Document that the purpose, side effects, risks, and expected results and benefits, as well as alternative methods,
have been explained to the patient, and note who gave the explanation. Include information about medications, IV
conscious sedation, start and end times, and patient responses. Describe allergic or adverse reactions (see
Appendix B). Record data regarding disposition of specimens as well as information about follow-up care and
discharge instructions.
2. Document the patient's reasons for refusing a test along with any other pertinent information about the situation and
who was given this report.

3. Maintain records of laboratory and diagnostic test data. Frequently, these records are transferred onto compact
record storage systems such as microfilm or computer disks. For example, when an individual tests positive for HIV,
it is necessary to review donor records at blood donor centers to determine whether the individual ever donated
blood. If the infected person donated blood, the recipients of those blood components must be contacted and
informed of the situation. This process is called “look back.” Because many years may pass between donation and
transfusion and the time the donor tests HIV positive, medical history records of blood donors must be stored
indefinitely.
4. Indicate the time, day, month, and year of entries. This information can assume great importance in the office or
clinic setting when charts become very lengthy. Enter appropriate assessment data and note the patient's concerns
and questions that help to define the nursing diagnosis and focus for care planning. Document specific teaching
and preparation of the patient before the procedure. Avoid generalizations.
5. When an interpreter is present, document the name and relationship to the patient. Record that patient consent to
give confidential test information through an interpreter was obtained before revealing the information. Record any
deviations from basic witnessed consent policies (eg, illiteracy, non–English-speaking client, sedation immediately
before the request for consent signature, consent per telephone); include nurse measures employed to obtain
appropriate consent for the procedure.
6. Record that the preparation, side effects, expected results, and interfering factors have been explained. Document
the information given and the patient's response to that information. Keep a record of all printed and written
instructions. Record medications, treatments, food and fluids, intake status, beginning and end of specimen
collection and procedure times, outcomes, and the patient's condition during all phases of diagnostic care. If the
patient does not appear for testing, document this fact; include any follow-up discussion with the patient.
Completely and clearly describe side effects, symptoms, adverse reactions, and complications along with follow-up
care and instructions for posttest care and monitoring.
7. Record the patient's refusal to undergo diagnostic tests. Note the reasons, using the patient's own words if
possible. Document significant noncompliant behaviors such as refusal or inability to fast or to restrict or increase
fluid or food intake, incomplete timed specimens, inadequate or improperly self-collected specimens, and missed or
canceled test appointments. Place copies of letters sent in the patient's chart.
8. Reporting includes patient notification regarding test outcomes in a timely fashion and documentation that the
patient or family has been notified regarding test results. Document follow-up patient education and counseling.
9. Report results to designated professionals. Report critical (“panic”) values immediately, and document to whom
results were reported, orders received, and urgent treatments initiated.
10. Report all communicable diseases to appropriate agencies.
11. Report and document situations that are mandatory by state statute (eg, suspected elder abuse, child abuse as
evidenced by x-rays).
Reporting infectious diseases and outbreaks to state and federal governments is part of record keeping. Chart 1.4 and
Chart 1.5 are examples of one state's (Maryland) required reporting. Check with your individual state or province for
specific guidelines.

Chart 1.4 Diseases and Conditions Reportable by Health Care Providers and Others

Acquired immunodeficiency syndrome
(AIDS)

Legionellosis

Poliomyelitis *

Leprosy

Psittacosis

Leptospirosis

Rabies *

Lyme disease

Rocky Mountain spotted fever

Malaria

Rubella (German measles) and
congenital rubella syndrome *

Amebiasis
Animal bites *
Anthrax *
Botulism *
Measles (rubeola) *
Brucellosis

Salmonellosis

Chancroid

Meningitis (viral, bacterial, parasitic,
and fungal)
Septicemia in newborns

Cholera *

Meningococcal disease

Shigellosis

Diphtheria *

Mumps (infectious parotitis)

Syphilis

Encephalitis

Mycobacteriosis other than
tuberculosis and leprosy

Tetanus

Gonococcal infection

Trichinosis
Pertussis *

Haemophilus influenzae type b invasive
Tuberculosis
disease *
Pertussis vaccine adverse reactions
Tularemia *
Hepatitis, viral (A, B, C, all other types Plague *
and undetermined)
Typhoid fever (case or carrier) *
Kawasaki syndrome
*Reportable immediately by telephone.
From State of Maryland Department of Health and Mental Hygiene. Epidemiology and Disease Control Program.
(Reviewed: December 2002.)

Chart 1.5 Diseases and Conditions Reportable by Laboratory Directors

Amebiasis

Microsporidiosis

Anthrax

Mumps

Bacteremia in newborns

Pertussis

Botulism

Plague

Brucellosis

Poliomyelitis

Campylobacter infection

Psittacosis

CD4+ count, if <200/mm3 1

Q fever

Chlamydia infection

Rabies

Cholera

Ricin toxin

Coccidiodomycosis

Rocky Mountain spotted fever

Cryptosporidiosis

Rubella and congenital rubella syndrome

Cyclosporiasis

Salmonellosis (nontyphoid fever types)

Dengue fever

Shiga-like toxin production

Diphtheria

Shigellosis

Ehrlichiosis

Smallpox and other orthopox viruses

Encephalitis, infectious

Staphylococcal enterotoxin

E. coli O157:H7 infection

Streptococcal invasive disease, group A 2

Giardiasis

Streptococcal invasive disease, group B 2

Gonorrhea

Streptococcus pneumonia, invasive disease 2

Haemophilus influenza, invasive disease 1

Syphilis

Hansen's disease (leprosy)

Trichinosis

Hantavirus infection

Tularemia

Hepatitis, viral, types A, B, C, & other types

Typhoid fever

HIV infection 1

Varicella (chickenpox), fatal cases only

Isosporiasis

Vibriosis, noncholera 3

Legionellosis

Viral hemorrhagic fever (all types)

Leptospirosis

Yellow fever

Lyme disease

Yersiniosis

Malaria
Measles
Meningococcal invasive disease 2
Meningitis, infectious
1 Reportable by unique patient identifying number;
2 invasive disease means a disease in which an organism is detected in a specimen taken from a normally sterile body
site;

1 Reportable by unique patient identifying number;
2 invasive disease means a disease in which an organism is detected in a specimen taken from a normally sterile body
site;
3 need not be reported if found in a specimen obtained from a patient's teeth, gingival tissues, or oral mucosa.
(See the Annotated Code of Maryland, Health-General Article §18-205, for further reporting requirements.)
From State of Maryland Department of Health and Mental Hygiene Epidemiology and Disease Control Program.
(Reviewed: December 2002.)

Guidelines for Disclosure
Follow agency guidelines for disclosure. Ethical standards may be a source of conflict and anxiety when the professional
clinician is acting in the role of patient advocate. Recommended guidelines for telling a patient about test results can
alleviate some of this frustration. Under normal circumstances, the patient has the right to be informed of test results.
Although the clinician who orders the test is responsible for providing initial test result information, other designated
individuals may need to facilitate and support the patient's right to know information about their health status.
In cases in which the patient brings family and significant others together to inform them about test results,
communication becomes open and shared. This prevents the so-called conspiracy of silence, in which individuals in the
scenario withhold information because they feel they are protecting the patient or family or because they do not know
how to deal with the situation.
Patient Responses to Expected or Unexpected Outcomes
Develop crisis intervention skills to use when communicating with the patient who experiences difficulty dealing with
abnormal test results or confirmation of disease or illness.
1. Encourage the patient to take as much control of the situation as possible.
2. Recognize that the different stages of behavioral responses to negative results may last several weeks or longer.
3. Monitor changes in patient affect, mood, behaviors, and motivation. Do not assume that persons who initially have a
negative perception of their health (eg, denial of diabetes) will not be able to integrate better health behaviors into
daily life once they accept the diagnosis.
4. Use the following strategies to lessen the impact of a threatening situation:
a. Offer appropriate comfort measures.
b. Allow patients to work through feelings of anxiety and depression. At the appropriate time, reassure them that
these feelings and emotions are normal initially. Be more of a therapeutic listener than a talker.
c. Assist the patient and family in making necessary lifestyle and self-concept adjustments through education,
support groups, and other means. Emphasize that risk factors associated with certain diseases can be reduced
through lifestyle changes. Be realistic.
It is better to introduce change slowly rather than trying to promote adjustments on a grand scale in a short period of time
( Table 1.9).

Table 1.9 Behavioral Responses
Immediate Response

Secondary Response

Acute emotional turmoil, shock, disbelief
about diagnosis, denial
Anxiety will usually last several days until
the person assimilates the information.

Insomnia, anorexia, difficulty concentrating, depression, difficulty in performing
work-related responsibilities and tasks
Depression may last several weeks as the person begins to incorporate the
information and to participate realistically in a treatment plan and lifestyle
adaptation.

Expected and Unexpected Outcomes
Evaluate outcomes using the following steps:
1. Learn the normal or reference values and expected outcomes of the test. The patient or his or her significant others
should be able to describe the purpose of the test and the testing process and should properly perform expected
activities associated with testing. Offer assistance if necessary. If test outcomes are abnormal, the patient should
be encouraged to comply with repeat testing and to introduce appropriate lifestyle changes realistically. Deal with
anxiety and fears in a timely manner. Refer the patient to appropriate counseling resources if indicated. Above all,
do not dismiss the patient's feelings and concerns casually.
2. Compare normal values with abnormal results and apply these comparisons to the patient's situation. Sometimes,
desired outcomes cannot be achieved. For example, the patient cannot, for various reasons, fully participate in the
teaching/learning process or the actual testing itself. Recommendations for follow-up care and lifestyle changes
may not be able to be followed. Verbal and nonverbal cues can sometimes provide reasons (eg, Alzheimer's
disease, physical limitations) for this inability. In another instance, the patient might be noncompliant with pretest
preparations and posttest activities. Denial of the situation is frequently a reason, although there are many other
causes for noncompliance. Patients may refuse diagnostic testing because they feel the results may confirm their

3.

4.

5.
6.
7.

worst suspicions and fears.
Numerous and varied responses can be related to lack of appropriate problem-solving behaviors, inappropriate
behaviors, fears or denial, concern about potential complications, inability to cope with or take control of the
situation, depression or abnormal emotional patterns of response, and lack of support from significant others and
family. Perceptions of having experienced uncaring acts can lead to frustration, despair, and hopelessness on the
patient's part.
Adverse events (eg, perforation, anaphylaxis, death) and health hazards may occur as a result of diagnostic
procedures or problems with a medical device or product (eg, reactions to latex gloves or other latex-containing
medical devices). Health professionals are asked to monitor and voluntarily report faulty medical devices to the
U.S. Food and Drug Administration (FDA) so that action can be taken to protect the public. Reporting does not
necessarily constitute an admission that medical personnel or the product caused or contributed to the adverse
event.
Prompt action is necessary when results are abnormally high or low and are indicative of a serious situation (eg,
positive blood culture, abnormally elevated potassium level).
Modify, report, and collaborate with other clinicians when unexpected or abnormal values occur and when changes
in medical care may be necessary as a result of test outcomes.
Examples of expected and unexpected test outcomes follow in Table 1.10.
Table 1.10 Test Outcomes
Expected Outcomes

Unexpected Outcomes

Anticipated outcomes will be achieved.

Some anticipated outcomes may not be achieved, possibly because of
specific patient behaviors that interfere with care interventions (eg,
patient does not appear for testing appointment, patient did not fast or
withhold medication when directed before testing).
Inability to fully participate in teaching or learning process is evidenced
by verbal and nonverbal cues. Patient cannot properly perform
expected activities. Misinterpretation and misinformation of diagnostic
process results in panic, avoidance behaviors, and refusal to have tests
done.
Patient does not comply with test preparation guidelines and posttest
recommended lifestyle changes; hides test results; and minimizes or
exaggerates meaning of test outcomes.

Patient, family, and significant others
should be able to describe the testing
process and purpose and be able to
properly perform expected activities.
Information contributes to empowerment.
If test outcomes are abnormal, the
appropriate lifestyle changes will be
made, and the patient will adopt healthy
behaviors.
Does not develop complications and
remains free from injury.
If complications occur, they will be
optimally resolved. Signs of infection
treated immediately and infection
resolved.
Anxiety and fears will be alleviated and
will not interfere with the testing process.
The patient is helped to balance fears
with the recognition of the potential for
developing coping skills.
With support and education, able to
cope with test outcomes revealing a
chronic or life-threatening disease. Hope
is inspired or generated, and the patient
feels “cared for.”

Patient exhibits untoward signs and symptoms (eg, allergic response,
shock, bleeding, nausea, vomiting, retention of barium).
Complications are not fully resolved, health state is compromised, and
more extensive testing and care are needed.

Because of anxiety, fear, or uncertainty, the patient is unable to collect
specimens properly or to accurately comply with procedural steps. The
nurse is unable to calm and reassure the patient. Invasive tests may be
canceled if the patient is too anxious or fearful.
Lack of appropriate problem-solving behaviors, uncertainty or denial
about test outcomes, inability to cope with test outcomes, extreme
depression and abnormal patterns of responses, and refusal to take
control of the situation or to cooperate with prescribed regimens.
Anxiety, grief, guilt, or sense of social stigma about the illness persists.
Uses alcohol or drugs. Caregivers are seen as uncaring.

IMPORTANCE OF COMMUNICATION
At the heart of informed care is the ability to communicate effectively. Frequently, communication must take place within
a compressed time frame because of time constraints. Thus, the importance of communicating effectively cannot be
emphasized enough. Effective communication is the key to achieving desired outcomes, preventing misunderstanding
and errors, and helping patients feel secure and connected to the diagnostic process. One must always keep in mind that
the human person is an integration of body, mind, and spirit and that these three entities are intimately bound together to
make each person unique. Skillful assessment of physical, emotional, psychosocial, and spiritual dimensions provides a
sound database from which to plan communication and teaching/instruction strategies.
Individuals have different needs and changing capacities for learning as they progress from child to adult to older adult. It
is important for the clinician to know the different developmental levels and stages and the ways in which clear
communication can be achieved at any level.
For the pediatric patient, teaching tools might include tours of the diagnostic area, play therapy, films or videos, models
of equipment that the child can touch or manipulate, and written materials and pictures appropriate to the child's
developmental stage. Shorter attention spans and the unpredictable nature of children can make teaching a challenge in
this population. Mentally retarded or mentally ill patients may need significant others close by who can guide
communication between caretaker and patient. Gentle, simple, nurturing behaviors usually work well with children and
developmentally challenged individuals.

Adolescents may be at the stage of developing their own unique identity as they move toward adulthood. Teaching may
be more effective without parents present; however, it is important to include parents at some point. Drawings,
illustrations, or videos are helpful. Because body image is very important at this stage, honest, supportive behaviors are
necessary, especially if some alteration in physical appearance will be necessary (eg, removal of jewelry, no makeup
allowed).
The opportunity to participate actively and to ask questions is important for adults. They bring to the communication
process their lifetime of perceptions and experiences. This can be a proverbial “double-edged sword.” Listening well to
verbal cues as well as paying attention to nonverbal messages cannot be overemphasized. For example, interacting with
patients who have Alzheimer's disease can present special challenges. The presence of a significant other who has
experience communicating with this patient can be the key to performing a successful procedure.
Provide an environment that is quiet, private, and free of distractions to promote dialogue and communication. Ask by
what name or title the patient wishes to be addressed. Referring to a patient as a room number, a procedure, or a
disease is demeaning and inexcusable; it reduces the patient to the level of an object rather than a person.
Nonverbal communication behaviors such as proper eye contact, firm handshake, sense of respect, and appropriate
humor can reduce anxiety. Do not dismiss the power of touch, the sense of “making time” for the patient, and the use of
appropriate and positive verbal cues. The greater part of communication (>70%) is perceived through body language. If
words don't match body language and behaviors, patients will react to the body language they observe as their primary
frame of reference. Negative communication by caregivers often is experienced by patients as an uncaring attitude and
results in a sense of discouragement.
Every person engaged in the entire process of testing is a link in the ongoing communication continuum. This continuum
is only as effective as the weakest link that joins all activities and all communication together.

CONCLUSION
As professionals, we need to remember that patients are people just like us. These individuals present with their
perceptions, worries, and anxieties regarding the diagnostic process and what their illness means to them and their loved
ones, what strategies they use for coping, what resources are available for their use, and what other knowledge they
have about themselves. As clinicians and patient advocates, we must be willing to “take on the mind” of another—that is,
to identify with the patient's point of view as much as possible and to show empathy. Once we reach that point, we can
then begin to understand and communicate with each other at the deeper levels necessary for a therapeutic relationship
to occur.
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Fischbach FT: Quick Reference to Common Laboratory and Diagnostic Tests, 3rd ed. Philadelphia, Lippincott Williams & Wilkins, 2002
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Frizzell J, Credit CE: Avoiding laboratory test pitfalls. Am J Nurs 98(2): 34–38, 1998
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2 Blood Studies; Hematology and Coagulation
A Manual of Laboratory and Diagnostic Tests

2
Blood Studies; Hematology and Coagulation
OVERVIEW OF BASIC BLOOD HEMATOLOGY AND COAGULATION TESTS
Composition of Blood
Blood Tests
BLOOD SPECIMEN COLLECTION PROCEDURES
Capillary Puncture (Skin Puncture)
Venipuncture
NOTE
NOTE
Bone Marrow Aspiration
BASIC BLOOD TESTS
Hemogram
Complete Blood Count (CBC)
TESTS OF WHITE BLOOD CELLS
White Blood Cell Count (WBC; Leukocyte Count)
Differential White Blood Cell Count (Diff; Differential Leukocyte Count)
NOTE
Segmented Neutrophils (Polymorphonuclear Neutrophils, PMNs, Segs, Polys)
Eosinophils
Basophils
Monocytes (Monomorphonuclear Monocytes)
Lymphocytes (Monomorphonuclear Lymphocytes); CD4, CD8 Count; Plasma Cells
Lymphocyte Immunophenotyping (T and B Cells)
STAINS FOR LEUKEMIAS
Sudan Black B (SBB) Stain
Periodic Acid–Schiff (PAS) Stain
Terminal Deoxynucleotidyl Transferase (TDT) Stain
Leukocyte Alkaline Phosphatase (LAP) Stain
Tartrate-Resistant Acid Phosphatase (TRAP) Stain
TESTS OF RED BLOOD CELLS
Red Blood Cell Count (RBC; Erythrocyte Count)
Hematocrit (Hct); Packed Cell Volume (PCV)
Hemoglobin (Hb)
Red Blood Cell Indices
Mean Corpuscular Volume (MCV)
Mean Corpuscular Hemoglobin Concentration (MCHC)
Mean Corpuscular Hemoglobin (MCH)
Red Cell Size Distribution Width (RDW)
Stained Red Cell Examination (Film; Stained Erythrocyte Examination)
NOTE
Reticulocyte Count
Sedimentation Rate (Sed Rate); Erythrocyte Sedimentation Rate (ESR)
TESTS FOR PORPHYRIA
Erythropoietic Porphyrins; Free Erythrocyte Protoporphyrin (FEP)
Porphyrins; Fractionation of Erythrocytes and of Plasma
ADDITIONAL TESTS FOR HEMOLYTIC ANEMIA
Pyruvate Kinase (PK)
Erythrocyte Fragility (Osmotic Fragility and Autohemolysis)
Glucose-6-Phosphate Dehydrogenase (G6PD)
Heinz Bodies; Heinz Stain; Glutathione Instability
2,3-Diphosphoglycerate (2,3-DPG)
IRON TESTS
Iron (Fe), Total Iron-Binding Capacity (TIBC), and Transferrin Tests
Ferritin
Iron Stain (Stainable Iron in Bone Marrow; Prussian Blue Stain)
TESTS FOR HEMOGLOBIN DISORDERS
Hemoglobin Electrophoresis
Clinical Alert
Fetal Hemoglobin (Hemoglobin F; Alkali-Resistant Hemoglobin)
Hemoglobin A2 (Hb A2)
Hemoglobin S (Sickle Cell Test; Sickledex)
Methemoglobin (Hemoglobin M)
Sulfhemoglobin
Carboxyhemoglobin; Carbon Monoxide (CO)
Myoglobin (Mb)
Haptoglobin (Hp)
Bart's Hemoglobin
Paroxysmal Nocturnal Hemoglobinuria (PNH) Test; Acid Hemolysis Test; Ham's Test
OTHER BLOOD TESTS FOR ANEMIA
Vitamin B12 (VB12)
Folic Acid (Folate)
Erythropoietin (Ep)
TESTS OF HEMOSTASIS AND COAGULATION

Hypercoagulability States
Disorders of Hemostasis
Clinical Alert
Clinical Alert
Tests for Disseminated Intravascular Coagulation (DIC)
Bleeding Time (Ivy Method; Template Bleeding Time)
Platelet Count; Mean Platelet Volume (MPV)
Platelet Aggregation
Thrombin Time (TT); Thrombin Clotting Time (TCT)
Partial Thromboplastin Time (PTT); Activated Partial Thromboplastin Time (APTT)
NOTE
Activated Coagulation Time (ACT)
Prothrombin Time (Pro Time; PT)
Coagulant Factors (Factor Assay)
Plasminogen (Plasmin; Fibrinolysin)
Fibrinolysis (Euglobulin Lysis Time; Diluted Whole Blood Clot Lysis)
Fibrin Split Products (FSPs); Fibrin Degradation Products (FDPs)
D-Dimer
Fibrinopeptide A (FPA)
Prothrombin Fragment (F1 + 2)
Fibrin Monomers (Protamine Sulfate Test; Fibrin Split Products)
Fibrinogen
Protein C (PC Antigen)
NOTE
NOTE
Protein S
Antithrombin III (AT-III; Heparin Cofactor Activity)
BIBLIOGRAPHY

OVERVIEW OF BASIC BLOOD HEMATOLOGY AND COAGULATION TESTS
Composition of Blood
The average person circulates about 5 L of blood (1/13 of body weight), of which 3 L is plasma and 2 L is cells. Plasma
fluid derives from the intestines and lymphatic systems and provides a vehicle for cell movement. The cells are produced
primarily by bone marrow and account for blood “solids.” Blood cells are classified as white cells (leukocytes), red cells
(erythrocytes), and platelets (thrombocytes). White cells are further categorized as granulocytes, lymphocytes,
monocytes, eosinophils, and basophils.
Before birth, hematopoiesis occurs in the liver. In midfetal life, the spleen and lymph nodes play a minor role in cell
production. Shortly after birth, hematopoiesis in the liver ceases, and the bone marrow is the only site of production of
erythrocytes, granulocytes, and platelets. B lymphocytes are produced in the marrow and in the secondary lymphoid
organs; T lymphocytes are produced in the thymus.
Blood Tests
Tests in this chapter are basic screening tests that address disorders of hemoglobin (Hb) and cell production
(hematopoiesis), synthesis, and function. Blood and bone marrow examinations constitute the major means of
determining certain blood disorders (anemias, leukemia and porphyrias disorders, abnormal bleeding and clotting),
inflammation, infection and inherited disorders of red blood cells, white blood cells, and platelets. Specimens are
obtained through capillary skin punctures (finger, toe, heel), dried blood samples, arterial or venous sampling, or bone
marrow aspiration. Specimens may be tested by automated or manual hematology instrumentation and evaluation.

BLOOD SPECIMEN COLLECTION PROCEDURES
Proper specimen collection presumes correct technique and accurate timing when necessary. Most hematology tests use
liquid ethylenediaminetetraacetic acid (EDTA) as an anticoagulant. Tubes with anticoagulants should be gently but
completely inverted end over end 7 to 10 times after collection. This action ensures complete mixing of anticoagulants
with blood to prevent clot formation. Even slightly clotted blood invalidates the test, and the sample must be redrawn.
For plasma coagulator studies, such as prothrombin time (PT) and partial thromboplastin time (PTT), the tube must be
allowed to fill to its capacity or an improper blood-to-anticoagulant ratio will invalidate coagulator results. Invert 7 to 10
times to prevent clotting.
Capillary Puncture (Skin Puncture)
Capillary blood is preferred for a peripheral blood smear and can also be used for other hematology studies.
Procedure
1. Observe standard precautions (see Appendix A). Check for latex allergy. If allergy is present, do not use
latex-containing products (see Appendix B).
2. Obtain capillary blood from fingertips or earlobes (adults) or from the great toe or heel (infants).
3. Disinfect puncture site, dry the site, and puncture skin with sterile disposable lancet no deeper than 2 mm. If
povidone-iodine is used, allow to dry thoroughly.
4. Wipe away the initial drop of blood. Collect subsequent drops in a microtube or prepare a smear directly from a

drop of blood.

Clinical Alert
1. Do not squeeze the site to obtain blood because this alters blood composition and invalidates test values.
2. Warming the extremity or placing it in a dependent position may facilitate specimen collection.
Interventions
Pretest Patient Care
1. Instruct patient about purpose and procedure of test.
2. Follow Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1.
2.
3.
4.
5.

Apply small dressing or adhesive strip to site.
Evaluate puncture site for bleeding or oozing.
Apply compression or pressure to the site if it continues to bleed.
Evaluate patient's medication history for anticoagulation or acetylsalicylic acid (ASA)-type drug ingestion.
Follow Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
Dried Blood Spot
In this method, a lancet is used, and the resulting droplets of blood are collected by blotting them with filter paper
directly. Check the stability of equipment and integrity of supplies when doing a finger stick. If provided, check the
humidity indicator patch on the filter paper card. If the humidity circle is pink, do not use this filter paper card. The
humidity indicator must be blue to ensure specimen integrity.
After wiping the first drop of blood on the gauze pad, fill and saturate each of the circles in numerical order by blotting
the blood droplet with the filter paper. Do not touch the patient's skin to the filter paper; only the blood droplet should
come in contact with the filter paper. If an adult has a cold hand, run warm water over it for approximately 3 minutes.
The best flow occurs when the arm is held downward, with the hand below heart level, making effective use of gravity.
If there is a problem with proper blood flow, milk the finger with gentle pressure to stimulate blood flow or attempt a
second finger stick; do not attempt more than two. When the blood circles penetrate through to the other side of the
filter paper, the circles are fully saturated.
Venipuncture
Venipuncture allows procurement of larger quantities of blood for testing. Usually, the antecubital veins are the veins of
choice because of ease of access. Blood values remain constant no matter which venipuncture site is selected, so long
as it is venous and not arterial blood.
1. Observe standard precautions (see Appendix A). If latex allergy is suspected, use latex-free supplies and
equipment (see Appendix B).
2. Position and tighten a tourniquet on the upper arm to produce venous congestion.
3. Ask the patient to close the fist in the designated arm. Select an accessible vein.
4. Cleanse the puncture site and dry it properly with sterile gauze. Povidone-iodine must dry thoroughly.
5. Puncture the vein according to accepted technique. Usually, for an adult, anything smaller than a 21-gauge needle
might make blood withdrawal more difficult. A Vacutainer system syringe or butterfly system may be used.
6. Once the vein has been entered by the collecting needle, blood will fill the attached vacuum tubes automatically
because of negative pressure within the collection tube.
7. Remove the tourniquet before removing the needle from the puncture site or bruising will occur.
8. Remove needle. Apply pressure and sterile dressing strip to site.
9. The preservative or anticoagulant added to the collection tube depends on the test ordered. In general, most
hematology tests use EDTA anticoagulant. Even slightly clotted blood invalidates the test, and the sample must be
redrawn.
10. Take action to prevent these venipuncture errors:
a. Pretest errors
1. Improper patient identification
2. Failure to check patient compliance with dietary restrictions
3. Failure to calm patient before blood collection
4. Use of wrong equipment and supplies
5. Inappropriate method of blood collection
b. Procedure errors
1. Failure to dry site completely after cleansing with alcohol
2. Inserting needle with bevel side down
3. Using too small a needle, causing hemolysis of specimen
4. Venipuncture in unacceptable area (eg, above an intravenous [IV] line)
5. Prolonged tourniquet application
6. Wrong order of tube draw
7. Failure to mix blood immediately that is collected in additive-containing tubes
8. Pulling back on syringe plunger too forcefully

9. Failure to release tourniquet before needle withdrawal
c. Posttest errors
1. Failure to apply pressure immediately to venipuncture site
2. Vigorous shaking of anticoagulated blood specimens
3. Forcing blood through a syringe needle into tube
4. Mislabeling of tubes
5. Failure to label specimens with infectious disease precautions as required
6. Failure to put date, time, and initials on requisition
7. Slow transport of specimens to laboratory

NOTE
A blood pressure cuff inflated to a point between systolic and diastolic pressure values can be used.

NOTE
The Vacutainer system consists of vacuum tubes (Vacutainer tubes), a tube holder, and a disposable multisample
collecting needle.
Interventions
Pretest Patient Care
1.
2.
3.
4.

Instruct patient regarding sampling procedure. Assess for circulation or bleeding problems and allergy to latex.
Reassure patient that mild discomfort may be felt when the needle is inserted.
Place the arm in a fully extended position with palmar surface facing upward (for antecubital access).
If withdrawal of the sample is difficult, warm the extremity with warm towels or blankets. Allow the extremity to
remain in a dependent position for several minutes before venipuncture.

Clinical Alert
In patients with leukemia, agranulocytosis, or lowered resistance, finger-stick and earlobe punctures are more likely to
cause infection and bleeding than venipunctures. Should a capillary sample be necessary, the cleansing agent should
remain in contact with the skin for at least 5 to 10 minutes. Povidone-iodine is the cleansing agent of choice. It should
be allowed to dry. It may then be wiped off with alcohol and the site dried with sterile gauze before puncture.
Posttest Patient Aftercare
1. If oozing or bleeding from the puncture site continues for an unusually long time, elevate the area and apply a
pressure dressing. Observe the patient closely. Check for anticoagulant or ASA-type ingestion.
2. Be aware that the patient occasionally becomes dizzy, faint, or nauseated during the venipuncture. The
phlebotomist must be constantly aware of the patient's condition. If a patient feels faint, immediately remove the
tourniquet and terminate the procedure. If the patient is sitting, lower the head between the legs and instruct the
patient to breathe deeply. A cool, wet towel may be applied to the forehead and back of the neck, and, if necessary,
ammonia inhalant may be applied briefly. If the patient remains unconscious, notify a physician immediately.
3. Prevent hematomas by using proper technique (not sticking the needle through the vein), releasing the tourniquet
before the needle is withdrawn, applying sufficient pressure over the puncture site, and maintaining an extended
extremity until bleeding stops.

Clinical Alert
1. Never draw blood from the same extremity being used for IV medications, fluids, or transfusions. If no other site is
available, make sure the venipuncture site is below the site. Avoid areas that are edematous, are paralyzed, are
on the same side as a mastectomy, or have infections or skin conditions present. Venipuncture may cause
infection, circulatory impairment, or retarded healing.
2. Prolonged tourniquet application causes stasis and hemoconcentration and will alter test results.
Bone Marrow Aspiration
Bone marrow is located within cancellous bone and long bone cavities. It consists of a pattern of vessels and nerves,
differentiated and undifferentiated hematopoietic cells, reticuloendothelial cells, and fatty tissue. All of these are encased
by endosteum, the membrane lining the bone marrow cavity. After proliferation and maturation have occurred in the
marrow, blood cells gain entrance to the blood through or between the endothelial cells of the sinus wall.
A bone marrow specimen is obtained through aspiration or biopsy or needle biopsy aspiration. A bone marrow
examination is important in the evaluation of a number of hematologic disorders and infectious diseases. The presence
or suspicion of a blood disorder is not always an indication for bone marrow studies. A decision to employ this procedure
is made on an individual basis.
Sometimes, the aspirate does not contain hematopoietic cells. This “dry tap” occurs when hematopoietic activity is so
sparse that there are no cells to be withdrawn or when the marrow contains so many tightly packed cells that they cannot
be suctioned out of the marrow. In such cases, a bone marrow biopsy would be advantageous. Before the bone marrow
procedure is started, a peripheral blood smear should be obtained from the patient and a differential leukocyte count
done.

Reference Values
Normal See Table 2.1 for normal values
Table 2.1 Normal Values for Bone Marrow *
Formed Cell Elements

Normal Mean (%)

Range (%)

Undifferentiated cells
0.0
0.0–1.0
Reticulum cells
0.4
0.0–1.3
Myeloblasts
2.0
0.3–5.0
Promyelocytes
5.0
1.0–8.0
Myelocytes
Neutrophilic
12.0
5.0–19.0
Eosinophilic
1.5
0.5–3.0
Basophilic
0.3
0.0–0.5
Metamyelocytes
25.6
17.5–33.7
Neutrophilic
0.4
0.0–1.0
Eosinophilic
0.0
0.0–0.2
Segmented granulocytes
Neutrophilic
20.0
11.6–30.0
Eosinophilic
2.0
0.5–4.0
Basophilic
0.2
0.0–3.0
Monocytes
2.0
0–3
Lymphocytes
10.0
8–20
Megakaryocytes
0.4
0.0–3.0
Plasma cells
0.9
0.0–2.0
Erythroid series
Pronormoblasts
0.5
0.2–4.2
Basophilic normoblasts
1.6
0.24–4.8
Polychromatic normoblasts
10.4
3.5–20.5
Orthochromatic normoblasts
6.4
3.0–25
Promegaloblasts
0
0
Basophilic megaloblasts
0
0
Polychromatic megaloblasts
0
0
Orthochromatic megaloblasts
0
0
Myeloid: erythroid ratio (ratio of WBC to nucleated RBC)
2:1–4:1
(Slightly higher in infants)
*These values are only for adults, and should be used as a guideline. (Each laboratory should establish its own
reference range.)

Procedure
1. Follow standard precautions. Check for latex allergy; if allergy is present, do not use latex-containing products.
Position the patient on the back or side according to site selected. The posterior iliac crest is the preferred site in all
patients older than 12 to 18 months. Alternate sites include the anterior iliac crest, sternum, spinous vertebral
processes T10 through L4, the ribs, and the tibia in children. The sternum is not generally used in children because
the bone cavity is too shallow, the risk for mediastinal and cardiac perforation is too great, and the child may be
uncooperative.
2. Shave, cleanse, and drape the site as for any minor surgical procedure.
3. Inject a local anesthetic (procaine or lidocaine). This may cause a burning sensation. At this time, a skin incision of
3 mm is often made.
4. Remember that the physician introduces a short, rigid, sharp-pointed needle with stylet through the periosteum into
the marrow cavity.
5. Pass the needle-stylet combination through the incision, subcutaneous tissue, and bone cortex. The stylet is
removed, and 1 to 3 mL of marrow fluid is aspirated. Alert the patient that when the stylet needle enters the marrow,
he or she may experience a feeling of pressure. The patient may also feel moderate discomfort as aspiration is
done, especially in the iliac crest. Use the Jamshidi needle for biopsy, although you can also use the
Westerman-Jansen modification of the Vim-Silverman needle.
6. Remove the stylet and advance the biopsy needle with a twisting motion toward the anterosuperior iliac spine.
7. Rotate or “rock” the needle in several directions several times after adequate penetration of the base (3 cm) has
been achieved. This “frees up” the specimen. Slowly withdraw the needle once this is done.
8. Push the biopsy specimen out backward from the needle. Use it to make touch preparations or immediately place in
fixative. Make slide smears at the bedside.
9. Apply pressure to the puncture site until bleeding ceases. Dress the site.
10. Place specimens in biohazard bags, label properly, and route to the appropriate department.
Clinical Implications
1. A specific and diagnostic bone marrow picture provides clues to many diseases. The presence, absence, and ratio
of cells are characteristic of the suspected disease.
2. Bone marrow examination may reveal the following abnormal cell patterns:
a. Multiple myeloma, plasma cell myeloma, macroglobulinemia
b. Chronic or acute leukemias

c. Anemia, including megaloblastic, macrocytic, and normocytic anemias
d. Toxic states that produce bone marrow depression or destruction
e. Neoplastic diseases in which the marrow is invaded by tumor cells (metastatic carcinoma, myeloproliferative and
lymphoproliferative diseases); assists in diagnosis and staging
f. Agranulocytosis (a decrease in the production of white cells). This occurs when bone marrow activity is severely
depressed, usually as a result of radiation therapy or chemotherapeutic drugs. Implications for the patient focus
on the risk for death from overwhelming infection.
g. Platelet dysfunction
h. Some types of infectious diseases, especially histoplasmosis and tuberculosis
i. Deficiency of body iron stores, microcytic anemia
j. Lipid or glycogen storage disease
Interventions
Pretest Patient Care
1. Instruct the patient about the test procedure, purpose, benefits, and risks.
2. Ensure that a legal consent form is properly signed and witnessed. Bone marrow aspiration is usually
contraindicated in the presence of hemophilia and other bleeding dyscrasias. However, risk versus benefit may
dictate the choice made.
3. Reassure the patient that analgesics will be available if needed.
4. Be aware that bone marrow biopsies or aspirations can be uncomfortable. Squeezing a pillow may be helpful as a
distraction technique.
5. Observe standard precautions.

Clinical Alert
1. Complications can include bleeding and sternal fractures. Osteomyelitis or injury to heart or great vessels is rare
but can occur if the sternal site is used.
2. Manual and pressure dressings over the puncture site usually control excessive bleeding. Remove dressing in 24
hours. Redress site if necessary.
3. Fever, headache, unusual pain, or redness or pus at biopsy site may indicate infection (later event). Instruct
patient to report unusual symptoms to physician immediately.
Posttest Patient Aftercare
1. Monitor vital signs until stable and assess site for excess drainage or bleeding.
2. Recommend bed rest for 30 minutes; then normal activities can be resumed.
3. Administer analgesics for sedatives as necessary. Soreness over the puncture site for 3 to 4 days after the
procedure is normal. Continued pain may indicate fracture.
4. Interpret test outcomes and monitor appropriately.
5. Follow Chapter 1 guidelines for safe, effective, informed posttest care .

BASIC BLOOD TESTS
Hemogram
A hemogram consists of a white blood cell count (WBC), red blood cell count (RBC), hemoglobin (Hb), hematocrit (Hct),
red blood cell indices, and a platelet count. A complete blood count (CBC) consists of a hemogram plus a differential
WBC.
Complete Blood Count (CBC)
The CBC is a basic screening test and is one of the most frequently ordered laboratory procedures. The findings in the
CBC give valuable diagnostic information about the hematologic and other body systems, prognosis, response to
treatment, and recovery. The CBC consists of a series of tests that determine number, variety, percentage,
concentrations, and quality of blood cells:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.

White blood cell count (WBC): leukocytes fight infection
Differential white blood cell count (Diff): specific patterns of WBC
Red blood cell count (RBC): red blood cells carry O 2 from lungs to blood tissues and CO 2 from tissue to lungs
Hematocrit (Hct): measures RBC mass
Hemoglobin (Hb): main component of RBCs and transports O 2 and CO 2
Red blood cell indices: calculated values of size and Hb content of RBCs; important in anemia evaluations
Mean corpuscular volume (MCV)
Mean corpuscular hemoglobin concentration (MCHC)
Mean corpuscular hemoglobin (MCH)
Stained red cell examination (film or peripheral blood smear)
Platelet count (often included in CBC): thrombocytes are necessary for clotting and control of bleeding
Red blood cell distribution width (RDW): indicates degree variability and abnormal cell size.
Mean platelet volume (MPV): index of platelet production

These tests are described in detail in the following pages.

Normal Values for Hemogram
Age
WBC (× 10 3/mm 3 ) RBC (× 10 6/mm 3)
Birth–2 wk
9.0–30.0
4.1–6.1
2–8 wk
5.0–21.0
4.0–6.0
2–6 mo
5.0–19.0
3.8–5.6
6 mo–1 y
5.0–19.0
3.8–5.2
1–6 y
5.0–19.0
3.9–5.3
6–16 y
4.8–10.8
4.0–5.2
16–18 y
4.8–10.8
4.2–5.4
>18 y (males) 5.0–10.0
4.5–5.5
>18 y (females) 5.0–10.0
4.0–5.0
Age
MCH (pg/cell)
MCHC (g/dL)
Birth–2 wk
2–8 wk
2–6 mo
6 mo–1 y
1–6 y
6–16 y
16–18 y
>18 y

34–40
30–36
27–33
24–30
23–29
24–30
25–31
28–34

33–37
32–36
31–35
32–36
31–35
32–36
32–36
32–36

Hb (g/dL)

Hct (%)

MCV (fL)

14.5–24.5
12.5–20.5
10.7–17.3
9.9–14.5
9.5–14.1
10.3–14.9
11.1–15.7
14.0–17.4
12.0–16.0

44–64
98–112
39–59
98–112
35–49
83–97
29–43
73–87
30–40
70–84
32–42
73–87
34–44
75–89
42–52
84–96
36–48
84–96
Platelets (× 10 3 /mm 3) RDW (%) MPV (fL)
150–450
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
140–400
11.5–14.5 7.4–10.4

Interventions
Pretest Patient Care for Hemogram, CBC, and Differential (Diff) Count (All Components)
1. Explain test procedure. Explain that slight discomfort may be felt when skin is punctured. Refer to venipuncture
procedure for additional information.
2. Avoid stress if possible because altered physiologic status influences and changes normal hemogram values.
3. Select hemogram components ordered at regular intervals (eg, daily, every other day). These should be drawn
consistently at the same time of day for reasons of accurate comparison; natural body rhythms cause fluctuations in
laboratory values at certain times of the day.
4. Dehydration or overhydration can dramatically alter values; for example, large volumes of IV fluids can “dilute” the
blood, and values will appear as lower counts. The presence of either of these states should be communicated to
the laboratory.
5. Fasting is not necessary. However, fat-laden meals may alter some test results as a result of lipidemia.
Posttest Patient Aftercare for Hemogram, CBC, and Differential (Diff) Count (All Components)
1. Apply manual pressure and dressings to the puncture site on removal of the needle.
2. Monitor the puncture site for oozing or hematoma formation. Maintain pressure dressings on the site if necessary.
Notify physician of unusual problems with bleeding.
3. Resume normal activities and diet.
4. Bruising at the puncture site is not uncommon. Signs of inflammation are unusual and should be reported if the
inflamed area appears larger, if red streaks develop, or if drainage occurs.

Clinical Alert
NEVER apply a total circumferential dressing and wrap because this may compromise circulation and nerve function if
constriction, from whatever cause, occurs.

TESTS OF WHITE BLOOD CELLS
White Blood Cell Count (WBC; Leukocyte Count)
White blood cells (or leukocytes) are divided into two main groups: granulocytes and agranulocytes. The granulocytes
receive their name from the distinctive granules that are present in the cytoplasm of neutrophils, basophils, and
eosinophils. However, each of these cells also contains a multilobed nucleus, which accounts for their also being called
polymorphonuclear leukocytes. In laboratory terminology, they are often called “polys” or PMNs. The nongranulocytes,
which consist of the lymphocytes and monocytes, do not contain distinctive granules and have nonlobular nuclei that are
not necessarily spherical. The term mononuclear leukocytes is applied to these cells.
The endocrine system is an important regulator of the number of leukocytes in the blood. Hormones affect the production
of leukocytes in the blood-forming organs, their storage and release from the tissue, and their disintegration. A local
inflammatory process exerts a definite chemical effect on the mobilization of leukocytes. The life span of leukocytes
varies from 13 to 20 days, after which the cells are destroyed in the lymphatic system; many are excreted from the body
in fecal matter.
Leukocytes fight infection and defend the body by a process called phagocytosis, in which the leukocytes actually
encapsulate foreign organisms and destroy them. Leukocytes also produce, transport, and distribute antibodies as part of

the immune response to a foreign substance (antigen).
The WBC serves as a useful guide to the severity of the disease process. Specific patterns of leukocyte response can be
expected in various types of diseases as determined by the differential count (percentages of the different types of
leukocytes). Leukocyte and differential counts, by themselves, are of little value as aids to diagnosis unless the results
are related to the clinical condition of the patient; only then is a correct and useful interpretation possible.
Reference Values
Normal Black adults: 3.2–10.0 × 10 3/cells/mm 3 or × 10 9/L or 3200–10,000 cells/mm 3 Adults: 4.5–10.5 × 10 3/cells/mm
3
or × 10 9/L or 4500–10,500 cells/mm 3 Children: 0–2 weeks: 9.0–30.0 × 10 3/cells/mm 3 or × 10 9/L or 9000–30,000
cells/mm 3 2–8 weeks: 5.0–21.0 × 10 3/cells/mm 3 or × 10 9/L or 5000–21,000 cells/mm 3 2 months–6 years: 5.0–19.0 ×
10 3/cells/mm 3 or × 10 9 /L or 5000–19,000 cells/mm 3 6–18 years: 4.8–10.8 × 10 3/cells/mm 3 or × 10 9/L or
4800–10,800 cells/mm 3

NOTE
Different labs have slightly different reference values.
Procedure
1. Obtain a venous anticoagulated EDTA blood sample of 5 mL or a finger-stick sample. Place a specimen in a
biohazard bag.
2. Record the time when specimen was obtained (eg, 7:00 a.m.).
3. Blood is processed either manually or automatically, using an electronic counting instrument such as the Coulter
counter or Abbott Cell-Dyne.
Clinical Implications
1. Leukocytosis: WBC >11,000/mm 3 or >11.0 × 10 3/mm 3 (or >11 × 10 9/L)
a. It is usually caused by an increase of only one type of leukocyte, and it is given the name of the type of cell that
shows the main increase:
1. Neutrophilic leukocytosis or neutrophilia
2. Lymphocytic leukocytosis or lymphocytosis
3. Monocytic leukocytosis or monocytosis
4. Basophilic leukocytosis or basophilia
5. Eosinophilic leukocytosis or eosinophilia
b. An increase in circulating leukocytes is rarely caused by a proportional increase in leukocytes of all types.
When this does occur, it is usually a result of hemoconcentration.
c. In certain diseases (eg, measles, pertussis, sepsis), the increase of leukocytes is so great that the blood picture
suggests leukemia. Leukocytosis of a temporary nature (leukemoid reaction) must be distinguished from
leukemia. In leukemia, the leukocytosis is permanent and progressive.
d. Leukocytosis occurs in acute infections, in which the degree of increase of leukocytes depends on severity of
the infection, patient's resistance, patient's age, and marrow efficiency and reserve.
e. Other causes of leukocytosis include the following:
1. Leukemia, myeloproliferative disorders
2. Trauma or tissue injury (eg, surgery)
3. Malignant neoplasms, especially bronchogenic carcinoma
4. Toxins, uremia, coma, eclampsia, thyroid storm
5. Drugs, especially ether, chloroform, quinine, epinephrine (Adrenalin), colony-stimulating factors
6. Acute hemolysis
7. Hemorrhage (acute)
8. After splenectomy
9. Polycythemia vera
10. Tissue necrosis
f. Occasionally, leukocytosis is found when there is no evidence of clinical disease. Such findings suggest the
presence of:
1. Sunlight, ultraviolet irradiation
2. Physiologic leukocytosis resulting from excitement, stress, exercise, pain, cold or heat, anesthesia
3. Nausea, vomiting, seizures
g. Steroid therapy modifies the leukocyte response.
1. When corticotropin (adrenocorticotropic hormone, or ACTH) is given to a healthy person, leukocytosis
occurs.
2. When ACTH is given to a patient with severe infection, the infection can spread rapidly without producing the
expected leukocytosis; therefore, what would normally be an important sign is obscured.
2. Leukopenia: WBC <4000/mm 3 or <4.0 × 10 3/mm 3 or <4.0 cells × 10 9/L occurs during and following:
a. Viral infections, some bacterial infections, overwhelming bacterial infections
b. Hypersplenism
c. Bone marrow depression caused by heavy-metal intoxication, ionizing radiation, drugs:
1. Antimetabolites
2. Barbiturates
3. Benzene
4. Antibiotics
5. Antihistamines
6. Anticonvulsives
7. Antithyroid drugs

8. Arsenicals
9. Cancer chemotherapy (causes a decrease in leukocytes; leukocyte count is used as a link to disease)
10. Cardiovascular drugs
11. Diuretics
12. Analgesics and antiinflammatory drugs
d. Primary bone marrow disorders:
1. Leukemia (aleukemic)
2. Pernicious anemia
3. Aplastic anemia
4. Myelodysplastic syndromes
5. Congenital disorders
6. Kostmann's syndrome
7. Reticular agenesis
8. Cartilage-hair hypoplasia
9. Shwachman-Diamond syndrome
10. Chédiak-Higashi syndrome
e. Immune-associated neutropenia
f. Marrow-occupying diseases (fungal infection, metastatic tumor)
g. Pernicious anemia

Clinical Alert
1. WBC <500/mm 3 or <0.5 × 10 3 /mm 3 (or × 10 9/L) represents a panic value.
2. WBC >30,000/mm 3 or >30.0 × 10 3 (or × 10 9/L) is a panic value.
Interfering Factors
1. Hourly rhythm: there is an early-morning low level and late-afternoon high peak.
2. Age: in newborns and infants, the count is high (10,000/mm 3 to 20,000/mm 3 or 10 × 10 9/L to 20 × 10 9/L); the
count gradually decreases in children until the adult values are reached between 18 and 21 years of age.
3. Any stressful situation that leads to an increase in endogenous epinephrine production and a rapid rise in the
leukocyte count
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Refer to standard pretest care for hemogram, CBC, and differential count on page 47. Also, see Chapter 1
guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome and monitor appropriately. Refer to standard posttest care for hemogram, CBC, and
differential count on page 47. Also, follow Chapter 1 guidelines for safe, effective, informed posttest care .
2. In prolonged severe granulocytopenia or pancytopenia, give no fresh fruits or vegetables because the kitchen,
especially in a hospital, may be a source of food contamination. When the WBC is low, a person can get a
bacterial, pseudomonal, or fungal infection from fresh fruits and vegetables. Use a minimal-bacteria or commercially
sterile diet. All food must be served from a new or single-serving package. Consider a leukemia diet. See dietary
department for restrictions (eg, cooked food only) and careful food preparation. Do not give intramuscular
injections. Do not take rectal temperature, give suppositories, or give enemas. Do not use razor blades. Do not give
aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs), which cause abnormal platelet dysfunction. Watch
carefully for signs or symptoms of infection. Without leukocytes to produce inflammation, serious infections can
have very subtle findings. Often, patients have only a fever.
Differential White Blood Cell Count (Diff; Differential Leukocyte Count)
The total count of circulating white blood cells is differentiated according to the five types of leukocytes, each of which
performs a specific function.

Function of Circulating WBCs According to Leukocyte Type
Cell
These Cells Function to Combat
Neutrophils Pyogenic infections (bacterial)
Eosinophils Allergic disorders and parasitic infestations
Basophils
Parasitic infections, some allergic disorders
Lymphocytes Viral infections (measles, rubella, chickenpox, infectious mononucleosis)
Monocytes Severe infections, by phagocytosis

Differential for Leukocyte Count
Age
Bands/Stab (%)
Segs/Polys (%)

Eos (%)

Basos (%)

Lymphs (%)

Monos (%)

Metas (%)

Birth–1 wk 10–18
32–62
0–2
0–1
26–36
0–6
—
1–2 wk
8–16
19–49
0–4
0–0
38–46
0–9
—
2–4 wk
7–15
14–34
0–3
0–0
43–53
0–9
—
4–8 wk
7–13
15–35
0–3
0–1
41–71
0–7
—
2–6 mo
5–11
15–35
0–3
0–1
42–72
0–6
—
6 mo–1 y
6–12
13–33
0–3
0–0
46–76
0–5
—
1–6 y
5–11
13–33
0–3
0–0
46–76
0–5
—
6–16 y
5–11
32–54
0–3
0–1
27–57
0–5
—
16–18 y
5–11
34–64
0–3
0–1
25–45
0–5
—
>18 y
3–6
50–62
0–3
0–1
25–40
3–7
0–1
Bands or stab cells, immature forms of neutrophils; Segs, segmented neutrophils; Polys, polymorphonuclear neutrophils;
Eos, eosinophils; Basos, basophils; Lymphs, lymphocytes; Monos, monocytes; Metas, metamyelocytes.

The differential count is expressed as a percentage of the total number of leukocytes (WBC). The distribution (number
and type) of cells and the degree of increase or decrease are diagnostically significant. The percentages indicate the
relative number of each type of leukocyte in the blood. The absolute count of each type of leukocyte is obtained
mathematically by multiplying its relative percentage by the total leukocyte count. The formula is:

NOTE
This is now the preferred way of reporting.
The differential count alone has limited value; it must always be interpreted in relation to the WBC. If the percentage of
one type of cell is increased, it can be inferred that cells of that type are relatively more numerous than normal, but it is
not known whether this reflects an actual increase in the (absolute) number of cells that are relatively increased or an
absolute decrease in cells of another type. On the other hand, if the relative (percentage) values of the differential count
and the total WBC are both known, it is possible to calculate absolute values that are not subject to misinterpretation.
Historically, the differential count has been done manually, but the newer hematology instruments can now do an
automated differential count. The count is based on different chemical components of each cell type. However, not all
samples can be evaluated by automated methods. When a leukocyte count is extremely low or high, a manual count may
have to be done. Extremely abnormal leukocytes, such as those in leukemia, also have to be counted by hand. The
automated instrument has built-in quality control that senses abnormal cells and flags the differential. A microscopic
count must then be done.
Segmented Neutrophils (Polymorphonuclear Neutrophils, PMNs, Segs, Polys)
Neutrophils, the most numerous and important type of leukocytes in the body's reaction to inflammation, constitute a
primary defense against microbial invasion through the process of phagocytosis. These cells can also cause some body
tissue damage by their release of enzymes and endogenous pyogenes. In their immature stage of development,
neutrophils are referred to as “stab” or “band” cells. The term band stems from the appearance of the nucleus, which has
not yet assumed the lobed shape of the mature cell.
This test determines the presence of neutrophilia or neutropenia. Neutrophilia is an increase in the absolute number of
neutrophils in response to invading organisms and tumor cells. Neutropenia occurs when too few neutrophils are
produced in the marrow, too many are stored in the blood vessel margin, or too many have been called to action and
used up.
Reference Values
Normal Absolute count: 3000–7000/mm 3 or 3–7 × 10 9/L

NOTE
All references are using this SI unit for reporting.
Black adults: 1.2–6.6 × 10 9/L Differential: 50% of total WBC 0%–3% of total PMNs are stab or band cells
Procedure
1. Obtain a 5-mL blood sample in EDTA coagulant and place it in biohazard bag.
2. Count as part of the differential.
Clinical Implications
1. Neutrophilia (increased absolute number and relative percentage of neutrophils) >8.0 × 10 9 /L or 8000/mm 3; for
African Americans: >7.0 × 10 9/L or 7000/mm 3
a. Acute, localized, and general bacterial infections. Also, fungal and spirochetal and some parasitic and rickettsial
infections.
b. Inflammation (eg, vasculitis, rheumatoid arthritis, pancreatitis, gout), and tissue necrosis (myocardial infarction,
burns, tumors).

c. Metabolic intoxications (eg, diabetes mellitus, uremia, hepatic necrosis)
d. Chemicals and drugs causing tissue destruction (eg, lead, mercury, digitalis, venoms)
e. Acute hemorrhage, hemolytic anemia, hemolytic transfusion reaction
f. Myeloproliferative disease (eg, myeloid leukemia, polycythemia vera, myelofibrosis)
g. Malignant neoplasms—carcinoma
h. Some viral infections (noted in early stages) and some parasitic infections
2. Ratio of segmented neutrophils to band neutrophils: normally 1%–3% of PMNs are band forms (immature
neutrophils).
a. Degenerative shift to left: in some overwhelming infections, there is an increase in band (immature) forms with
no leukocytosis (poor prognosis).
b. Regenerative shift to left: there is an increase in band (immature) forms with leukocytosis (good prognosis) in
bacterial infections.
c. Shift to the right: decreased band (immature) cells with increased segmented neutrophils can occur in liver
disease, megaloblastic anemia, hemolysis, drugs, cancer, and allergies.
d. Hypersegmentation of neutrophils with no band (immature) cells is found in megaloblastic anemias (eg,
pernicious anemia) and chronic morphine addiction.
3. Neutropenia (decreased neutrophils)
a. <1800/mm 3 or <1.8 × 10 9 /L
b. African Americans: <1000/mm 3 or <40% of differential count
c. Causes associated with decreased or ineffective production:
1. Inherited stem cell disorders and genetic disorders or cellular development
2. Acute overwhelming bacterial infections (poor prognosis) and septicemia
3. Viral infections (eg, mononucleosis, hepatitis, influenza, measles)
4. Some rickettsial and parasitical (protozoan) diseases (malaria)
5. Drugs, chemicals, ionizing radiation, venoms
6. Hematopoietic diseases (eg, aplastic anemia, megaloblastic anemias, iron-deficiency anemia, aleukemic
leukemia, myeloproliferative diseases)
d. Causes associated with decreased survival:
1. Infections mainly in persons with little or no marrow reserves, elderly people, and infants
2. Collagen vascular diseases with antineutrophil antibodies (eg, systemic lupus erythematosus [SLE] and
Felty's syndrome)
3. Autoimmune and isoimmune causes
4. Drug hypersensitivity (There is an extensive list of drugs that continues to grow. Women are more likely than
men to have a drug sensitivity. Removal of offending drug results in return to normal.)
5. Splenic sequestration
e. Neutropenia in neonates (<5000/mm 3 or <5.0 × 10 9 /L or <1000/mm 3 or <1.0 × 10 9/L after first week of life)
1. Maternal neutropenia, maternal drug ingestion, maternal isoimmunization to fetal leukocytes (maternal
immunoglobulin G [IgG] antibodies to fetal neutrophils)
2. Inborn errors of metabolism (eg, maple syrup urine disease)
3. Immune deficits—acquired
4. Deficits and disorders of myeloid stem cell (eg, Kostmann's agranulocytosis, benign chronic
granulocytopenia of childhood)
5. Congenital neutropenia
f. Pregnancy—progressive decrease until labor
4. Other leukocyte abnormalities and corresponding diseases are listed in Table 2.2.
Table 2.2 Leukocyte Abnormalities and Diseases
Abnormality

Description

Associated Diseases

Toxic granulation

Coarse, black or purple, cytoplasmic
granules
Small (1–2 µm), blue, cytoplasmic
inclusions in neutrophils
Neutrophil with bilobed nucleus or
no segmentation of nucleus;
chromatin is coarse, and cytoplasm
is pink with normal granulation
Basophilic, cytoplasmic inclusions of
leukocytes; similar to Döhle bodies
Prominent azurophilic granulation in
leukocytes; similar to toxic
granulation; granulation is seen
better with Giemsa stain
Gray-green, large cytoplasmic
inclusions that are fused giant
lysomes (phospholipids)
Neutrophilic leukocyte with a
homogenous red-purple inclusion
that distends the cell's cytoplasm

Infections or inflammatory diseases; acute reactive
state
Infections or inflammatory diseases, burns

Döhle bodies
Pelger-Huët
anomalies

May-Hegglin anomaly
Alder-Reilly anomaly

Chédiak-Higashi
anomaly
LE (lupus
erythematosus) cells

Tart cell

Neutrophilic leukocyte with a
phagocytized nucleus of a
granulocyte that retains some
nuclear structure

Hereditary (congenital), myelogenous leukemia

May-Hegglin syndrome (hereditary), includes
thrombocytopenia and giant platelets
Hereditary, mucopolysaccharidosis

Chédiak-Higashi syndrome; few cases of acute
myeloid leukemia
Lupus erythematosus and other collagen diseases,
chronic hepatitis, drug reactions, serum sickness
(not naturally occurring in the body—must be
induced to form by mechanical trauma in vitro)
Drug reactions (eg, penicillin, procainamide) or
actual phagocytosis

Myeloid “shift to left”

Presence of bands, myelocytes,
metamyelocytes, or promyelocytes

Hypersegmented
neutrophil

Mature neutrophil with more than
five distinct lobes

Leukemic cells (eg,
lymphoblasts,
myeloblasts)

Presence of lymphoblasts,
myeloblasts, monoblasts,
myelomonoblasts, promyelocytes
(none normally present in peripheral
blood)
Rod-like, 1–6 µm long, red-purple,
refractile inclusions in neutrophils
Disintegrating nucleus of a ruptured
leukocyte

Auer bodies
Smudge cell

Infections, intoxications, tissue necrosis,
myeloproliferative syndrome, leukemia (chronic
myelocytic), leukemoid reaction, pernicious
anemia, hyposplenism
Megaloblastic anemia, hereditary constitutional
hypersegmentation of neutrophils; long-term
chronic infection
Leukemia (acute or chronic), leukemoid reaction,
severe infectious or inflammatory diseases,
myeloproliferative syndrome, intoxications,
malignancies, recovery from bone marrow
suppression
Acute myelocytic leukemia or myelomonocytic
leukemia
Increased numbers in leukemic blood, particularly
in acute lymphocytic leukemia or chronic
lymphocytic leukemia when WBC count is greater
than 10,000/mm 3 or >10 × 10 9/L

NOTE
An ethnic difference exists only in neutrophils.
Interfering Factors
1. Physiologic conditions such as stress, excitement, fear, vomiting, electric shock, anger, joy, and exercise
temporarily cause increased neutrophils. Crying babies have neutrophilia.
2. Obstetric labor and delivery cause neutrophilia. Menstruation causes neutrophilia.
3. Steroid administration: neutrophilia peaks in 4 to 6 hours and returns to normal by 24 hours (in severe infection,
expected neutrophilia does not occur).
4. Exposure to extreme heat or cold.
5. Age
a. Children respond to infection with a greater degree of neutrophilic leukocytosis than adults do.
b. Some elderly patients respond weakly or not at all, even when infection is severe.
6. Resistance
a. People of any age who are weak and debilitated may fail to respond with a significant neutrophilia.
b. When an infection becomes overwhelming, the patient's resistance is exhausted and, as death approaches, the
number of neutrophils decreases greatly.
7. Myelosuppressive chemotherapy
8. Many drugs cause increases or decreases in neutrophils.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Refer to standard pretest care for hemogram, CBC, and differential count on page 47. Also, see Chapter 1
guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately for neutrophilia or neutropenia.
2. Refer to standard posttest care for hemogram, CBC, and differential count on page 47. Also, follow Chapter 1
guidelines for safe, effective, informed posttest care.

Clinical Alert
Agranulocytosis (marked neutropenia and leukopenia) is extremely dangerous and is often fatal because the body is
unprotected against invading agents. Patients with agranulocytosis must be protected from infection by means of
reverse isolation techniques with strictest emphasis on handwashing technique.
Eosinophils
Eosinophils, capable of phagocytosis, ingest antigen-antibody complexes and become active in the later stages of
inflammation. Eosinophils respond to allergic and parasitic diseases. Eosinophilic granules contain histamine (one third
of all the histamine in the body).
This test is used to diagnose allergic infections, assess severity of infestations with worms and other large parasites, and
monitor response to treatment.
Reference Values
Normal Absolute count: 0–0.7 × 10 9 /L Differential: 0%–3% of total WBC

Procedure
1.
2.
3.
4.

Obtain a 5-mL blood sample in EDTA anticoagulant. Place it in a biohazard bag.
Note the time the blood sample is obtained (eg, 3:00 p.m.).
Perform a total WBC, make a blood smear, count 100 cells, and report the percentage of eosinophils.
Be aware that an absolute eosinophil count is also available. It is done with a special eosinophil stain and manual
counting on a hemacytometer. It must be done within 4 hours after collection or, if refrigerated, within 24 hours.

Clinical Implications
1. Eosinophilia (increased circulating eosinophils) >5% or >500 cells/mm 3 or >0.5 × 10 9/L occurs in:
a. Allergies, hay fever, asthma
b. Parasitic disease and trichinosis tapeworm, especially with tissue invasion
c. Some endocrine disorders, Addison's disease, hypopituitarism
d. Hodgkin's disease and myeloproliferative disorders, chronic myeloid leukemia, polycythemia vera
e. Chronic skin diseases (eg, pemphigus, eczema, dermatitis herpetiformis)
f. Systemic eosinophilia associated with pulmonary infiltrates (PIE)
g. Some infections (scarlet fever, chorea), convalescent stage of other infections
h. Familial eosinophilia (rare), hypereosinophilic syndrome (HES)
i. Polyarteritis nodosa, collagen vascular diseases (eg, SLE), connective tissue disorders
j. Eosinophilic gastrointestinal diseases (eg, ulcerative colitis, Crohn's disease)
k. Immunodeficiency disorders (Wiskott-Aldrich syndrome, immunoglobulin A deficiency)
l. Aspirin sensitivity, allergic drug reactions
m. Löffler's syndrome (related to Ascaris species infestation), tropical eosinophilia (related to filariasis)
n. Poisons (eg, black widow spider, phosphorus)
o. Hypereosinophilic syndrome (>1.5 × 10 9/L), persistent extreme eosinophilia with eosinophilic infiltration of
tissues causing tissue damage and organ dysfunction
1. Eosinophilic leukemia
2. Trichinosis invasion
3. Dermatitis herpetiformis
4. Idiopathic
2. Eosinopenia (decreased circulating eosinophils) is usually caused by an increased adrenal steroid production that
accompanies most conditions of bodily stress and is associated with:
a. Cushing's syndrome (acute adrenal failure): <50/mm 3
b. Use of certain drugs such as ACTH, epinephrine, thyroxine, prostaglandins
c. Acute bacterial infections with a marked shift to the left (increase in immature leukocytes)
3. Eosinophilic myelocytes are counted separately because they have a greater significance, being found only in
leukemia or leukemoid blood pictures.
Interfering Factors
1. Daily rhythm: normal eosinophil count is lowest in the morning, then rises from noon until after midnight. For this
reason, serial eosinophil counts should be repeated at the same time each day.
2. Stressful situations, such as burns, postoperative states, electroshock, and labor, cause a decreased count.
3. After administration of corticosteroids, eosinophils disappear.
4. See Appendix J for drugs that affect test outcomes.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Refer to standard patient care for hemogram, CBC, and differential count on page 47. Also, see Chapter 1
guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately.
2. Use special precautions if patient is receiving steroid therapy, epinephrine, thyroxine, or prostaglandins.
Eosinophilia can be masked by steroid use.
3. Refer to standard posttest care for hemogram, CBC, and differential count on page 47. Also, follow Chapter 1
guidelines for safe, effective, informed posttest care.
Basophils
Basophils, which constitute a small percentage of the total leukocyte count, are considered phagocytic. The basophilic
granules contain heparin, histamines, and serotonin. Tissue basophils are called mast cells and are similar to blood
basophils. Normally, mast cells are not found in peripheral blood and are rarely seen in healthy bone marrow.
Basophil counts are used to study chronic inflammation. There is a positive correlation between high basophil counts and
high concentrations of blood histamines, although this correlation does not imply cause and effect. It is extremely difficult
to diagnose basopenia because a 1000–10,000 count differential would have to be done to get an absolute count.
Reference Values
Normal Absolute count: 15–50/mm 3 or 0.02–0.05 × 10 9/L Differential: 0%–1.0% of total WBC

Procedure
1. Obtain a 5-mL blood sample in EDTA and count as part of the differential.
2. Place the sample in a biohazard bag.
Clinical Implications
1. Basophilia (increased count) >50/mm 3 or >0.05 × 10 9/L is commonly associated with the following:
a. Granulocytic (myelocytic) leukemia
b. Acute basophilic leukemia
c. Myeloid metaplasia, myeloproliferative disorders
d. Hodgkin's disease
2. It is less commonly associated with the following:
a. Inflammation, allergy, or sinusitis
b. Polycythemia vera
c. Chronic hemolytic anemia
d. After splenectomy
e. After ionizing radiation
f. Hypothyroidism
g. Infections, including tuberculosis, smallpox, chickenpox, influenza
h. Foreign protein injection
3. Basopenia (decreased count) <20/mm 3 or <0.02 × 10 9/L is associated with the following:
a. Acute phase of infection
b. Hyperthyroidism
c. Stress reactions (eg, pregnancy, myocardial infarction)
d. After prolonged steroid therapy, chemotherapy, radiation
e. Hereditary absence of basophils
f. Acute rheumatic fever in children
4. Presence of numbers of tissue mast cells (tissue basophils) is associated with:
a. Rheumatoid arthritis
b. Urticaria, asthma
c. Anaphylactic shock
d. Hypoadrenalism
e. Lymphoma
f. Macroglobulinemia
g. Mast cell leukemia
h. Lymphoma invading bone marrow
i. Urticaria pigmentosa
j. Asthma
k. Chronic liver or renal disease
l. Osteoporosis
m. Systemic mastocytosis
Interfering Factors See Appendix J for drugs that affect test outcomes.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure
2. Refer to standard patient care for hemogram, CBC, and differential count on page 47. Also, see Chapter 1
guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately.
2. Use special precautions if patient is receiving steroid therapy, epinephrine, thyroxine, or prostaglandins.
Eosinophilia can be masked by steroid use.
3. Refer to standard posttest care for hemogram, CBC, and differential count on page 47. Also, follow Chapter 1
guidelines for safe, effective, informed posttest care.
Monocytes (Monomorphonuclear Monocytes)
These agranulocytes, the largest cells of normal blood, are the body's second line of defense against infection.
Histiocytes, which are large macrophagic phagocytes, are classified as monocytes in a differential leukocyte count.
Histiocytes and monocytes are capable of reversible transformation from one to the other.
These phagocytic cells of varying size and mobility remove injured and dead cells, microorganisms, and insoluble
particles from the circulating blood. Monocytes escaping from the upper and lower respiratory tracts and the
gastrointestinal and genitourinary organs perform a scavenger function, clearing the body of debris. These phagocytic
cells produce the antiviral agent called interferon.
This test counts monocytes, which circulate in certain specific conditions such as tuberculosis, subacute bacterial
endocarditis, and the recovery phase of acute infections.
Reference Values

Normal Absolute count: 100–500/mm 3 or 0.1–0.5 × 10 9/L Differential: 3%–7% of total WBC or 0.03–0.07 of total WBC
Procedure
1. Obtain a 5-mL blood sample in EDTA and count as part of the differential.
2. Observe standard precautions.
Clinical Implications
1. In monocytosis: a monocyte increase of >500 cells/mm 3 or >0.5 × 10 9 /L or >10%. The most common causes are
bacterial infections, tuberculosis, subacute bacterial endocarditis, and syphilis.
2. Other causes of monocytosis:
a. Monocytic leukemia and myeloproliferative disorders
b. Carcinoma of stomach, breast, or ovary
c. Hodgkin's disease and other lymphomas
d. Recovery state of neutropenia (favorable sign)
e. Lipid storage diseases (eg, Gaucher's disease)
f. Some parasitic mycotic and rickettsial diseases
g. Surgical trauma
h. Chronic ulcerative colitis, enteritis, and sprue
i. Collagen diseases and sarcoidosis
j. Tetrachlorethane poisoning
3. Phagocytic monocytes (macrophages) may be found in small numbers in the blood in many conditions:
a. Severe infections (sepsis)
b. Lupus erythematosus
c. Hemolytic anemias
4. Decreased monocyte count (<100 cells/mm 3 or <0.1 × 10 9 /L) is not usually identified with specific diseases:
a. Prednisone treatment
b. Hairy cell leukemia
c. Overwhelming infection that also causes neutropenia
d. Human immunodeficiency virus (HIV) infection
e. Aplastic anemia (bone marrow injury)
Interfering Factors See Appendix J for drugs that affect test outcomes.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Refer to standard pretest care for hemogram, CBC, and differential count on page 47. Also, see Chapter 1
guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately for leukemia and infection.
2. Refer to standard posttest care for hemogram, CBC, and differential count on page 47. Also, follow Chapter 1
guidelines for safe, effective, informed posttest care.
Lymphocytes (Monomorphonuclear Lymphocytes); CD4, CD8 Count; Plasma Cells
Lymphocytes are small, mononuclear cells without specific granules. These agranulocytes are motile cells that migrate to
areas of inflammation in both early and late stages of the process. These cells are the source of serum immunoglobulins
and of cellular immune response and play an important role in immunologic reactions. All lymphocytes are manufactured
in the bone marrow. B lymphocytes mature in the bone marrow, and T lymphocytes mature in the thymus gland. B cells
control the antigen-antibody response that is specific to the offending antigen and is said to have “memory.” The T cells,
the master immune cells, include CD4 + helper T cells, killer cells, cytotoxic cells, and CD8 + suppressor T cells.
Plasma cells (fully differentiated B cells) are similar in appearance to lymphocytes. They have abundant blue cytoplasm
and an eccentric, round nucleus. Plasma cells are not normally present in blood.
This test measures the number of lymphocytes in the peripheral blood. Lymphocytosis is present in various diseases and
is especially prominent in viral disorders. Lymphocytes and their derivatives, the plasma cells, operate in the immune
defenses of the body.
Reference Values
Normal Lymphocytes: 25%–40% of total leukocyte count (relative value) or 1500–4000 cells/mm 3 or 1.5–4.0 × 10 9 /L
Plasma cells: 0% or none CD4 count: total WBC × lymphocytes (%) × lymphocytes (%) stained with CD4 CD4/CD8 ratio:
>1.0
Procedure
1. Obtain 5 mL of EDTA-anticoagulated blood. Place the specimen in a biohazard bag.
2. Count lymphocytes as part of the differential count.
Clinical Implications

1. Lymphocytosis: >4000/mm 3 or >4.0 × 10 9/L in adults; >7200/mm 3 or >7.2 × 10 9 in children; and >9000/mm 3 or
>9.0 × 10 9 /L in infants occurs in:
a. Lymphatic leukemia (acute and chronic) lymphoma
b. Infectious lymphocytosis (occurs mainly in children)
c. Infectious mononucleosis:
1. Caused by Epstein-Barr virus
2. Most common in adolescents and young adults
3. Characterized by atypical lymphocytes (Downey cells) that are large, deeply indented, with deep blue
(basophilic) cytoplasm
4. Differential diagnosis—positive heterophil test
d. Other viral diseases:
1. Viral infections of the upper respiratory tract (pneumonia)
2. Cytomegalovirus
3. Measles, mumps, chickenpox
4. Acute HIV infection
5. Infectious hepatitis (acute viral hepatitis)
6. Toxoplasmosis
e. Some bacterial diseases such as tuberculosis, brucellosis (undulant fever), and pertussis
f. Crohn's disease, ulcerative colitis (rare)
g. Serum sickness, drug hypersensitivity
h. Hypoadrenalism, Addison's disease
i. Thyrotoxicosis (relative lymphocytosis)
j. Neutropenia with relative lymphocytosis
2. Lymphopenia: <1000 cells/mm 3 or <1.0 × 10 9/L in adults; <2500 cells/mm 3 or <2.5 × 10 9 /L in children occurs in:
a. Chemotherapy, radiation treatment (immunosuppressive medications)
b. After administration of ACTH or cortisone (steroids); with ACTH-producing pituitary tumors
c. Increased loss via gastrointestinal tract owing to obstruction of lymphatic drainage (eg, tumor, Whipple's
disease, intestinal lymphectasia)
d. Aplastic anemia
e. Hodgkin's disease and other malignancies
f. Inherited immune disorders, acquired immunodeficiency syndrome (AIDS), and AIDS-immune dysfunction
g. Advanced tuberculosis (“miliary” tuberculosis), renal failure, SLE
h. Severe debilitating illness of any king
i. Congestive heart failure
3. CD4 count: the number of CD4 + lymphocytes is equal to the absolute number of lymphocytes (total WBC ×
differential [%] of lymphocytes) times the percentage of lymphocytes staining positively for CD4. A severely
depressed CD4 count is the single best indicator of imminent opportunistic infection.
a. Decreased CD4 lymphocytes
1. Immune dysfunction, especially AIDS
2. Acute minor viral infections
b. Increased CD4 lymphocytes
1. Therapeutic effect of drugs
2. Diurnal variation: peak evening values may be two times morning values.
4. Plasma cells (not normally present in blood) are increased in:
a. Plasma cell leukemia
b. Multiple myeloma
c. Hodgkin's disease
d. Chronic lymphatic leukemia
e. Cancer of liver, breast, prostate
f. Cirrhosis
g. Rheumatoid arthritis, SLE
h. Serum reaction
i. Some bacterial, viral, and parasitic infections
Interfering Factors
1. Physiologic pediatric lymphocytosis is a condition in newborns that includes an elevated WBC and
abnormal-appearing lymphocytes that can be mistaken for malignant cells.
2. Exercise, emotional stress, and menstruation can cause an increase in lymphocytes.
3. African Americans normally have a relative (not absolute) increase in lymphocytes.
4. See Appendix J for drugs that affect outcomes.

Abnormal Lymphocytes
Abnormality
Description
Atypical
Lymphocytes, some with vacuolated cytoplasm, irregularly
lymphocytes shaped nucleus, increased numbers of cytoplasmic azurophilic
Reactive
granules, and peripheral basophilia; or some with more
lymphocytes abundant basophilic cytoplasm, grossly indented cytoplasm
Downey cells
Turk cells

Associated Diseases
Infectious mononucleosis, viral hepatitis,
other viral infections, tuberculosis, drug
(eg, penicillin) sensitivity, posttransfusion
syndrome

Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Refer to standard pretest care for hemogram, CBC, and differential count on page 47. Also, see Chapter 1
guidelines for safe, effective, informed pretest care.

Clinical Alert
A decreased lymphocyte count <500/mm 3 (<0.5 × 10 9 /L) means that a patient is dangerously susceptible to infection,
especially viral infections. Institute measures to protect patient from infection.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately for lymphocytosis or lymphopenia.
2. Refer to standard posttest care for hemogram, CBC, and differential count on page 47. Also, follow Chapter 1
guidelines for safe, effective, informed posttest care.
Lymphocyte Immunophenotyping (T and B Cells)
Lymphocytes are divided into two categories, T and B cells, according to their primary function within the immune system.
In the body, T and B cells work together to help provide protection against infections, oncogenic agents, and foreign
tissue, and they play a vital role in regulating self-destruction or autoimmunity.
Most circulating lymphocytes are T cells with a life span of months to years. The life span of B cells is measured in days.
B cells (antibody) are considered “bursa or bone marrow dependent” and are responsible for humoral immunity (in which
antibodies are present in the serum). T cells (cellular) are thymus derived and are responsible for cellular immunity. T
cells are further divided into helper T (CD3 +, CD4 +) cells and suppressor T (CD3 +, CD8 +) cells.
Evaluation of lymphocytes in the clinical laboratory is performed by quantitation of the lymphocytes and their
subpopulations and by assessment of their function activity. These laboratory analyses have become an essential
component of the clinical assessment of two major disease states: lymphoproliferative states (eg, leukemia, lymphoma),
in which characterization of the malignant cell in terms of lineage and stage of differentiation provides valuable
information to the oncologist to guide prognosis and appropriate therapy; and immunodeficient states (eg, HIV infection,
organ transplantation), in which the alterations in the immune system that occur secondary to infection are evaluated.
The method of lymphocyte quantitation and characterization is based on the detection of cell surface markers by very
specific monoclonal antibodies. For cell surface immunophenotyping, flow cytometry has become the method of choice.
Cell surface phenotyping is accomplished by reacting cells from an appropriate specimen with one or more labeled
monoclonal antibodies and passing them through a flow cytometer, which counts the proportion of labeled cells.
Reference Values
Normal for Adult Peripheral Blood by Flow Cytometry T and B surface markers: Total T cells (CD3 +): 53%–88%
Helper T cells (CD3 +, CD4 +): 32%–61% Suppressor T cells (CD3 +, CD8 +): 18%–42% B cells (CD19 +): 5%–20%
Natural killer cells (CD16 +): 4%–32% Absolute counts (based on pathologist's interpretation): Total lymphocytes:
660–4600/mm 3 (0.6–4.6 × 10 9/L) Total T cells (CD3 +): 812–2318/mm 3 Helper T cells (CD3 +, CD4 +): 589–1505/mm 3
Suppressor T cells (CD3 +, CD8 +): 325–997/mm 3 B cells (CD19 +): 92–426/mm 3 Natural killer cells (CD16 +):
78–602/mm 3 Lymphocyte ratio: Helper-to-suppressor T-cell ratio >1.0
Procedure
1. Obtain a 5-mL EDTA-anticoagulated blood sample (lavender-topped tube).
2. Do not refrigerate or freeze the sample; it should remain at room temperature until testing is performed. Collect a
separate 5-mL venous EDTA-anticoagulated blood sample for hematology at the same time. Because the
interpretation of data is based on absolute values, it is imperative that a WBC and differential count also be
performed so that the appropriate data can be obtained.
Clinical Implications
1.
2.
3.
4.

Standard immunosuppressive drug therapy usually decreases lymphocyte totals.
Patients with an absolute helper T-lymphocyte count <200/mm 3 are at greatest risk for developing clinical AIDS.
Decreased T cells occur in congenital immunodeficiency diseases (eg, DiGeorge syndrome, thymic hypoplasia).
Decreased T cells occur in kidney and heart transplant patients receiving OKT-3, an immunomodulatory drug used
to prevent rejection.
5. A marked increase in B cells occurs in lymphoproliferative disorders (eg, chronic lymphocytic leukemia). In the
typical case of chronic lymphocytic leukemia, the B cells would be positive for either ? or ? light chains (indicating
monoclonality) and would express CD19 (a B-cell antigen).
Interventions
Pretest Patient Care
1. Explain purpose and specimen collection procedure. A recent viral cold can cause a decrease in total T cells, as
can medications such as corticosteroids. Nicotine and strenuous exercise have also been shown to decrease
lymphocyte counts.

2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and possible need for repeat testing. Lymphocyte immunophenotyping is performed to
monitor patients who are HIV positive and have begun medication treatment. Transplantation patients are also
retested at regular intervals to assess the threat of organ rejection or host infection. Also, see Chapter 8 for further
discussion of CD4 and CD8 cells.
2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

STAINS FOR LEUKEMIAS
Several special WBC staining methods are used to diagnose leukemia, amyloid disease, lymphoma, and
erythroleukemia; to differentiate erythema myelosis from sideroblastic anemia; to monitor progress and response to
therapy; and to detect early relapse. Amyloid refers to starchlike substances deposited in certain diseases (eg,
tuberculosis, osteomyelitis, leprosy, Hodgkin's disease, and carcinoma).
Sudan Black B (SBB) Stain
The SBB stain aids in differentiation of the immature cells of acute leukemias, especially acute myeloblastic leukemia.
The SBB stains a variety of fats and lipids that are present in myeloid leukemias but not present in the lymphoid
leukemias.
Reference Values
Positive Reactions Granulocytic cells (neutrophils and eosinophils) Myeloblasts Promyelocytes Neutrophilic myelocytes
Metamyelocytes, bands, and segmented neutrophils Eosinophils at all stages Monocytes and precursors
Variable Reactions Basophils
Negative Reactions (Sudanophobia) Lymphocytes and lymphocytic precursors Megakaryocytes and thrombocytes
(platelets) Erythrocytes Erythroblasts may display a few granules that represent mitochondrial phospholipid components
Procedure
1. Obtain bone marrow aspirate.
2. Prepare slide, stain with SBB, and scan microscopically. Use normal smear control.
Clinical Implications
1. Positive staining of primitive (blast) cells indicates myelogenous origin of cells. SBB is positive in acute myelocytic
leukemia (AML).
2. SBB is negative in acute lymphocytic leukemia, monocytic leukemia, plasma cell leukemia, and megakaryocyte
leukemia.
3. SBB is weak to negative in acute monocytic leukemia.
Interfering Factors There are cases of acute leukemia in which the cytochemical stains are not useful and fail to reveal
the differentiating features of any specific cell line.
Interventions
Pretest Patient Care
1. Explain test purposes and procedures. If bone marrow aspiration is done, see pages for special care.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes; counsel and monitor appropriately for leukemia, amyloid disease, anemia, and infection.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Periodic Acid–Schiff (PAS) Stain
The PAS stain aids in the diagnosis of acute lymphoblastic leukemia (ALL). Early myeloid precursors and erythrocyte
precursors are negative. As granulocytes mature, they increase in PAS positivity, whereas mature RBCs stay negative.
The PAS stain cannot be used to distinguish between AAL and AML or between benign and malignant lymphocytic
disorders.
Reference Values
Normal Lymphoblasts: stain (positive) Myeloblasts: do not stain (negative)
Procedure
1. Obtain bone marrow aspirate.
2. Prepare slide, stain with PAS, and scan microscopically.
Clinical Implications
1. Positive reaction
a. Blasts in ALL in childhood often have coarse clumps or masses of PAS-positive material within their scent
cytoplasm. The staining pattern is usually heterogeneous, with some cells containing PAS-positive clumps and

others virtually unstained.
b. Acute monocytic leukemia
c. Hairy cell leukemia
d. Sézary's syndrome
e. Conspicuous PAS positivity in the erythroid precursors is strongly suggestive of erythroleukemia (M 6 ).
2. Weakly positive
a. In acute granulocytic leukemia, the blasts display either a negative or weakly positive, finely granular pattern.
b. In some cases of thalassemia and in anemias with blocked or deficient iron, the red blood cell precursors also
contain PAS-positive material.
c. Hodgkin's disease, now Hodgkin's lymphoma
d. Infectious mononucleosis
3. Negative stain
a. Lymphoblasts of Burkitt's lymphoma
b. Megaloblastic leukemia
Interventions
Pretest Patient Care
1. Explain test purposes and procedures.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes; counsel and monitor appropriately.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Terminal Deoxynucleotidyl Transferase (TDT) Stain
The thymus is the primary site of TDT-positive cells, and TDT is found in the nucleus of the more primitive T cells. A
thymus-related population of TDT-positive cells resides in the bone marrow (normally a minor population, 0%–2%). TDT
is increased in >90% of cases of ALL of childhood. A minor (5%–10%) population of patients with acute nonlymphoblastic
leukemia have TDT-positive blasts. TDT-positive blasts are prominent in some cases of chronic myelogenous leukemia
(CML), relating to the development of an acute blast phase. TDT has been reported to assist in establishing the
diagnosis of ALL. TDT-positive cases of blast-phase CML correlate with a positive response to chemotherapy (vincristine
and prednisone).
Reference Values
Normal Negative in nonlymphoblastic leukemia Negative in peripheral blood 0% to 2% positive in bone marrow
Procedure
1. Obtain a 5-mL EDTA-anticoagulated peripheral blood sample or a 2-mL EDTA-anticoagulated bone marrow
aspirate.
2. Dry slides (store at room temperature for up to 5 days), process, and stain, then examine under the microscope for
positive cells.
Clinical Implications
1. TDT is positive in ALL, lymphoblastic lymphoma, and CML (blast crisis).
2. TDT is negative in patients in remission and in those with CML or chronic lymphatic leukemia.
Interventions
Pretest Patient Care
1. Explain test purposes and procedures.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes; counsel and monitor appropriately.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Leukocyte Alkaline Phosphatase (LAP) Stain
Neutrophils are the only leukocytes to contain various amounts of alkaline phosphatase.
The LAP stain is used as an aid to distinguish chronic granulocytic leukemia from a leukemoid reaction. A leukemoid
reaction is a high WBC that may look like leukemia but is not. In remission of CML, the LAP may return to normal. In the
blast phase of CMC, the LAP may be elevated.
Reference Values
Normal 40–100 LAP units

NOTE
Each laboratory must establish its own normal values.
Procedure
1. Obtain specimen by capillary puncture, venous blood (EDTA), or bone marrow aspirate. Prepare smear and air-dry;
stain with LAP.
2. Make a count of 100 granulocytes and score (from 0 to 4+) as to the degree of LAP units.
Clinical Implications
1. Decreased values (0–15 LAP units):
a. CML
b. Paroxysmal nocturnal hemoglobinuria (PNH)
c. Idiopathic thrombocytopenic purpura
d. Hereditary hypophosphatasia
e. Progressive muscular dystrophy
f. Marked eosinophilia
g. Nephrotic syndrome
h. Siderocytic anemia
2. Increased values:
a. Leukemoid reactions, all kinds of neutrophilia with elevated WBC
b. Polycythemia vera
c. Thrombocytopenia (essential)
d. Down syndrome (trisomy 21)
e. Multiple myeloma
f. Hodgkin's disease
g. Hairy cell leukemia
h. Aplastic leukemia, acute and chronic lymphatic leukemia, chronic granulocytic leukemia
i. Myelofibrosis, myeloid metaplasia
3. Normal levels of LAP:
a. Secondary polycythemia
b. Hemolytic anemia
c. Infectious mononucleosis
d. Iron-deficiency anemia
e. Viral hepatitis
4. Serial LAP tests can be a useful adjunct in evaluating the activity of Hodgkin's disease and the response to therapy.
Interfering Factors
1. Any physiologic stress, such as third-trimester pregnancy, labor, or severe exercise, causes an increased LAP
score.
2. Steroid therapy increases LAP score.
3. CML with infection increases the LAP score.
Interventions
Pretest Patient Care
1. Explain test purposes and procedures.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes; counsel and monitor appropriately for blood diseases.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Tartrate-Resistant Acid Phosphatase (TRAP) Stain
The malignant mononuclear cells of leukemic reticuloendotheliosis (hairy cell leukemia) are resistant to inhibition by
tartaric acid. There is evidence that the reaction is not entirely specific because TRAP reactions have been reported in
prolymphocytic leukemia and malignant lymphoma and in some cases of infectious mononucleosis.
Reference Values
Normal No TRAP activity
Procedure
1. Obtain venous blood sample (5 mL) or bone marrow smear.
2. Incubate blood smear with TRAP, counterstain, and examine microscopically.
Clinical Implications
1. TRAP is present in the leukemic cells of most patients with hairy cell leukemia; 5% of patients with otherwise typical
hairy cell leukemia lack the enzyme.

2. TRAP occasionally occurs in malignant cells of patients with lymphoproliferative disorders other than hairy cell
leukemia.
3. Histiocytes have weakly positive reactions.
Interventions
Pretest Patient Care
1. Explain test purposes and procedures. Assess for history of signs and symptoms of leukemia.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes; counsel and monitor appropriately.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .

TESTS OF RED BLOOD CELLS
Many tests look at the red blood cells: their number and size, amount of Hb, rate of production, and percent composition
of the blood. The red blood cell count (RBC), hematocrit (Hct), and hemoglobin (Hb) are closely related but different ways
to look at the adequacy of erythrocyte production. The same conditions cause an increase (or decrease) in each of these
indicators.

Peripheral Red Blood Cell Abnormalities
Abnormality
Description
Anisocytosis (diameter)
Abnormal variation in size
(normal diameter = 6–8 µm)
Microcytes
Small cells, <6 µm (MCV <80 fL)
Macrocytes

Large cells, >8 µm (MCV >100
fL)

Megalocytes

Large (>9 µm) oval cells

Hypochromia

Pale cells with decreased
concentration of hemoglobin
(MCHC <30 g/dL)
Abnormal variation in shape

Poikilocytes

Spherocytes

Elliptocytes
Stomatocytosis
Sickle cells
Target cells

Schistocytes (helmet
cells)

Burr cells (echinocytes)
Acanthocytes

Teardrop cells,
(dacrocytes)
Nucleated red cells

Associated Diseases
Any severe anemia (eg, iron-deficiency, hemolytic
hypersplenism)
Iron-deficiency and iron-loading (sideroblastic) anemia,
thalassemia, lead poisoning, vitamin B 6 deficiency
Megaloblastic anemia, alcoholism, liver disease, hemolytic
anemia (reticulocytes), hemolytic disease of newborn,
myeloma, leukemia, myelophthisic anemia, metastatic
carcinoma, hypothyroidism
Megaloblastic anemia, pernicious anemia, cancer
chemotherapy
Severe iron-deficiency and iron-loading (sideroblastic)
anemia, thalassemia, lead poisoning, transferrin deficiency

Any severe anemia (eg, megaloblastic, iron-deficiency,
myeloproliferative syndrome, hemolytic); certain shapes are
diagnostically helpful (see entries for Spherocytes,
Elliptocytes, Stomatocytosis, Sickle cells, Target cells,
Schistocytes, Burr cells, Acanthocytes and Teardrop cells)
Spherical cells without pale
Hereditary spherocytosis, Coombs'-positive hemolytic
centers; often small (ie,
anemia; small numbers are seen in any hemolytic anemia
microspherocytosis)
and after transfusion of stored blood
Oval cells—elongated
Hereditary elliptocytosis (>25% on smear), iron deficiency
Red cells with slitlike (instead of Congenital stomatocytosis, Rh-null disease, alcoholism,
circular) areas of central pallor liver disease, artifact
Crescent-shaped cells
Sickle cell disease (Hb S)
Cells with a dark center and
Liver disease, thalassemia, iron-deficiency anemia,
periphery and a clear ring in
hemoglobinopathies, (S, C, S-C, S-thalassemia), artifact
between
Irregularly contracted cells
Vasculitis, artificial heart valve, disseminated intravascular
(severe poikilocytosis),
coagulation, thrombocytopenia purpura and other
fragmented cells
microangiopathic anemias, toxins (lead, phenylhydrazine,
snake bite), severe burns, renal graft rejection, and march
hemoglobinuria
Burr-like cells, spinous
Usually artifactual, uremia, stomach cancer, pyruvate kinase
processes
deficiency
Small cells with thorny
Abetalipoproteinemia (hereditary acanthocytosis or
projections
Bassen-Kornzweig disease), postsplenectomy, hemolytic
anemia, alcohol cirrhosis, hepatitis of newborns,
malabsorption states
Cells shaped like teardrops
Myeloproliferative syndrome, myelophthisic anemia
(neoplastic, granulomatous, or fibrotic marrow infiltration),
thalassemia, pernicious anemia, tuberculosis
Erythrocytes with nuclei still
Hemolytic anemias, leukemias, myeloproliferative
present, normoblastic or
syndrome, polycythemia vera, myelophthisic anemia
megaloblastic
(neoplastic, granulomatous, or fibrotic marrow infiltration),
multiple myeloma, extramedullary hematopoiesis,
megaloblastic anemias, any severe anemia

Howell-Jolly bodies

Heinz inclusion bodies

Spherical purple bodies
(Wright's) within or on
erythrocytes, nuclear debris
Small round inclusions of
denatured hemoglobin seen
under phase microscopy or with
supravital staining
Siderotic granules, staining blue
with Wright or Prussian blue
stain
Purple, fine, ringlike,
intraerythrocytic structure
Punctate stippling when Wright
stained

Hyposplenism, postsplenectomy pernicious anemia,
thalassemia, sickle cell anemia, other hemolytic anemias

Congenital hemolytic anemias (eg, glucose-6-phosphate
dehydrogenase deficiency), hemolytic anemia secondary to
drugs (dapsone, phenacetin), thalassemia (Hb H),
hemoglobinopathies (Hb Zurich, Koln, Ube, I, and so on)
Pappenheimer bodies
Iron-loading anemias (eg, sideroblastic anemia),
(siderocytes)
hyposplenism, lead poisoning, iron overload
(hemochromatosis)
Cabot's rings
Pernicious anemia, lead poisoning, severe hemolytic
anemia
Basophilic stippling
Hemolytic anemia, punctate stippling seen in lead poisoning
(mitochondrial RNA and iron), thalassemia, megaloblastic
anemia, alcoholism
Rouleaux
Aggregated erythrocytes
Multiple myeloma, Waldenström's macroglobulinemia, cord
regularly stacked on one
blood, pregnancy, hypergammaglobulinemia,
another—“rows of coins”
hyperfibrinogenemia
Polychromatophilia (called RBCs containing RNA, staining a Hemolytic anemia, blood loss, uremia, after treatment of
reticulocyes when stained pinkish-blue color; stains
iron-deficiency or megaloblastic anemia
with supravital stain)
supravitally as reticular network
with new methylene blue

NOTE
Not seen with Wright's stain. Must do supravital stain.
Red Blood Cell Count (RBC; Erythrocyte Count)
The main function of the red blood cell (RBC or erythrocyte) is to carry oxygen from the lungs to the body tissues and to
transfer carbon dioxide from the tissues to the lungs. This process is achieved by means of the Hb in the RBCs, which
combines easily with oxygen and carbon dioxide and gives arterial blood a bright red appearance. To enable use of the
maximal amount of Hb, the RBC is shaped like a biconcave disk; this affords more surface area for the Hb to combine
with oxygen. The cell is also able to change its shape when necessary to allow for passage through the smaller
capillaries.
The RBC test, an important measurement in the evaluation of anemia or polycythemia, determines the total number of
erythrocytes in a microliter (cubic millimeter) of blood.
Reference Values
Normal See Table 2.3
Table 2.3 Normal Values for Red Blood Cells
Men

4.2–5.4 × 10 6/mm 3 or × 10 12/L (average, 4.8)

Women

3.6–5.0 × 10 6/mm 3 or × 10 12/L (average, 4.3)

Children
Birth–2 wk

4.1–6.1 × 10 6/mm 3 × 10 12/L

2–8 wk

4.0–6.0 × 10 6/mm 3 × 10 12/L

2–6 mo

3.8–5.6 × 10 6/mm 3 × 10 12/L

6 mo–1 y

3.8–5.2 × 10 6/mm 3 × 10 12/L

1–6 y

3.9–5.3 × 10 6/mm 3 × 10 12/L

6–16 y

4.0–5.2 × 10 6/mm 3 × 10 12/L

16–18 y

4.2–5.4 × 10 6/mm 3 × 10 12/L

>18 y (males) 4.5–5.5 × 10
>18 y (females) 4.0–5.0 × 10

6

/mm 3 × 10 12/L

6

/mm 3 × 10 12/L

Procedure
1. Obtain 5 mL of EDTA-anticoagulated venous blood. Place the specimen in a biohazard bag.
2. Remember that automated electronic devices are generally used to determine the number of RBCs.
3. Note patient age and time of day on the laboratory slip.
Clinical Implications
1. Decreased RBC values occur in:
a. Anemia, a condition in which there is a reduction in the number of circulating erythrocytes, the amount of Hb, or
the volume of packed cells (Hct). Anemia is associated with cell destruction, blood loss, or dietary insufficiency

of iron or of certain vitamins that are essential in the production of RBCs. See Chart 2.1 on page 79 for a
classification of anemias based on their underlying mechanisms and the test for reticulocyte count for a
discussion of the purpose and clinical implications of the reticulocyte count.
b. Disorders such as:
1. Hodgkin's disease and other lymphomas
2. Multiple myeloma, myeloproliferative disorders, leukemia
3. Acute and chronic hemorrhage
4. Lupus erythematosus
5. Addison's disease
6. Rheumatic fever
7. Subacute endocarditis, chronic infection
8. This list is not meant to be all inclusive.
2. Erythrocytosis (increased RBC) occurs in:
a. Primary erythrocytosis
1. Polycythemia vera (myeloproliferative disorder)
2. Erythremic erythrocytosis (increased RBC production in bone marrow)
b. Secondary erythrocytosis
1. Renal disease
2. Extrarenal tumors
3. High altitude
4. Pulmonary disease
5. Cardiovascular disease
6. Alveolar hypoventilation
7. Hemoglobinopathy
8. Tobacco/carboxyhemoglobin
c. Relative erythrocytosis (decrease in plasma volume)
1. Dehydration (vomiting, diarrhea)
2. Gaisböck's syndrome

Clinical Alert
Refer to page 76 for a discussion of the combined clinical implications of decreased RBC, Hct, and Hb values. The
same underlying conditions cause a decrease in each of these three tests of erythrocyte production.

Clinical Alert
Please refer to page 75 for a discussion of the combined clinical implications of increased RBC, Hct, and Hb values.
The same underlying conditions cause an increase in each of these three tests of erythrocyte production.
Interfering Factors
1. Posture: when a blood sample is obtained from a healthy person in a recumbent position, the RBC is 5% lower. (If
the patient is anemic, the count will be lower still.)
2. Dehydration: hemoconcentration in dehydrated adults (caused by severe burns, untreated intestinal obstruction,
severe persistent vomiting, or diuretic abuse) may obscure significant anemia.
3. Age: the normal RBC of a newborn is higher than that of an adult, with a rapid drop to the lowest point in life at 2 to
4 months. The normal adult level is reached at age 14 years and is maintained until old age, when there is a
gradual drop (see normal values).
4. Falsely high counts may occur because of prolonged venous stasis during venipuncture.
5. Stress can cause a higher RBC.
6. Altitude: the higher the altitude, the greater the increase in RBC. Decreased oxygen content of the air stimulates
the RBC to rise (erythrocytosis).
7. Pregnancy: there is a relative decrease in RBC when the body fluid increases in pregnancy, with the normal
number of erythrocytes becoming more diluted.
8. There are many drugs that may cause decreased or increased RBC. See Appendix J for drugs that affect test
outcomes.
9. The EDTA blood sample tube must be at least three fourths filled or values will be invalid because of cell shrinkage
caused by the anticoagulant.
10. The blood sample must not be clotted (even slightly) or the values will be invalid.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Refer to standard pretest care for hemogram, CBC, and differential count on page 47.
3. Have the patient avoid extensive exercise, stress, and excitement before the test. These cause elevated counts of
doubtful clinical value.
4. Avoid overhydration or dehydration, if possible; either causes invalid results. If patient is receiving IV fluids or
therapy, note on requisition.
5. Note any medications patient is taking.
6. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately for anemia and erythrocytosis.
2. Refer to standard posttest care for hemogram, CBC, and differential count on page 47.

3. See Chapter 1 guidelines for safe, effective, informed posttest care .
4. Resume normal activities and diet.
Hematocrit (Hct); Packed Cell Volume (PCV)
The word hematocrit means “to separate blood,” which underscores the mechanism of the test because the plasma and
blood cells are separated by centrifugation.
The Hct test is part of the CBC. This test indirectly measures the RBC mass. The results are expressed as the
percentage by volume of packed RBCs in whole blood (PCV). It is an important measurement in the determination of
anemia or polycythemia.
Reference Values
Normal Women: 36%–48% or 0.36–0.48 Men: 42%–52% or 0.42–0.52 Children: 0–2 weeks: 44%–64% or 0.44–0.64 2–8
weeks: 39%–59% or 0.39–0.59 2–6 months: 35%–49% or 0.35–0.49 6 months–1 year: 29%–43% or 0.29–0.43 1–6
years: 30%–40% or 0.30–0.40 6–16 years: 32%–42% or 0.32–0.42 16–18 years: 34%–44% or 0.34–0.44

NOTE
If blood is drawn from a capillary puncture and a microhematocrit is done, values are slightly higher.
Procedure
1. Observe standard precautions. When doing a capillary puncture (finger puncture), the microcapillary tube is filled
three fourths full with blood, directly from puncture site. These tubes are coated with an anticoagulative.
2. Centrifuge the tubes in a microcentrifuge and measure the height of packed cells in the tube.
3. Record the measurement as a percentage of the total amount of blood in the capillary tube.
4. Remember that an Hct can be done on automated hematology instruments, in which case a 5-mL
EDTA-anticoagulated venous blood sample is obtained.
Clinical Implications
1. Decreased Hct values are an indicator of anemia, a condition in which there is a reduction in the PVC. An Hct <30%
(<0.30) means that the patient is moderately to severely anemic. Decreased values also occur in the following
conditions:
a. Leukemias, lymphomas, Hodgkin's disease, myeloproliferative disorders
b. Adrenal insufficiency
c. Chronic disease
d. Acute and chronic blood loss
e. Hemolytic reaction: this condition may be found in transfusion of incompatible blood or as a reaction to
chemicals or drugs, infectious agents, or physical agents (eg, severe burns, prosthetic heart valves).
2. The Hct may or may not be reliable immediately after even a moderate loss of blood or immediately after
transfusion.
3. The Hct may be normal after acute hemorrhage. During the recovery phase, both the Hct and the RBC drop
markedly.
4. Usually, the Hct parallels the RBC when the cells are of normal size. As the number of normal-sized erythrocytes
increases, so does the Hct.
a. However, for the patient with microcytic or macrocytic anemia, this relationship does not hold true.
b. If a patient has iron-deficiency anemia with small RBCs, the Hct decreases because the microcytic cells pack to
a smaller volume. The RBC, however, may be normal or higher than normal.
5. Increased Hct values occur in:
a. Erythrocytosis
b. Polycythemia vera
c. Shock, when hemoconcentration rises considerably

Clinical Alert
Please refer to page 76 for a discussion of the combined clinical implications of decreased Hct, Hb, and RBC values.
The same underlying conditions cause a decrease in each of these three tests of erythrocyte production.

Clinical Alert
Please refer to page 75 for a discussion of the combined clinical implications of increased Hct, Hb, and RBC values.
The same underlying conditions cause an increase in each of these three tests of erythrocyte production.
Interfering Factors
1. People living at high altitudes have high Hct values as well as high Hb and RBC.
2. Normally, the Hct slightly decreases in the physiologic hydremia of pregnancy.
3. The normal values for Hct vary with age and gender. The normal value for infants is higher because the newborn
has many macrocytic red cells. Hct values in females are usually slightly lower than in males.
4. There is also a tendency toward lower Hct values in men and women older than 60 years of age, corresponding to
lower RBC values in this age group.
5. Severe dehydration from any cause falsely raises the Hct.
Interventions

Pretest Patient Care
1. Explain test purpose and procedure.
2. Refer to standard pretest care for hemogram, CBC, and differential count on page 47. Also, see Chapter 1
guidelines for safe, effective, informed pretest care.

Clinical Alert
An Hct <20% (<0.20) can lead to cardiac failure and death; an Hct >60% (>0.60) is associated with spontaneous
clotting of blood.
Posttest Patient Aftercare
1. Interpret test results and monitor for anemia or polycythemia.
2. Refer to standard posttest care for hemogram, CBC, and differential count on page 47. Also, follow Chapter 1
guidelines for safe, effective, informed posttest care.
Hemoglobin (Hb)
Hb, the main component of erythrocytes, serves as the vehicle for the transportation of oxygen and carbon dioxide. It is
composed of amino acids that form a single protein called globin, and a compound called heme, which contains iron
atoms and the red pigment porphyrin. It is the iron pigment that combines readily with oxygen and gives blood its
characteristic red color. Each gram of Hb can carry 1.34 mL of oxygen per 100 mL of blood. The oxygen-combining
capacity of the blood is directly proportional to the Hb concentration rather than to the RBC because some RBCs contain
more Hb than others. This is why Hb determinations are important in the evaluation of anemia.
The Hb determination is part of a CBC. It is used to screen for disease associated with anemia, to determine the severity
of anemia, to monitor the response to treatment for anemia, and to evaluate polycythemia.
Hb also serves as an important buffer in the extracellular fluid. In tissue, the oxygen concentration is lower, and the
carbon dioxide level and hydrogen ion concentration are higher. At a lower pH, more oxygen dissociates from Hb. The
unoxygenated Hb binds to hydrogen ion, thereby raising the pH. As carbon dioxide diffuses into the RBC, carbonic
anhydrase converts carbon dioxide to bicarbonate and protons. As the protons are bound to Hb, the bicarbonate ions
leave the cell. For every bicarbonate ion leaving the cell, a chloride ion enters. The efficiency of this buffer system
depends on the ability of the lungs and kidneys to eliminate, respectively, carbon dioxide and bicarbonate. Refer to the
discussion of arterial blood gases in Chapter 14.
Reference Values
Normal Women: 12.0–16.0 g/dL or 120–160 g/L Men: 14.0–17.4 g/dL or 140–174 g/L Children: 0–2 weeks: 14.5–24.5
g/dL or 145–245 g/L 2–8 weeks: 12.5–20.5 g/dL or 125–205 g/L 2–6 months: 10.7–17.3 g/dL or 107–173 g/L 6 months–1
year: 9.9–14.5 g/dL or 99–145 g/L 1–6 years: 9.5–14.1 g/dL or 95–141 g/L 6–16 years: 10.3–14.9 g/dL or 103–149 g/L
16–18 years: 11.1–15.7 g/dL or 111–157 g/L
Procedure
1. Obtain a venous blood EDTA-anticoagulated sample of 5 mL. Fill the Vacutainer tube at least three fourths full.
Automated electronic devices are generally used to determine the Hb; however, a manual colorimetric procedure is
also widely used.
2. Do not allow the blood sample to clot, or the results will be invalid. Place the specimen in a biohazard bag.
Clinical Implications
1. Decreased Hb levels are found in anemia states (a condition in which there is a reduction of Hb, Hct, and/or RBC
values). The Hb must be evaluated along with the RBC and Hct.
a. Iron deficiency, thalassemia, pernicious anemia, hemoglobinopathies
b. Liver disease, hypothyroidism
c. Hemorrhage (chronic or acute)
d. Hemolytic anemia caused by:
1. Transfusions of incompatible blood
2. Reactions to chemicals or drugs
3. Reactions to infectious agents
4. Reactions to physical agents (eg, severe burns, artificial heart valves)
5. Various systemic diseases:
a. Hodgkin's disease
b. Leukemia
c. Lymphoma
d. SLE
e. Carcinomatosis
f. Sarcoidosis
g. Renal cortical necrosis
h. This list is not meant to be all inclusive.
2. Increased Hb levels are found in:
a. Polycythemia vera
b. Congestive heart failure
c. Chronic obstructive pulmonary disease (COPD)
3. Variation in Hb levels:

a. Occurs after transfusions, hemorrhages, burns. (Hb and Hct are both high during and immediately after
hemorrhage.)
b. The Hb and Hct provide valuable information in an emergency situation if they are interpreted not in an isolated
fashion but in conjunction with other pertinent laboratory data.

Clinical Alert
Please refer to page 76 for a discussion of the combined clinical implications of decreased Hb, Hct, and RBC values.
The same underlying conditions cause a decrease in each of these three tests of erythrocyte production.

Clinical Alert
Please refer below for a discussion of the combined clinical implications of increased Hb, Hct, and RBC values. The
same underlying conditions cause an increase in each of these three tests of erythrocyte production.
Clinical Implications of Polycythemia: Increased RBC, Hct, and/or Hb Polycythemia is the term used to describe an
abnormal increase in the number of RBCs. Although there are several tests to directly determine the RBC mass, these
tests are expensive and somewhat cumbersome. For screening purposes, we rely on the Hct and Hb to evaluate
polycythemia indirectly. Polycythemias are classified as follows:
1. Relative polycythemia: an increase in Hb, Hct, or RBC caused by a decrease in the plasma volume (eg,
dehydration, spurious erythrocytosis from stress or smoking)
2. Absolute or true polycythemia:
a. Primary (eg, polycythemia vera, erythemic erythrocytosis)
b. Secondary
1. Appropriate (an appropriate bone marrow response to physiologic conditions)
a. Altitude
b. Cardiopulmonary disorder
c. Increased affinity for oxygen
2. Inappropriate (an overproduction of RBCs not necessary to deliver oxygen to the tissues)
a. Renal tumor or cyst
b. Hepatoma
c. Cerebellar hemangioblastoma
Clinical Implications of Anemia: Decreased RBC, Hct, and/or Hb Anemia is the term used to describe a condition in
which there is a reduction in the number of circulating RBCs, the amount of Hb, and/or volume of packed cells (Hct). A
pathophysiologic classification of anemias based on their underlying mechanisms follows. Anemias are further explained
in Chart 2.1. Anemias are classified as follows:
1. Hypoproliferative anemias (inadequate production of RBCs):
a. Marrow aplasias
b. Myelophthisic anemia
c. Anemia with blood dyscrasias
d. Anemia of chronic disease
e. Anemia with organ failure
2. Maturation defect anemias:
a. Cytoplasmic: hypochromic anemias
b. Nuclear: megaloblastic anemias
c. Combined: myelodysplastic syndromes
3. Hyperproliferative anemias (decreased Hb or Hct despite an increased production of RBCs):
a. Hemorrhagic: acute blood loss
b. Hemolytic: a premature, accelerated destruction of RBCs
1. Immune hemolysis
2. Primary membrane
3. Hemoglobinopathies
4. Toxic hemolysis (physical-chemical)
5. Traumatic or microangiopathic hemolysis
6. Hypersplenism
7. Enzymopathies
8. Parasitic infections
4. Dilutional anemias:
a. Pregnancy
b. Splenomegaly
Interfering Factors
1.
2.
3.
4.
5.

People living at high altitudes have increased Hb values as well as increased Hct and RBC.
Excessive fluid intake causes a decreased Hb.
Normally, the Hb is higher in infants (before active erythropoiesis begins).
Hb is normally decreased in pregnancy as a result of increased plasma volume.
There are many drugs that may cause a decreased Hb. Drugs that may cause an increased Hb include gentamicin
and methyldopa.
6. Extreme physical exercise causes increased Hb.
Interventions

Pretest Patient Care
1. Explain test purpose and procedure. Assess medication history.
2. Refer to standard pretest care for hemogram, CBC, and differential count on page 47. Also, see Chapter 1
guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test results and monitor appropriately for anemia or polycythemia.
2. Refer to standard posttest care for hemogram, CBC, and differential count on page 47. Also, follow Chapter 1
guidelines for safe, effective, informed posttest care.

Clinical Alert
The panic Hb value is <5.0 g/dL (<50 g/L), a condition that leads to heart failure and death. A value >20 g/dL (>200
g/L) leads to clogging of the capillaries as a result of hemoconcentration.
Red Blood Cell Indices
The red cell indices define the size and Hb content of the RBC and consist of the mean corpuscular volume (MCV), the
mean corpuscular hemoglobin concentration (MCHC), and the mean corpuscular hemoglobin (MCH).
The RBC indices are used in differentiating anemias. When they are used together with an examination of the
erythrocytes on the stained smear, a clear picture of RBC morphology may be ascertained. On the basis of the RBC
indices, the erythrocytes can be characterized as normal in every respect or as abnormal in volume or Hb content. In
deficient states, the anemias can be classified by cell size as macrocytic, normocytic, or microcytic, or by cell size and
color as microcytic hypochromic.
Procedure
1. Remember that these are calculated values. An explanation of each measurement follows.
2. Obtain 5 mL EDTA blood so that RBC, Hb, and Hct determinations can be done for calculations.
Interventions
Pretest Patient Care for MCV, MCHC, and MCH
1. Explain the purpose and procedure for testing. Assess for possible causes of anemia. No fasting is required.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare for MCV, MCHC, and MCH
1. Interpret test results and monitor appropriately for anemia. Counsel appropriately for proper diet, medication,
related hormone and enzyme problems, and genetically linked disorders.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Mean Corpuscular Volume (MCV)
Individual cell size is the best index for classifying anemias. This index expresses the volume occupied by a single
erythrocyte and is a measure in cubic micrometers (femtoliters, or fL) of the mean volume. The MCV indicates whether
the red blood cell size appears normal (normocytic), smaller than normal (<82 µm 3 , microcytic), or larger than normal
(>100 µm 3 , macrocytic).
Reference Values
Normal 82–98 mm 3 or 82–98 fL (higher values in infants and newborns and for elderly patients)
Procedure
1. Calculate the MCV from the RBC count (the number of cells per cubic millimeter of blood) and the Hct (the
proportion of the blood occupied by the RBCs).
2. Use the following formula:

Clinical Implications The MCV results are the basis of the classification system used to evaluate an anemia. The
categorizations shown in Chart 2.1 aid in orderly investigation.

Chart 2.1 Anemias Characterized by Deficient Hemoglobin Synthesis
Microcytic Anemias (MCV 50–82 fL)
DISORDERS OF IRON METABOLISM Iron-deficiency anemia: the most prevalent worldwide cause of anemia; the
major causes are dietary inadequacy, malabsorption, increased iron loss, and increased iron requirements Anemia of
chronic disease, hereditary atransferrinemia Congenital hypochromic-microcytic anemia with iron overload
(Shahidi-Nathan-Diamond syndrome)
DISORDERS OF PORPHYRIN AND HEME SYNTHESIS Acquired sideroblastic anemias Idiopathic refractory
sideroblastic anemia, complicating other diseases associated with drugs or toxins (ethanol, isoniazid, lead) Hereditary
sideroblastic anemias X chromosome–linked, autosomal anemias
DISORDERS OF GLOBIN SYNTHESIS Thalassemias, hemoglobinopathies, characterized by unstable hemoglobins
Normocytic Normochromic Anemias (MCV 82–98 fL)
ANEMIA WITH APPROPRIATE BONE MARROW RESPONSE Acute posthemorrhagic anemia Hemolytic anemia (may
be macrocytic when there is pronounced reticulocytosis)
ANEMIA WITH IMPAIRED MARROW RESPONSE
Marrow hypoplasia Aplastic anemia, pure red cell aplasia
Marrow infiltration Infiltration by malignant cells, myelofibrosis, inherited storage diseases
Decreased erythropoietin production Kidney and liver disease, endocrine deficiencies, malnutrition, anemia of
chronic disease
Macrocytic Anemias (MCV 100–150 fL)
COBALAMIN (B 12) DEFICIENCY
Decreased ingestion Lack of animal products, strict vegetarianism
Impaired absorption Intrinsic factor deficiency, pernicious anemia, gastrectomy (total or partial), destruction of gastric
mucosa by caustics, anti-intrinsic factor antibody in gastric juice, abnormal intrinsic factor molecule, intrinsic intestinal
disease, familial selective malabsorption (Imerslünd's syndrome), ileal resection, ileitis, sprue, celiac disease,
infiltrative intestinal disease (eg, lymphoma, scleroderma) drug-induced malabsorption
Competitive parasites Fish tapeworm infestations ( Diphyllobothrium latum); bacteria in diverticulum of bowel, blind
loops
Increased requirements Chronic pancreatic disease, pregnancy, neoplastic disease, hyperthyroidism
Impaired utilization Enzyme deficiencies, abnormal serum cobalamin binding protein, lack of transcobalamin II,
nitrous oxide administration
FOLATE DEFICIENCY
Decreased ingestion Lack of vegetables, alcoholism, infancy
Impaired absorption Intestinal short circuits, steatorrhea, sprue, celiac disease, intrinsic intestinal disease,
anticonvulsants, oral contraceptives, other drugs
Increased requirement Pregnancy, infancy, hypothyroidism, hyperactive hematopoiesis, neoplastic disease,
exfoliative skin disease
Impaired utilization Folic acid antagonists: methotrexate, triamterene, trimethoprim, enzyme deficiencies
Increased loss Hemodialysis
UNRESPONSIVE TO COBALAMIN OR FOLATE
Metabolic inhibitors Purine synthesis: 6-mercaptopurine, 6-thioguanine, azathioprine Pyrimidine synthesis:
6-azauridine Thymidylate synthesis: methotrexate, 5-fluorouracil Deoxybonucleotide synthesis: hydroxyurea,
cytarabine, severe iron deficiency
Inborn errors Lesch-Nyhan syndrome, hereditary orotic aciduria, deficiency of formiminotransferase,
methyltransferase, others
Interfering Factors
1. Mixed (bimorphic) population of macrocytes and microcytes can result in a normal MCV. Examination of the blood
film confirms this.
2. Increased reticulocytes can increase the MCV.
3. Marked leukocytosis increases the MCV.
4. Marked hyperglycemia increases MCV.
5. Cold agglutinins increase MBV.
Interventions
Pretest Patient Care
1. Explain test purposes and procedures.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes; counsel and monitor appropriately.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Mean Corpuscular Hemoglobin Concentration (MCHC)
The MCHC measures the average concentration of Hb in the RBCs. The MCHC is most valuable in monitoring therapy

for anemia because the two most accurate hematologic determinations (Hb and Hct) are used in its calculation.
Reference Values
Normal 32–36 g/dL or 320–360 g/L
Procedure
1. Remember that the MCHC is a calculated value. It is an expression of the average concentration of Hb in the red
blood cells and, as such, represents the ratio of the weight of Hb to the volume of the erythrocyte.
2. Use the following formula:

Clinical Implications
1. Decreased MCHC values signify that a unit volume of packed RBCs contains less Hb than normal. Hypochromic
anemia (MCHC <30 g/dL) occurs in:
a. Iron deficiency
b. Microcytic anemias, chronic blood loss anemia
c. Some thalassemias
2. Increased MCHC values (RBCs cannot accommodate more than 37 g/dL or 370 g/L Hb) occur in:
a. Spherocytosis (hereditary)
b. Newborns and infants
Interfering Factors
1. The MCHC may be falsely high in the presence of lipemia, cold agglutinins, or rouleaux and with high heparin
concentrations.
2. The MCHC cannot be greater than 37 g/dL (370 g/L) because the RBC cannot accommodate more than 37 g/dL
(370 g/L) Hb. (Check for errors in calculation or in Hb determination. The MCHC can be used for laboratory quality
control.)
Interventions
Pretest Patient Care
1. Explain test purposes and procedures.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes; counsel and monitor appropriately.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Mean Corpuscular Hemoglobin (MCH)
The MCH is a measure of the average weight of Hb per RBC. This index is of value in diagnosing severely anemic
patients.
Reference Values
Normal 26–34 pg/cell or 0.40–0.53 fmol/cell (normally higher in newborns and infants)
Procedure The MCH is a calculated value. The average weight of Hb in the RBC is expressed as picograms of Hb per
RBC. The formula is:

Clinical Implications
1. An increase of the MCH is associated with macrocytic anemia and newborns.
2. A decrease of the MCH is associated with microcytic anemia.
Interfering Factors
1.
2.
3.
4.

Hyperlipidemia falsely elevates the MCH.
WBC >50,000/mm 3 falsely raises the Hb value and therefore falsely elevates the MCH.
High heparin concentrations falsely elevate the MCH.
Cold agglutinins falsely elevates MCH.

Interventions
Pretest Patient Care
1. Explain test purposes and procedures.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.

Posttest Patient Aftercare
1. Interpret test outcomes; counsel and monitor appropriately.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Red Cell Size Distribution Width (RDW)
This automated method of measurement is helpful in the investigation of some hematologic disorders and in monitoring
response to therapy. The RDW is essentially an indication of the degree of anisocytosis (abnormal variation in size of
RBCs). Normal RBCs have a slight degree of variation.
Reference Values
Normal 11.5–14.5 coefficient of variation (CV) of red cell size
Procedure
1. Remember that the CV of RDW is determined and calculated by the analyzer.
2. Use the CV of RDW with caution and not as a replacement for other diagnostic tests.
3. Use the following calculation:

Clinical Implications
1. The RDW can be helpful in distinguishing uncomplicated heterozygous thalassemia (low MCV, normal RDW) from
iron-deficiency anemia (low MCV, high RDW).
2. The RDW can be helpful in distinguishing anemia of chronic disease (low-normal MCV, normal RDW) from early
iron-deficiency anemia (low-normal MCV, elevated RDW).
3. Increased RDW occurs in:
a. Iron deficiency
b. Vitamin B 12 or folate deficiency (pernicious anemia)
c. Abnormal Hb: S, S-C, or H
d. S-ß-thalassemia (homogeneous)
e. Immune hemolytic anemia
f. Marked reticulocytosis
g. Fragmentation of RBCs
4. Normal RDW—normal in anemias with homogeneous red cell size
a. Chronic disease
b. Acute blood loss
c. Aplastic anemia
d. Hereditary spherocytosis
e. Hb E disease
f. Sickle cell disease
5. There is no known cause of a decreased RDW.
Interfering Factors
1. This test is not helpful for persons who do not have anemia.
2. Alcoholism elevates RDW.
3. Cold agglutinins
Interventions
Pretest Patient Care
1. Explain the purpose and procedure for testing. Assess for possible causes of anemia. No fasting is required.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test results and monitor appropriately for anemia. Counsel appropriately for proper diet, medication,
related hormone and enzyme problems, and genetically linked disorders.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Stained Red Cell Examination (Film; Stained Erythrocyte Examination)
The stained film examination determines variations and abnormalities in erythrocyte size, shape, structure, Hb content,
and staining properties. It is useful in diagnosing blood disorders such as anemia, thalassemia, and other
hemoglobinopathies. This examination also serves as a guide to therapy and as an indicator of harmful effects of
chemotherapy and radiation therapy. The leukocytes are also examined at this time.
Reference Values
Normal Size: normocytic (normal size, 7–8 µm) Color: normochromic (normal) Shape: normocyte (biconcave disk)
Structure: normocytes or erythrocytes (anucleated cells)
Procedure

1. Collect a 5-mL blood sample in EDTA. Stain a thin smear with Wright's stain and study under a microscope to
determine size, shape, and other characteristics of the RBCs.
2. Be aware that a capillary smear may also be used and may be preferred for detection of some abnormalities.
Clinical Implications Variations in staining, color, shape, and RBC inclusions are indicative of RBC abnormalities.

Clinical Alert
Marked abnormalities in size and shape of RBCs without a known cause are an indication for more complete blood
studies.
Interventions
Pretest Patient Care
1. Explain the purpose and procedure for testing. Assess for possible causes of anemia. No fasting is required.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome and monitor appropriately.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Reticulocyte Count
A reticulocyte—young, immature, nonnucleated RBC—contains reticular material (RNA) that stains gray-blue. Reticulum
is present in newly released blood cells for 1 to 2 days before the cell reaches its full mature state. Normally, a small
number of these cells are found in circulating blood. For the reticulocyte count to be meaningful, it must be viewed in
relation to the total number of erythrocytes (absolute reticulocyte count = % reticulocytes × erythrocyte count).
The reticulocyte count is used to differentiate anemias caused by bone marrow failure from those caused by hemorrhage
or hemolysis (destruction of RBCs), to check the effectiveness of treatment in pernicious anemia and folate and iron
deficiency, to assess the recovery of bone marrow function in aplastic anemia, and to determine the effects of radioactive
substances on exposed workers.
Reference Values
Normal Adults: 0.5%–1.5% of total erythrocytes (women may be slightly higher) Newborns: 3%–6% of total erythrocytes
(drops to adult levels in 1–2 months) Absolute count: 25–85 × 10 3/mm 3 or × 10 9 cells/L Reticulocyte index (RI): 1%
corrected reticulocyte count (CRC) Hematocrit correction for anemia: RI = reticulocyte count × (patient's Hct/45 × 1/1.85)
Procedure
1. Obtain a 5-mL EDTA-anticoagulated venous blood sample. Place the specimen in a biohazard bag.
2. Mix the blood sample with a supravital stain such as brilliant cresyl blue. Allow the stain to react with the blood, and
prepare a smear with this mixture and scan under a microscope. Count and calculate the reticulocytes.

3. Use the following formula:

45 = normal Hct; 1.85 = number of days for reticulocyte to mature
Clinical Implications
1. Increased reticulocyte count (reticulocytosis) means that increased RBC production is occurring as the bone
marrow replaces cells lost or prematurely destroyed. Identification of reticulocytosis may lead to the recognition of
an otherwise occult disease, such as hidden chronic hemorrhage or unrecognized hemolysis (eg, sickle cell
anemia, thalassemia). Increased levels are observed in the following:
a. Hemolytic anemia
1. Immune hemolytic anemia
2. Primary RBC membrane problems
3. Hemoglobinopathic and sickle cell disease
4. RBC enzyme deficits
5. Malaria
b. After hemorrhage (3 to 4 days)
c. After treatment of anemias
1. An increased reticulocyte count may be used as an index of the effectiveness of treatment.
2. After adequate doses of iron in iron-deficiency anemia, the rise in reticulocytes may exceed 20%.
3. There is a proportional increase when pernicious anemia is treated by transfusion or vitamin B 12 therapy.
2. Decreased reticulocyte count means that bone marrow is not producing enough erythrocytes; this occurs in:
a. Untreated iron-deficiency anemia
b. Aplastic anemia (a persistent deficiency of reticulocytes suggests a poor prognosis)
c. Untreated pernicious anemia
d. Anemia of chronic disease
e. Radiation therapy

f. Endocrine problems
g. Tumor in marrow (bone marrow failure)
h. Myelodysplastic syndromes
i. Alcoholism
3. Reticulocyte index implications
a. <2% indicates hypoproliferative component to anemia
b. >2%–3% indicates increased RBC production
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. Pretest and posttest care are the same as for the hemogram (see page 47).
Also, see Chapter 1 guidelines for safe, effective, informed pretest care.
2. Note medications. Some drugs cause aplastic anemia.
Posttest Patient Aftercare
1. Interpret test outcome and monitor appropriately for anemias.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Sedimentation Rate (Sed Rate); Erythrocyte Sedimentation Rate (ESR)
Sedimentation occurs when the erythrocytes clump or aggregate together in a column-like manner (rouleaux formation).
These changes are related to alterations in the plasma proteins. Normally, erythrocytes settle slowly because normal
RBCs do not form rouleaux.
The ESR is the rate at which erythrocytes settle out of anticoagulated blood in 1 hour. This test is based on the fact that
inflammatory and necrotic processes cause an alteration in blood proteins, resulting in aggregation of RBCs, which
makes them heavier and more likely to fall rapidly when placed in a special vertical test tube. The faster the settling of
cells, the higher the ESR. The ESR should not be used to screen asymptomatic patients for disease. It is most useful for
diagnosis of temporal arteritis, rheumatoid arthritis, and polymyalgia rheumatica. The sedimentation rate is not diagnostic
of any particular disease but rather is an indication that a disease process is ongoing and must be investigated. It is also
useful in monitoring the progression of inflammatory diseases; if the patient is being treated with steroids, the ESR will
decrease with clinical improvement.
Reference Values by Westergren's Method
Normal Men: 0–15 mm/h (over age 50 years: 0–20 mm/h) Women: 0–20 mm/h (over age 50 years: 0–30 mm/h) Children:
0–10 mm/h
Procedure
1. Obtain an EDTA-anticoagulated venous sample of 5 mL or 3.8% sodium citrate. Place the specimen in a biohazard
bag.
2. Suction the specimen into a graduated sedimentation tube and allow to settle for exactly 1 hour. The amount of
settling is the patient's ESR.
Clinical Implications
1. Increased ESR is found in:
a. All collagen diseases, SLE
b. Infections, pneumonia, syphilis, tuberculosis
c. Inflammatory diseases (eg, acute pelvic inflammatory disease)
d. Carcinoma, lymphoma, neoplasms
e. Acute heavy-metal poisoning
f. Cell or tissue destruction, myocardial infarction
g. Toxemia, pregnancy (third month to 3 weeks' postpartum)
h. Waldenström's macroglobulinemia, increased serum globulins
i. Nephritis, nephrosis
j. Subacute bacterial endocarditis
k. Anemia—acute or chronic disease
l. Rheumatoid arthritis, gout, arthritis, polymyalgia rheumatica
m. Hypothyroidism and hyperthyroidism
2. Normal ESR (no increase) is found in:
a. Polycythemia vera, erythrocytosis
b. Sickle cell anemia, Hb C disease
c. Congestive heart failure
d. Hypofibrinogenemia (from any cause)
e. Pyruvate kinase deficiency
f. Hereditary spherocytosis
g. Anemia
1. ESR is normal in iron-deficiency anemia
2. ESR is abnormal in anemia of chronic disease alone or in combination with iron-deficiency anemia and can
be used to differentiate these
h. Uncomplicated viral disease and infectious mononucleosis—normal
i. Active renal failure with heart failure—normal
j. Acute allergy—normal

k. Peptic ulcer—normal

Clinical Alert
Extreme elevation of the ESR is found with malignant lymphocarcinoma of colon or breast, myeloma, and rheumatoid
arthritis.
Interfering Factors
1. Allowing the blood sample to stand >24 hours before the test is started causes the ESR to decrease.
2. In refrigerated blood, the ESR is increased. Refrigerated blood should be allowed to return to room temperature
before the test is performed.
3. Factors leading to an increased ESR include:
a. The presence of fibrinogen, globulins, C-reactive protein, high cholesterol
b. Pregnancy after 12 weeks until about the fourth postpartum week
c. Young children
d. Menstruation
e. Certain drugs (eg, heparin, oral contraceptives; see Appendix J)
f. Anemia (low Hct)
g. Macrocytosis
4. The ESR may be very high (up to 60 mm/h) in apparently healthy women aged 70 to 89 years.
5. Factors leading to reduced ESR include:
a. High blood sugar, high albumin level, high phospholipids
b. Decreased fibrinogen level in the blood in newborns, hypofibrinogenemia
c. Certain drugs (eg, steroids, high-dose aspirin; see Appendix J)
d. High Hb and RBC—polycythemia
e. High WBC
f. Abnormal RBCs (eg, sickle cells, spherocytes, microcytosis)
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. Obtain appropriate medication history. Fasting is not necessary, but a fatty
meal can cause plasma alterations.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities and diet.
2. Interpret test outcome; counsel and monitor appropriately for rheumatic disorders and inflammatory conditions.
3. See Chapter 1 guidelines for safe, effective, informed posttest care .

TESTS FOR PORPHYRIA
Porphyrins are chemical intermediates in the synthesis of Hb, myoglobin, and other respiratory pigments called
cytochromes. They also form part of the peroxidase and catalase enzymes, which contribute to the efficiency of internal
respiration. Iron is chelated within porphyrins to form heme. Heme is then incorporated into proteins to become
biologically functional hemoproteins.
Tests of blood, urine, and stool are done to diagnose porphyria, an abnormal accumulation of porphyrins in body fluids.
Porphyrias are a group of diseases caused by a deficit in the enzymes involved in porphyrin metabolism and
abnormalities in the production of the metalloporphyrin heme. These tests are indicated in persons who have
unexplained neurologic manifestations, unexplained abdominal pain, cutaneous blisters, and/or the presence of a
relevant family history. Test results may identify clinical conditions associated with abnormal heme production, including
anemia and porphyria (abnormal accumulation of the porphyrins) associated with enzyme disorders that may be genetic
(hereditary) or acquired (eg, lead poisoning, alcohol). Accumulation of porphyrins occurs in blood plasma, serum,
erythrocytes, urine, and feces. A discussion of erythrocyte totals and fractionation of erythrocytes and plasma follows.
For details of urine, serum, and stool testing for porphyrias, see Chapter 3, Chapter 6, and Chapter 4, respectively.
Erythropoietic Porphyrins; Free Erythrocyte Protoporphyrin (FEP)
Normally, there is a small amount of excess porphyrin at the completion of heme synthesis. This excess is cell-free
erythrocyte protoporphyrin (FEP). The amount of FEP in the erythrocyte is elevated when the iron supply is diminished.
This test is useful in screening RBC disorders such as iron deficiency and lead exposure, especially in children 6 months
to 5 years of age. This is the test of choice to diagnose erythopoietic protoporphyria. This test should not be used for
screening for lead poisoning in children.
Reference Values
Normal <100 µg/dL of packed RBCs

NOTE
This depends on the method. Check with your laboratory.

Procedure
1. Obtain a 5-mL sample of anticoagulated venous blood. EDTA, or heparin, may be used. Place the specimen in a
biohazard bag.
2. Protect the blood sample from light.
3. Wash the cells and then test for porphyrins.
4. Be aware that the Hct must be known for test interpretation.
Clinical Implications
1. Increased FEP is associated with:
a. Iron-deficiency anemias (elevated before anemia)
b. Lead poisoning (chronic)
c. Halogenated solvents and many drugs (see Appendix J)
d. Anemia of chronic disease
e. Acquired idiopathic sideroblastic anemia (most cases)
f. Erythropoietic protoporphyria
2. FEP is normal in:
a. Thalassemia minor (and therefore can be used to differentiate this from iron deficiency and other disorders of
globin synthesis)
b. Pyridoxine-responsive anemia
c. Certain forms of sideroblastic anemia due to proximal block to protoporphyrin
Interventions
Pretest Patient Care
1. Explain test purpose and sampling procedure.
2. Note on laboratory slip or computer any medications the patient is taking that cause intermittent porphyria.
Discontinue such medications before testing (after checking with physician).
3. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Resume normal activities and diet.
2. Interpret test outcome and monitor appropriately for porphyria or lead poisoning.
3. See Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
The critical value is FEP >300 µg/dL.
Porphyrins; Fractionation of Erythrocytes and of Plasma
The primary porphyrins of erythrocytes are protoporphyrin, uroporphyrin, and coproporphyrin.
Fractionation of erythrocytes is used to differentiate congenital erythropoietic coproporphyria from erythropoietic
protoporphyria and to confirm a diagnosis of protoporphyria. This test establishes a specific type of porphyria by naming
the specific porphyrin in plasma. In persons with renal failure, plasma fractionation can help to determine whether the
porphyria is caused by a deficiency of uroporphyrinogenic decarboxylase or by failure of the renal system to excrete
porphyrinogens.
Reference Values
Normal The value is reported in micrograms per deciliter (µg/dL). Check with your laboratory for reference values.
1. Erythrocyte porphyrins:
a. Protoporphyrin: 16–60 µg/dL packed cells or 0.3–1.7 µmol/L
b. Uroporphyrin: <2 µg/dL or <24 nmol/L
c. Hepatocarboxylic: <1 µg/dL or <10 µg/L
d. Hexacarboxylic: <1 µg/dL or <10 µg/L
e. Pentacarboxylic: <1 µg/dL or <10 µg/L
f. Coproporphyrin: <1 µg/dL or <15 µg/L
2. Plasma porphyrins: Total porphyrins should not exceed 1.0 µg/dL or 12 nmol/L
Procedure
1. Draw a 5-mL sample of anticoagulated blood. EDTA or heparin can be used as an anticoagulant. Place the
specimen in a biohazard bag.
2. Protect the specimen from light.
Clinical Implications
1. Increased erythrocyte porphyrins are associated with primary porphyrias:
a. Congenital erythropoietic protoporphyria

b. Protoporphyria (autosomal dominant deficiency of heme synthetase)
c. Hereditary porphobilinogen synthase deficiency
d. Intoxication porphyria
2. Increased plasma porphyrins are associated with:
a. Congenital erythropoietic protoporphyria
b. Coproporphyria
c. Porphyria cutanea tarda
d. Parigate porphyria
e. Chronic renal failure porphyria
Interventions
Pretest Patient Care
1.
2.
3.
4.

Advise patient of test purpose.
Note on the requisition any drugs the patient is taking.
Before testing, discontinue drugs that are known to cause intermittent porphyria (after checking with physician).
See Chapter 1 guidelines for safe, effective, informed pretest care.

Posttest Patient Aftercare
1.
2.
3.
4.

Resume medications.
Interpret test outcome and monitor appropriately for porphyria or lead poisoning.
Caution persons diagnosed with porphyria (with cutaneous manifestations) to avoid sun exposure.
Advise persons diagnosed with porphyria (with neurologic symptoms) that attacks can be precipitated by infections,
various phases of the menstrual cycle, fasting states, and certain drugs. A listing of drugs (not all inclusive) that
may precipitate acute attacks follows:
a. Barbiturates
b. Chlordiazepoxide
c. Chloroquine
d. Chlorpropamide
e. Dichloralphenazone
f. Ergot preparations
g. Estrogens
h. Ethanol
i. Glutethimide
j. Griseofulvin
k. Hydantoins
l. Imipramine
m. Meprobamate
n. Methsuximide
o. Methyldopa
p. Sulfonamides
5. Follow Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
1. A blood test for uroporphyrinogen I synthase (also known as erythrocyte porphobilinogen deaminase) can be
done to identify persons at risk for acute intermittent porphyria, to detect latent-phase intermittent porphyria, and
to confirm the diagnosis during an acute episode.
2. The normal value is 5.3–9.2 nmol/L in women; 3.4–8.5 nmol/L in men. A value of <3.5 nmol/L is diagnostic of
acute intermittent porphyria.

ADDITIONAL TESTS FOR HEMOLYTIC ANEMIA
Several RBC enzyme and fragility tests can be done to screen, detect, and confirm the cause of chronic hemolytic
anemia. Many persons with hemolytic anemia have no clinical signs or symptoms. Abnormal test outcomes are
associated with inherited deficiencies, abnormal hemoglobins, and exposure to chemicals and drugs. Definitive test
results indicate some type of injury to the RBC, oxidated activity that interferes with normal Hb function, and/or increased
RBC fragility.
Pyruvate Kinase (PK)
PK deficiency is a genetic disorder characterized by a lowered concentration of adenosine triphosphate in the RBC and
consequential membrane defect. The result is a nonspherocytic, chronic hemolytic anemia. PK deficiency is the most
common and most important form of hemolytic anemia resulting from a deficiency of glycolytic enzymes in the RBC.
Reference Values
Normal 2.8–8.8 U/g Hb or 46.7–146.7 nkat/g Hb To convert to U/mL of packed RBCs: U/g Hb × 0.34 = U/mL packed
RBCs Check with your reference lab.
Procedure
1. Obtain a venous blood sample of at least 5 mL with EDTA or heparin anticoagulant.
2. Refrigerate immediately.

Clinical Implications PK is increased in:
1. Congenital PK deficiency: recessive, nonspherocytic hemolytic anemia. Patients tolerate anemia well because of
increased 2,3-diphosphoglycerate (2,3-DPG).
2. Acquired PK deficiency caused by (level returns to normal after treating underlying disorder):
a. Myelodysplastic disorders
b. Acute leukemias
c. Anemias
Interfering Factors In congenital PK, intravascular hemolysis increases during pregnancy or following use of oral
contraceptives.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. There should be no exercising before tests.
2. Withhold transfusion until after blood samples are drawn (especially with osmotic fragility).
3. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test results and monitor appropriately for hemolytic anemia, hypoxia, or polycythemia.
2. Splenectomy is indicated when anemia is severe enough to require transfusions.
3. Follow Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
Many prescribed drugs interfere with the normal functioning of hemoglobin in susceptible persons, especially
sulfonamides, antipyretics, analgesics, large doses of vitamin K, and nitrofurans.
Erythrocyte Fragility (Osmotic Fragility and Autohemolysis)
Spherocytes of any origin (including conditions other than hereditary spherocytosis) are more susceptible than normal
RBCs to hemolysis in dilute (hypotonic) saline and show increased osmotic fragility. Generally, fully expanded cells
(spheroidal cells or spherocytes) have increased osmotic fragility, whereas cells with higher surface area-to-volume
ratios (eg, thin cells, hypochromic cells, tart cells) have decreased osmotic fragility.
In hereditary spherocytosis, the osmotic fragility test may be normal initially. There-fore, the test is incubated at 37°C for
24 hours, at which time the test is positive for hereditary spherocytosis.
Reference Values
Normal Immediate test: Hemolysis begins at 0.5% NaCl Hemolysis complete at 0.3% NaCl 24-hour incubation:
Hemolysis begins at 0.7% NaCl Hemolysis complete at 0.4% NaCl
Procedure
1. Obtain a 7-mL venous blood sample using heparin as anticoagulant. Place the specimen in a biohazard bag.
2. Expose erythrocytes to varying dilutions of sodium chloride. Read hemolysis on a spectrophotometer (optical
density measurement). Perform studies and measure both before and after 24-hour incubation of the RBCs.
Clinical Implications
1. Increased osmotic fragility is found in:
a. Hemolytic anemia (acquired immune)
b. Hereditary spherocytosis (stomatocytosis)
c. Hemolytic disease of the newborn
d. Malaria
e. Severe pyruvate kinase deficiency
2. Decreased osmotic fragility occurs in:
a. Iron-deficiency anemia (macrocytic hypochromic)
b. Thalassemias
c. Asplenia (postsplenectomy)
d. Liver disease (obstructive jaundice)
e. Reticulocytosis
f. Hemoglobinopathies, especially Hb C, Hb S
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. There should be no exercising before tests.
2. Withhold transfusion until after blood samples are drawn (especially with osmotic fragility).
3. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare

1. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
2. Be aware that the usual treatment for hereditary spherocytosis is splenectomy, which removes the agent of RBC
destruction and prevents complications such as aplastic anemia.
Glucose-6-Phosphate Dehydrogenase (G6PD)
G6PD is a sex-linked disorder. The major variants occur in specific ethnic groups. In a large group of African American
men, the incidence of type A G6PD deficiency was found to be 11%. Approximately 20% of African American women are
heterozygous. With some variants, there is chronic lifelong hemolysis, but more commonly, the condition is asymptomatic
and results only in susceptibility to acute hemolytic episodes, which may be triggered by certain drugs, ingestion of fava
beans, or viral or bacterial infection. G6PD hemolysis is associated with formation of Heinz bodies in peripheral RBCs.
The other two most common types are Mediterranean, which is common in Iraqis, Kurds, Sephardic Jews, and Lebanese
and less common in Greeks, Italians, Turks, and North Africans, and the MAHIDOL variant, which is common in
Southeast Asians (22% males).
Reference Values
Normal G6PD screen: G6PD detected Adults: 8.6–18.6 U/g Hb or 0.14–0.31 nkat/g Hb Children: 6.4–15.6 U/g Hb or
0.11–0.26 nkat/g Hb Newborns: have values up to 50% higher than adults If done as a screening test, G6PD activity is
reported as within normal limits. Different laboratories have different ways of reporting. To convert U/g Hb to U/mL of
RBCs: U/g Hb × 0.34 = U/mL of RBCs
Procedure
1. Obtain a blood sample of at least 5 mL, using EDTA or heparin anticoagulant.
2. Place on ice in a biohazard bag. Perform a G6PD screen first.
Clinical Implications
1. G6PD is decreased in:
a. G6Pd deficiency (causes hemolytic episodes after exposure to certain drugs and fava beans)
b. Congenital nonspherocytic anemia
c. Nonimmunologic hemolytic disease of the newborn (Asian and Mediterranean)
2. G6PD is increased in:
a. Untreated megaloblastic anemia (pernicious anemia)
b. Thrombocytopenia purpura
c. Hyperthyroidism
d. Viral hepatitis
Interfering Factors
1. Marked reticulocytosis may give a falsely high G6PD.
2. G6PD may be falsely normal for 6 to 8 weeks after a hemolytic episode, especially in black persons with the type A
variant. Retest after the patient recovers from the episode of anemia.

Clinical Alert
In G6PD-Mediterranean, G6PD levels are grossly deficient in all RBCs. Patients with this variant commonly experience
hemolysis induced by diabetic acidosis, infections, and oxidant drugs and potentially fatal hemolytic crises after
ingestion of fava beans.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. There should be no exercising before tests.
2. Withhold transfusion until after blood samples are drawn (especially with osmotic fragility).
3. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
2. Be aware that there are certain drugs and chemicals that should be avoided by persons with G6PD.
Heinz Bodies; Heinz Stain; Glutathione Instability
Heinz bodies are insoluble intracellular inclusions of Hb attached to RBC membrane. Heinz bodies are uncommon except
with G6PD deficiency immediately after hemolysis and in patients with unstable Hb variants.
Oxidative denaturation of the Hb molecule leads to Heinz body formation and is probably the mechanism for the
precipitation of unstable Hb. Heinz bodies are usually removed by the spleen; after splenectomy, they increase in the
peripheral blood and may appear in >50% of RBCs.
Reference Values
Normal Not seen in normal patients

Procedure
1. Obtain a venous blood sample, anticoagulated with heparin or EDTA. Place the specimen in a biohazard bag.
2. Mix cells with a supravital stain and examine microscopically. They stain as pale blue bodies, as opposed to the
dark purple RNA in reticulocytes.
Clinical Implications
1. Increased Heinz bodies are found in:
a. G6PD deficiency, especially after hemolysis
b. Congenital Heinz body hemolytic anemia
c. Unstable Hb variants (eg, Hb Zurich, Hb Philly)
d. Homozygous ß-thalassemia
2. Heinz bodies are found in blood of normal persons who have been poisoned by certain drugs used in treatment
protocols (eg, chlorates, phenylhydrazine, primaquine).
3. Heinz bodies are present in some newborns or in splenectomized patients.
Interfering Factors See Appendix J for drugs that affect test outcomes.
Interventions
Pretest Patient Care
1. Explain test purposes and procedures.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes; counsel and monitor appropriately.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
2,3-Diphosphoglycerate (2,3-DPG)
2,3-DPG assists in transporting oxygen in the RBC. 2,3-DPG increases in response to hypoxia or anemia and decreases
in acidosis. Levels are lower in newborns and even lower in premature newborns.
Reference Values
Normal Adults: 10.4–14.2 µmol/g Hb or 3.6–4.8 µmol/mL RBCs Check with your reference lab.
Procedure
1. Obtain a venous blood sample of at least 3 mL, anticoagulated with heparin.
2. Place on ice immediately (2,3-DPG is stable for only 2 hours) and transport to laboratory as soon as possible in a
biohazard bag.
Clinical Implications
1. Increased 2,3-DPG occurs in:
a. Emphysema, cystic fibrosis with pulmonary involvement (conditions of hypoxia)
b. Cyanotic heart disease
c. Pulmonary vascular disease
d. Sickle cell anemia, iron-deficiency anemia
e. Pyruvate kinase deficiency
f. Hyperthyroidism
g. Chronic renal failure
h. Cirrhosis
2. Decreased 2,3-DPG occurs in:
a. Polycythemia vera
b. Respiratory distress syndrome
c. 2,3-DPG deficiency
d. Hexokinase deficiency
Interfering Factors
1. High altitude increases 2,3-DPG.
2. Exercise increases 2,3-DPG.

Clinical Alert
If blood with decreased 2,3-DPG is used for transfusion, the Hb may not release O 2 when needed.
Interventions
Pretest Patient Care for Tests for Hemolytic Anemia
1. Explain test purpose and procedure. There should be no exercising before tests.
2. Withhold transfusion until after blood samples are drawn (especially with osmotic fragility).

3. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare for Tests for Hemolytic Anemia
1. Interpret test results and monitor appropriately for hemolytic anemia, hypoxia, or polycythemia.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .

IRON TESTS
Iron (Fe), Total Iron-Binding Capacity (TIBC), and Transferrin Tests
Iron is necessary for the production of Hb. Iron is contained in several components. Transferrin (also called siderophilin),
a transport protein largely synthesized by the liver, regulates iron absorption. High levels of transferrin relate to the ability
of the body to deal with infections. Total iron-binding capacity (TIBC) correlates with serum transferrin, but the relation is
not linear. A serum iron test without a TIBC and transferrin determination has very limited value except in cases of iron
poisoning. Transferrin saturation is a better index of iron saturation; it is evaluated as follows:

The combined results of transferrin, iron, and TIBC tests are helpful in the differential diagnosis of anemia, in assessment
of iron-deficiency anemia, and in the evaluation of thalassemia, sideroblastic anemia, and hemochromatosis.
Reference Values
Normal Iron Adult men: 65–175 µg/dL or 11.6–31.3 µmol/L Adult women: 50–170 µg/dL or 9.0–30.4 µmol/L Children:
50–120 µg/dL or 9.0–21.5 µmol/L Newborns: 100–250 µg/dL or 17.9–44.8 µmol/L Total iron-binding capacity (TIBC) Men:
250–450 µg/dL or 44.8–76.1 µmol/L Women: 250–450 µg/dL or 44.8–76.1 µmol/L Transferrin Adults: 250–425 mg/dL or
2.5–4.2 g/L Children: 203–360 mg/dL or 2.0–3.6 g/L Newborns: 130–275 mg/dL or 1.3–2.7 g/L Transferrin (iron)
saturation Men: 10%–50% Women: 15%–50%
Procedure
1. Obtain a venous blood sample of 10 mL.
2. Place the specimen in a biohazard bag. Serum is needed for these tests.
Clinical Implications
1. Increased transferrin is observed in:
a. Iron-deficiency anemia (uncomplicated)
b. Pregnancy
c. Estrogen therapy
2. Decreased transferrin is found in:
a. Microcytic anemia of chronic disease
b. Protein deficiency or loss from burns or malnutrition
c. Chronic infection
d. Acute liver disease
e. Renal disease (nephrosis)
f. Genetic deficiency, hereditary atransferrinemia
g. Iron-overload states (hemochromatosis)
3. Decreased iron occurs in:
a. Iron-deficiency anemia
b. Chronic blood loss
c. Chronic diseases (eg, lupus, rheumatoid arthritis, chronic infections)
d. Third-trimester pregnancy and progesterone birth control pills
e. Remission of pernicious anemia
f. Inadequate absorption of iron
g. Hemolytic anemia (PNH)
4. Increased iron occurs in:
a. Hemolytic anemias, especially thalassemia, pernicious anemia in relapse (not hemolytic anemias)
b. Acute iron poisoning (children)
c. Iron-overload syndromes
d. Hemochromatosis, iron overload
e. Transfusions (multiple), intramuscular iron, inappropriate iron therapy
f. Acute hepatitis, liver damage
g. Vitamin B 6 deficiency
h. Lead poisoning
i. Acute leukemia
j. Nephritis
5. Increased TIBC is found in:
a. Iron deficiency
b. Pregnancy (late)
c. Acute and chronic blood loss
d. Acute hepatitis
6. Decreased TIBC is observed in:
a. Hypoproteinemia (malnutrition and burns)

b. Hemochromatosis
c. Non–iron-deficiency anemia (infection and chronic disease)
d. Cirrhosis of liver
e. Nephrosis and other renal diseases
f. Thalassemia
g. Hyperthyroidism
7. The iron saturation index is increased in:
a. Hemochromatosis
b. Increased iron intake
c. Thalassemia
d. Hemosiderosis
e. Acute liver disease
8. The iron saturation index is decreased in:
a. Iron-deficiency anemias
b. Malignancy (standard and small intestine)
c. Anemia of infection and chronic disease
d. Iron neoplasms
Interfering Factors
1.
2.
3.
4.
5.
6.
7.
8.

Many drugs affect test outcomes (see Appendix J).
Drugs that may cause increased iron include ethanol, estrogens, and oral contraceptives.
Drugs that may cause decreased iron include some antibiotics, aspirin, and testosterone.
Hemolysis of the blood sample interferes with testing.
Iron contamination of glassware used in testing can give high values.
Menstruation causes decreased iron; iron is elevated in the premenstrual period.
There is a diurnal variation in iron: normal values in the morning, lower in midafternoon, very low in the evening.
Serum iron and TIBC may be normal in iron-deficiency anemia if the Hb is >9.0 g/dL (or >90 g/L).

Interventions
Pretest Patient Care
1.
2.
3.
4.
5.
6.
7.

Explain test purpose and procedure.
Draw fasting blood in the morning, when levels are higher.
Draw iron sample before iron therapy is initiated or blood is transfused.
If the patient has received a transfusion, delay iron testing for 4 days.
Avoid any iron-chelating drug (eg, deferoxamine [Desferal]).
Avoid sleep deprivation and extreme stress, which cause lower iron levels.
Note on laboratory slip or computer screen whether the patient is taking oral contraceptives or estrogen therapy or
is pregnant.
8. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Resume normal activities.
2. Interpret test outcome and monitor appropriately. The combination of low serum iron, high TIBC, and high
transferrin levels indicates iron deficiency. Diagnosis of iron deficiency may lead further to detection of
adenocarcinoma of the gastrointestinal tract, a point that cannot be overemphasized. A significant minority of
patients with megaloblastic anemias (20%–40%) have coexisting iron deficiency. Megaloblastic anemia can
interfere with the interpretation of iron studies; repeat iron studies 1 to 3 months after folate or vitamin B 12
replacement.
3. Use Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
1. Critical iron values: intoxicated child, 280–2550 µg/dL or 50–456 µmol/L; fatally poisoned child, >1,800 µg/dL or
>322 µmol/L.
2. Symptoms of iron poisoning include abdominal pain, vomiting, bloody diarrhea, cyanosis, and convulsions.
Ferritin
Ferritin, a complex of ferric (Fe 2+ ) hydroxide and a protein, apoferritin, originates in the reticuloendothelial system.
Ferritin reflects the body iron stores and is the most reliable indicator of total-body iron status. A bone marrow
examination is the only better test. Bone marrow aspiration may be necessary in some cases, such as low-normal ferritin
and low serum iron in the anemia of chronic disease.
The ferritin test is more specific and more sensitive than iron concentration or TIBC for diagnosing iron deficiency.
Ferritin decreases before anemia and other changes occur.
Reference Values
Normal Men: 20–250 ng/mL or 20–250 µg/L With anemia of chronic disease: <100 ng/mL or <100 µg/L In absence of
inflammation: <20 ng/mL or <20 µg/L Women: 10–120 ng/mL or 10–120 µg/L With anemia of chronic disease: <20 ng/mL
or <20 µg/L In absence of inflammation: <10 ng/mL or <10 µg/L Children: 7–140 ng/mL or 7–140 µg/L Newborns: 25–200
ng/mL or 25–200 µg/L 1 month: 50–200 ng/mL or 50–200 µg/L 2–5 months: 50–200 ng/mL or 50–200 µg/L Serum

TfR-ferritin index: 1.5 in absence of anemia of chronic disease, 0.8 with anemia of chronic disease

NOTE
TfR is the transferrin receptor.
Procedure
1. Obtain a venous sample of 6 mL.
2. Place the specimen in a biohazard bag.

Ferritin, Iron, and Iron Saturation Changes in Anemias
Anemia
Ferritin Iron Iron Saturation
Hemorrhage, acute
N
D
D
Hemorrhage, chronic
D
D
D
Iron-deficiency
D
D
D
Aplastic
D
I
I
Megaloblastic
I
D
D
Hemolytic
I
I
I
Sideroblastic
I
I
I
Thalassemia, major
I
I
I
Thalassemia, minor
I
N/I
N/I
Bone marrow neoplasia
N/I
I
I
Uremia, nephrosis, or nephrotic syndrome N/I D/I
D
Liver disease
N/I N/I
N/I
Chronic diseases
I
D
D
N, no change; D, decrease; I, increase.

Clinical Implications
1. Decreased ferritin (<10 ng/mL or <10 µg/L) usually indicates iron-deficiency anemia.
2. Increased ferritin (>400 ng/mL or >400 µg/L) occurs in iron excess and in the following:
a. Iron overload from hemochromatosis or hemosiderosis
b. Oral or parenteral iron administration
c. Inflammatory diseases
d. Acute or chronic liver disease involving alcoholism
e. Acute myoblastic or lymphoblastic leukemia
f. Other malignancies (Hodgkin's disease, breast carcinoma, malignant lymphoma)
g. Hyperthyroidism
h. Hemolytic anemia, megaloblastic anemia, thalassemia, sideroblastic anemia
i. Renal cell carcinoma, end-stage renal disease
Interfering Factors
1.
2.
3.
4.
5.
6.

Recently administered radioactive medications cause spurious results.
Oral contraceptives and antithyroid therapy interfere with testing (see Appendix J).
Hemolyzed blood may cause high results.
Increases with age.
Higher in red-meat eaters than vegetarians.
Ferritin is not of value to evaluate iron stores in alcoholic persons with liver disease.

Interventions
Pretest Patient Care
1.
2.
3.
4.

Explain test purpose and procedure. Fasting is not necessary.
Radioactive medications may not be given for 3 to 4 days before testing.
Refrain from alcohol (higher levels of ferritin occur in alcoholism).
See Chapter 1 guidelines for safe, effective, informed pretest care.

Clinical Alert
Critical value: Iron deficiency: <10 mg/mL or <10 µg/L
Posttest Patient Aftercare
1. Resume normal activities.
2. Interpret test results and monitor appropriately for iron-deficiency anemia and ferritin increases. When iron and
TIBC tests are used together with ferritin, they can better distinguish between iron-deficiency anemia and the
anemia of chronic disease. Explain possible treatment with vitamin B 12 and folic acid.
3. See Chapter 1 guidelines for safe, effective, informed posttest care .

Iron Stain (Stainable Iron in Bone Marrow; Prussian Blue Stain)
In the bone marrow, normoblasts containing iron granules (stainable) are known as sideroblasts. Erythrocytes (RBCs)
that contain stainable iron are called siderocytes. Normally, about 33% of the normoblasts are sideroblasts. Other
storage iron is readily identifiable in monophages in bone marrow particles on the marrow slides.
The bone marrow iron stain is the gold standard of iron deficiency: the presence of iron rules out iron deficiency. Marrow
iron disappears before peripheral blood changes occur in iron-deficiency anemia. Only patients with decreased marrow
iron are likely to benefit from iron therapy.
Reference Values
Normal Bone marrow: 33% sideroblasts present Peripheral blood: no siderocytes present
Procedure
1. Make bone marrow slides (bone marrow biopsy material can be used), stain, and examine under the microscope for
the presence of iron.
2. Remember that this test may also be done on peripheral blood for the detection of sidero-blastic anemias.
Clinical Implications
1. Bone marrow iron is decreased in:
a. Iron deficiency from all causes of chronic bleeding, hemorrhage, malignancy
b. Polycythemia vera
c. Pernicious anemia (early phase of therapy)
d. Collagen diseases (eg, rheumatoid arthritis, SLE)
e. Infiltration of marrow by malignant lymphomas, carcinoma
f. Chronic infection
g. Myeloproliferative diseases
h. Uremia
2. Bone marrow iron is increased in:
a. Hemochromatosis (primary and secondary)
b. Anemia, especially thalassemia major and minor, PHN, and other hemolytic anemias
c. Megaloblastic anemia in relapse
d. Chronic infections
e. Chronic pancreatic insufficiency
Interfering Factors Ingestion of iron dextran will bring values to normal despite other evidence of iron-deficiency anemia.
Interventions
Pretest Patient Care
1. See preparation guidelines for bone marrow aspiration (see page 45).
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. See aftercare guidelines for bone marrow aspiration (see page 46).
2. See Chapter 1 guidelines for safe, effective, informed posttest care .

TESTS FOR HEMOGLOBIN DISORDERS
Hemoglobin Electrophoresis
Normal and abnormal Hb can be detected by electrophoresis, which matches hemolyzed RBC material against standard
bands for the various Hb types known. The most common forms of normal adult Hb are Hb A 1, Hb A 2, and Hb F (fetal
Hb). Of the various types of abnormal Hb (hemoglobinopathies), the best known are Hb S (responsible for sickle cell
anemia) and Hb C (results in a mild hemolytic anemia). The most common abnormality is a significant increase in Hb A 2,
which is diagnostic of the thalassemias, especially ß-thalassemia trait. More than 350 variants of Hb have been
recognized and identified.

Clinical Alert
The results may be questionable if a blood transfusion has been given in the months preceding testing.
Reference Values
Normal Hb A 1: 96.5%–98.5% or 0.96–0.985 mass fraction Hb A 2 : 1.5%–3.5% or 0.015–0.035 mass fraction Hb F:
0%–1% or 0–0.01 mass fraction
Fetal Hemoglobin (Hemoglobin F; Alkali-Resistant Hemoglobin)
Hb F is a normal Hb manufactured in the RBCs of the fetus and infant; it makes up 50% to 90% of the Hb in the newborn.
The remaining portion of the Hb in the newborn is made up of Hb A 1 and Hb A 2, the adult types.

Under normal conditions, the manufacture of Hb F is replaced by the manufacture of adult Hb types during the first year
of life. But if Hb F persists and constitutes more than 5% of the Hb after 6 months of age, an abnormality should be
expected.
Determination of Hb F is used to evaluate thalassemia (an inherited abnormality in the manufacture of Hb), hemolytic
anemias, hereditary persistence of fetal Hb, and other hemoglobinopathies.
Reference Values
Normal Adults: 0%–2% or 0–0.02 mass fraction Hb F Newborns: 60%–90% or 0.60–0.90 mass fraction Hb F By 6
months of age: 2% or 0.02 mass fraction Hb F
Procedure
1. Use a 5-mL venous blood EDTA-anticoagulated sample for Hb electrophoresis.
2. Remember that a blood smear stain may also be done to identify cells containing Hb F (Kleihauer-Betke stain).
Clinical Implications Increased Hb F is found in:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.

Thalassemias (major and minor)
Hereditary familial fetal hemoglobinemia (persistence of Hb F)
Hyperthyroidism
Sickle cell disease
Hb H disease
Anemia, as a compensatory mechanism (pernicious anemia, PNH, sideroblastic anemia)
Leakage of fetal blood into the maternal bloodstream
Aplastic anemia (acquired)
Juvenile myeloid leukemia with absence of Philadelphia chromosome
Myeloproliferative disorders, multiple myeloma, lymphoma

Clinical Alert
In thalassemia minor, continued production of Hb F may occur on a minor scale (5%–10%), and the patient usually
lives. In thalassemia major, the values may reach 40%–90%. This continued production of Hb F leads to severe
anemia, and death usually ensues.
Interfering Factors
1. If analysis of the specimen is delayed for more than 2 to 3 hours, the level of Hb F may be falsely increased.
2. Infants small for gestational age or with chronic intrauterine anoxia have persistently elevated Hb F.
3. Hb F is increased during anticonvulsant drug therapy.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Ensure that the test is done before transfusion.
3. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome; counsel and monitor appropriately for thalassemia and anemia.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Hemoglobin A 2 (Hb A 2)
Hb A 2 levels have special application to the diagnosis of ß-thalassemia trait, which may be present even though the
peripheral blood smear is normal. The microcytosis and other morphologic changes of ß-thalassemia trait must be
differentiated from iron deficiency. Low MCV may be present in most patients with ß-thalassemia trait, but it does not
differentiate iron-deficient patients.
This measurement is used in the investigation of hemolytic anemias for hemoglobinopathies, especially thalassemia and
ß-thalassemia.
Reference Values
Normal Adult: 1.5%–3.5% or 0.015–0.035 mass fraction Newborns: 0%–1.8% or 0–0.018 mass fraction
Procedure
1. Draw a 5-mL venous sample of blood with EDTA anticoagulant.
2. Perform electrophoresis.
Clinical Implications
1. Increased Hb A 2 occurs in:

a. ß-Thalassemia major (3%–11%)
b. Thalassemia minor (3.5%–7.5%)
c. Thalassemia intermedia (6%–8%)
d. Hb A/S (sickle cell trait) (15%–45%)
e. Hb S/S (sickle cell disease) (2%–6%)
f. S-ß-thalassemia (3.0%–8.5%)
g. Megaloblastic anemia
h. Hyperthyroidism
i. Vitamin B 12 or folate deficiency
2. Decreased Hb A 2 occurs in:
a. Untreated iron-deficiency anemia
b. Sideroblastic anemia
c. Hb H disease
d. Erythroleukemia
Interfering Factors
1.
2.
3.
4.

Blood transfusions before electrophoresis will interfere with results.
High levels of Hb F usually are accompanied by low levels of A 2.
Hb C, Hb O, Hb E interfere with the electrophoric migration of A 2
If a patient with ß-thalassemia also has iron-deficiency anemia, the A 2 may be normal; therefore, retesting may be
needed after iron therapy.

Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Provide genetic counseling.
3. Follow Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome; counsel and monitor appropriately.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .
Hemoglobin S (Sickle Cell Test; Sickledex)
Sickle cell disease is a term for a group of hereditary blood disorders. Sickle cell anemia is caused by an abnormality of
Hb, the red protein in red blood cells that carries oxygen from the lungs to the tissues. People with sickle cell disease
make an abnormal Hb, hemoglobin S (Hb S). The red blood cells of a person with sickle cell disease do not last as long
as “normal” red blood cells. This result is chronic anemia. Also, these red blood cells lose their normal disk shape. They
become rigid and deformed and take on a “sickle” or crescent shape. These oddly shaped cells are not flexible enough to
squeeze through small blood vessels. This may result in blood vessels being blocked. The areas of the body served by
those blood vessels will then be deprived of their blood circulation, damaging tissues and organs. This homozygous state
of Hb S disease is associated with considerable morbidity and mortality. The heterozygous state presents little mortality.
This blood measurement is routinely done as a screening test for sickle cell anemia or trait and to confirm these
disorders. This test detects Hb S, an inherited, recessive gene. An examination is made of erythrocytes for the
sickle-shaped forms characteristic of sickle cell anemia or trait. This is done by removing oxygen from the erythrocyte. In
erythrocytes with normal Hb, the shape is retained, but erythrocytes containing Hb S assume a sickle shape. However,
the distinction between sickle cell trait and sickle cell disease is done by electrophoresis, which identifies an Hb pattern.
Reference Values
Normal Adult: None present
Procedure
1. Obtain a venous blood sample of 5 mL with EDTA. Place the specimen in a biohazard bag.
2. Perform the Sickledex test or Hb electrophoresis. Electrophoresis is more accurate and should be done in all
positive Sickledex screens.
Clinical Implications A positive test (Hb S present) means that great numbers of erythrocytes have assumed the typical
sickle cell (crescent) shape. Positive tests are 99% accurate.
1. Sickle cell trait
a. Definite confirmation of sickle cell trait by Hb electrophoresis reveals the following heterozygous (A/S) pattern:
Hb S, 20%–40%; HB A 1 , 60%–80%; Hb F, small amount. This means that the patient has inherited a normal Hb
gene from one parent and an Hb S gene from the other (heterozygous pattern). This patient does not have any
clinical manifestations of the disease, but some of the children of this patient may inherit the disease if the
patient's mate also has the recessive gene pattern.
b. The diagnosis of sickle cell trait does not affect longevity and is not accompanied by signs and symptoms of
sickle cell anemia. A/S occurs in 8.5% of African Americans.
c. Sickle cell trait can lead to renal papillary necrosis, hematuria, increased risk for pulmonary embolus, and
anterior segment ischemia.
2. Sickle cell anemia (Hb S disease)

a. Definite confirmation of sickle cell anemia by Hb electrophoresis reveals the following homozygous (S/S)
pattern: Hb S, 80%–100%; Hb F, most of the rest, Hb A 1, 0% (absent).
b. This means that an abnormal Hb S gene has been inherited from both parents (homozygous pattern). Such a
patient has all the clinical manifestations of the disease.
3. Hb C—Harlem (rare)
4. Hb C—Georgetown
5. Hb S in combination with other disorders, such as ß-thalassemia or Hb S-C
Interfering Factors
1. False-negative results occur in:
a. Infants younger than 3 months of age (maximum amounts reached by 6 months)
b. Coexisting thalassemias or iron deficiency
c. The solubility test is unreliable in pernicious anemia and polycythemia
2. False-positive results occur up to 4 months after transfusion with RBCs having sickle cell trait.
3. Hb D and Hb G migrate to same place as Hb F in electrophoresis.

Clinical Alert
A positive Sickledex test must be confirmed by electrophoresis.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Provide genetic counseling.
3. Follow Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome; counsel and monitor appropriately.
2. A positive diagnosis of sickle cell disorder has genetic implications, including the need for genetic counseling.
3. A person with sickle cell disease should avoid situations in which hypoxia may occur, such as very strenuous
exercise, traveling to high-altitude regions, or traveling in an unpressurized aircraft.
4. Because of the hypoxia created by general anesthetics and a state of shock, surgical and maternity patients with
sickle cell disease need very close observation.
5. See Chapter 1 guidelines for safe, effective, informed posttest care .
Methemoglobin (Hemoglobin M)
Methemoglobin is formed when the iron in the heme portion of deoxygenated Hb is oxidized to a ferric form rather than a
ferrous form. In the ferric form, oxygen and iron cannot combine. The formation of methemoglobin is a normal process
and is kept within bounds by the reduction of methemoglobin to Hb. Methemoglobin causes a shift to the left of the
oxyhemoglobin dissociation curve. When a high concentration of methemoglobin is produced in the RBCs, it reduces
their capacity to combine with oxygen; anoxia and cyanosis result.
This test is used to diagnose hereditary or acquired methemoglobinemia in patients with symptoms of anoxia or cyanosis
and no evidence of cardiovascular or pulmonary disease. Hb M is an inherited disorder of the Hb that produces cyanosis.
Methemoglobinemia is most commonly encountered as an acquired state as a result of medications such as phenacetin,
sulfonamides, or ingestion of nitrates.
Reference Values
Normal 0.4%–1.5% or 0.004–0.015 of total Hb A value of >40% or >0.40 is a critical value.
Procedure
1. Obtain a venous or arterial blood sample, anticoagulated with sodium fluoride.
2. Place on ice immediately and transport to laboratory in a biohazard bag. Methemoglobin is very unstable and must
be tested within 8 hours.
Clinical Implications
1. Hereditary methemoglobinemia (uncommon) is associated with:
a. A hemoglobinopathy, Hb M (40% [or 0.40] of the total Hb)
b. Deficiency of methemoglobin reductase (autosomal recessive)
c. Glutathione deficiency (dominant mode of transmission)
2. Acquired methemoglobinemia is associated with:
a. Black-water fever
b. Paroxysmal hemoglobinuria
c. Clostridial infection
3. Toxic effect of drugs or chemicals (most common cause):
a. Analgesics, phenacetin
b. Sulfonamide derivatives—sulfonamide S
c. Nitrates and nitrites; nitroglycerin

d.
e.
f.
g.
h.
i.

Antimalarials
Isoniazid
Quinones
Potassium chloride
Benzocaine, lidocaine
Dapsone (most common drug causing methemoglobinemia)

Clinical Alert
Critical (panic) values:
1. HbM of 30% (or 0.30) results in headaches, cyanosis
2. HbM of 70% (or 0.70) is usually fatal
Interfering Factors
1. Consumption of sausage, processed meats, or other foods rich in nitrites and nitrates
2. Absorption of silver nitrate used to treat extensive burns
3. Excessive intake of Bromo-Seltzer is a common cause of methemoglobinemia. (The patient appears cyanotic but
otherwise feels well.)
4. Smoking
5. Use of bismuth preparations for diarrhea (see Appendix J)
Interventions
Pretest Patient Care
1. Advise patient of purpose of test. Assess for history of Bromo-Seltzer or toxic drugs or chemicals.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome; counsel for cause of cyanosis and monitor appropriately for anoxia.
2. Be aware that treatment includes intravenous methylene blue and oral ascorbic acid.
3. Follow Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
Because fetal hemoglobin is more easily converted to methemoglobin than to adult hemoglobin, infants are more
susceptible than adults to methemoglobinemia, which may be caused by drinking well water containing nitrites.
Bismuth preparations for diarrhea may also be reduced to nitrites by bowel action.
Sulfhemoglobin
Sulfhemoglobin is an abnormal Hb pigment produced by the combination of inorganic sulfides with Hb.
Sulfhemoglobinemia manifests as a cyanosis. Sulfhemoglobinemia often accompanies drug-induced
methemoglobinemia.
This test is indicated in persons with cyanosis. Sulfhemoglobinemia may occur in association with the administration of
various drugs and toxins. The symptoms are few, but cyanosis is intense even though the concentration of
sulfhemoglobin seldom exceeds 10%.
Reference Values
Normal None present or 0%–1.0% or 0–0.01 of total Hb
Procedure
1. Draw a 5-mL venous blood sample, anticoagulated with EDTA or heparin.
2. Place the specimen in a biohazard bag. Sulfhemoglobin is stable.
Clinical Implications
1. Sulfhemoglobin is observed in patients who take oxidant drugs such as phenacetin, Bromo-Seltzer, sulfonamides,
and acetanilid. (See Appendix J.)
2. Sulfhemoglobin is formed rarely without exposure to drugs or toxins, as in chronic constipation and purging.
3. Sulfhemoglobin can be due to exposure to trinitrotoluene or zinc ethylene bisdithiocarbamate (fungicide).
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. Assess for exposure to drugs and toxins.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare

1. Interpret test outcome; counsel for cause of cyanosis and use of certain medications.
2. Sulfhemoglobinemia persists until the RBCs containing it are destroyed; therefore, the levels decline slowly over a
period of weeks. There is no treatment.
3. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Carboxyhemoglobin; Carbon Monoxide (CO)
Carboxyhemoglobin is formed when Hb is exposed to carbon monoxide (CO). The affinity of Hb for CO is 240 times
greater than for oxygen. CO poisoning causes anoxia because the carboxyhemoglobin formed does not permit Hb to
combine with oxygen.
This test is done to detect CO poisoning. Because carboxyhemoglobin is not capable of transporting oxygen, hypoxia
results, causing headache, nausea, vomiting, vertigo, collapse, or convulsions. Death may result from anoxia and
irreversible tissue changes. Carboxyhemoglobin produces a cherry-red or violet color of the blood and skin, but this may
not be present in chronic exposure. The most common causes of CO toxicity are automobile exhaust fumes, coal gas,
water gas, and smoke inhalation from fires. Smoking is a minor cause.
Reference Values
Normal Nonsmokers: <2.0% of total Hb or <0.02 fraction of Hb saturation Heavy smokers: 6.0%–8.0% or 0.06–0.08
fraction of Hb saturation Light smokers: 4.0%–5.0% or 0.04–0.05 fraction of Hb saturation Newborns: 10%–12% or
0.10–0.12 fraction of Hb saturation
Procedure
1. Draw a heparinized or EDTA venous blood sample of 5 mL heparin or EDTA and put on ice.
2. Keep sample tightly capped and transport to laboratory immediately in a biohazard bag.
Clinical Implications
1. Carboxyhemoglobin is increased in:
a. CO poisoning from many sources, including smoking, exhaust fumes, fires
b. Hemolytic disease
c. Blood in intestines
d. Newborns, because of fetal hemoglobin breakdown that yields endogenous CO
2. A direct correlation has been found between CO and symptoms of heart disease, angina, and myocardial infarction.
Interventions
Pretest Patient Care
1. Advise patient of purpose of test.
2. Draw blood sample before oxygen therapy has started.
3. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1.
2.
3.
4.

Interpret test outcome and counsel for cause of headache, dizziness, vomiting, convulsions, or coma.
Be aware that treatment consists of removal of the patient from the source of CO.
Initiate oxygen therapy either by supplemental oxygen at atmospheric pressure or by hyperbaric oxygen.
See Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
1.
2.
3.
4.
5.

With values of 10%–20% (0.10–0.20), the patient may be asymptomatic.
With 20%–30% (0.20–0.30), headache, nausea, vomiting, and loss of judgment occur.
With 30%–40% (0.30–0.40), tachycardia, hyperpnea, hypotension, and confusion occur.
With 50%–60% (0.50–0.60), there is loss of consciousness.
Values >60% (>0.60) cause convulsions, respiratory arrest, and death.

Myoglobin (Mb)
Myoglobin (Mb) is the oxygen-binding protein of striated muscle. It resembles Hb but is unable to release oxygen except
at extremely low tension. Injury to skeletal muscle results in release of myoglobin. It is not specific to myocardial muscle.
Myoglobin is not tightly bound to protein and is rapidly excreted in the urine.
The myoglobin test is used as an early marker of muscle damage in myocardial infarction and to detect injury damage or
necrosis to skeletal muscle. Serum myoglobin is found earlier than creatine kinase (CK) enzymes in acute myocardial
infarction.
Reference Values
Normal 5–70 ng/mL or 5–70 µg/L
Procedure
1. Draw a venous blood sample of at least 5 mL; use serum. Lipemic or grossly hemolyzed specimens are not

acceptable.
2. Remember that two or three samples taken 1–2 hours apart give optimal results in detecting myocardial infarction.
Clinical Implications
1. Increased myoglobin values are associated with:
a. Myocardial infarction (elevates 1 to 3 hours after pain onset, earlier than creatine kinase). Amount of myoglobin
correlates with size of infarct.
b. Angina without infarction
c. Other muscle injury (trauma, exercise, open heart surgery, intramuscular injections)
d. Polymyositis and progressive muscular dystrophy
e. Myositis
f. Rhabdomyolysis
g. Inflammatory myopathy (eg, SLE)
h. Toxin exposure: narcotics, Malayan sea snake toxin
i. Malignant hyperthermia
j. Renal failure
k. Electric shock
l. Tonic-clonic seizures
2. Decreased myoglobin values are found in:
a. Circulating antibodies to myoglobin (many patients with polymyositis)
b. Rheumatoid arthritis
c. Myasthenia gravis
Interfering Factors
1. See Appendix J for drugs that affect test outcomes.
2. Cocaine use elevates myoglobin.
3. Decreased elimination due to kidney insufficiency causes increase of serum levels.
Interventions
Pretest Patient Care
1.
2.
3.
4.

Advise patient of test purpose.
Have patient avoid radioisotopes until after blood is drawn.
Avoid vigorous exercise before the test because it may elevate myoglobin.
See Chapter 1 guidelines for safe, effective, informed pretest care.

Posttest Patient Aftercare
1. Resume normal activities.
2. Interpret test outcomes; counsel and monitor appropriately for myocardial infarction, muscle inflammation, and
metabolic stress.
3. See Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
Myoglobin is currently the earliest biologic marker of myocardial necrosis. It appears in the peripheral blood 2 to 3
hours after pain onset and reaches peak levels at 6 to 9 hours. Myoglobin is a sensitive indicator of acute myocardial
infarction but is not specific for cardiac muscle.
Haptoglobin (Hp)
Haptoglobin (Hp) is a transport glycoprotein synthesized solely in the liver. It is a carrier for free Hb in plasma; its primary
physiologic function is the preservation of iron. Haptoglobin binds Hb and carries it to the reticuloendothelial system.
A decrease in Hp (with normal liver function) is most likely to occur with increased consumption of Hp due to
intravascular hemolysis. The concentration of Hp is inversely related to the degree of hemolysis and to the duration of
hemolytic episode.
Reference Values
Normal Newborns: 5–48 mg/dL or 50–480 mg/L (may be absent at birth) Children: reach adult levels by 1 year Adults:
40–200 mg/dL or 0.4–2.0 g/L
Procedure
1. Obtain a venous blood sample of at least 2 mL. Place the specimen in a biohazard bag.
2. Measure the serum for Hp by a radial immunodiffusion method. A single determination is of limited value.
Clinical Implications
1. Hp is decreased in acquired disorders such as:
a. Intravascular hemolysis from any cause
b. Autoimmune hemolytic anemia

c. Other hemoglobinemias caused by intravascular hemorrhages, especially artificial heart valves, and acute
bacterial endocarditis
d. Transfusion reactions
e. Erythroblastosis fetalis
f. Malarial infestation
g. PNH
h. Hematoma, tissue hemorrhage
i. Thrombotic thrombocytopenic purpura
j. Drug-induced hemolytic anemia (methyldopa)
k. Acute or chronic liver disease
2. Hp is decreased in some inherited disorders, such as:
a. Sickle cell disease
b. G6PD and pyruvate kinase deficiency
c. Hereditary spherocytosis
d. Thalassemia and megaloblastic anemias
e. Congenital absence is observed in 1% of black and Asian populations
3. Hp is increased in:
a. Infection and inflammation (acute or chronic)
b. Neoplasias, lymphomas (advanced)
c. Biliary obstruction
d. Acute rheumatic disease and other collagen diseases
e. Tissue destruction
Interfering Factors
1.
2.
3.
4.

Estrogen and oral contraceptives lower Hp.
Steroid therapy raises Hp.
Androgens increase Hp.
Regular strenuous exercise lowers Hp.

Clinical Alert
Normal Hp results measured during inflammatory episodes or during steroid treatment do not rule out hemolysis.
Interventions
Pretest Patient Care
1.
2.
3.
4.

Advise patient of test purpose.
Avoid use of oral contraceptives and androgens before blood is drawn. (Check with physician.)
Avoid exercise before test.
Follow Chapter 1 guidelines for safe, effective, informed pretest care.

Posttest Patient Aftercare
1. Resume normal activities and medications.
2. Interpret test results. Repeat testing may be necessary. Monitor appropriately for abnormal bleeding.
3. See Chapter 1 guidelines for safe, effective, informed posttest care .
Bart's Hemoglobin
Bart's Hb is an unstable Hb with high oxygen affinity. When there is complete absence of production of the chain of Hb
and deletion of all four globin genes, the disorder is known as Bart's hydrops fetalis. Both parents of the affected infant
have heterozygous thalassemia; they are almost all Southeast Asians. Affected infants are either stillborn or die shortly
after birth.
This test determines the percentage of the abnormal Bart's Hb in cord blood and identifies a-thalassemia
hemoglobinopathies.
Reference Values
Normal Adults: None Children: None Newborns: <0.5% or <0.005 mass fraction of total Hb
Procedure
1. Obtain a sample of cord blood, and perform Hb electrophoresis.
2. Be aware that venous blood anticoagulated with EDTA or heparin can be used.
Clinical Implications Increased levels are associated with:
1. Homozygous a-thalassemia (hydrops fetalis syndrome, which causes stillbirth)
2. Hb H disease
3. a-Thalassemia minor
Interventions
Pretest Patient Care

1. Explain test purpose and procedure to parents.
2. Be aware that obstetric complications may lead to significant morbidity and mortality for the mothers of these
infants.
3. Provide genetic counseling in a sensitive manner.
4. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome and counsel parents.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .
Paroxysmal Nocturnal Hemoglobinuria (PNH) Test; Acid Hemolysis Test; Ham's Test
PNH was first described by a patient who noted hemoglobinuria after sleep. In many patients, the hemolysis is irregular
or occult. PNH is a hemolytic anemia in which there is also production of defective platelets and granulocytes. The
diagnostic feature of PNH is an increased sensitivity of the erythrocytes to complement-mediated lysis. Although patients
with PNH can present with hemoglobinuria or a hemolytic anemia, they may also present with iron deficiency (because of
urinary loss of blood), bleeding secondary to thrombocytopenia, thrombosis, renal abnormalities, or neurologic
abnormalities.
These tests are carried out to make a definitive diagnosis of PNH. The basis of these tests is that the cells peculiar to
PNH have membrane defects, making them extrasensitive to complement in the plasma. Cells from patients with PNH
undergo marked hemolysis after 15 minutes in the laboratory test. The tests are performed for patients who have
hemoglobinuria, bone marrow aplasia (hypoplasia), or undiagnosed hemolytic anemia; they may be useful in the
evaluation of patients with unexplained thrombosis or acute leukemia.
Reference Values
Normal Negative or <1% hemolysis
Procedure
1. Obtain a venous blood sample of 5 mL anticoagulated with EDTA. Place the specimen in a biohazard bag.
2. Mix the patient's RBCs with normal serum and also with the patient's own serum, acidify, incubate at 37°C, and
examine for hemolysis. Normally, there should be no lysis of the RBCs in this test (also called Ham's test).
3. Be aware that a separate test called the sugar water test or sucrose hemolysis test may also be done at this time.
Clinical Implications A positive test (hemolysis) is found in:
1. PNH: a positive test (10%–50% lysis) is needed for diagnosis. The sucrose hemolysis test is also positive in PNH.
2. Hereditary erythroblastic multinuclearity associated with a positive acidified serum test (HEMPAS): the sucrose
hemolysis test is negative.
Interfering Factors
1. False-positive results may be obtained with the following:
a. Blood containing large numbers of spherocytes (hereditary or acquired)
b. Dyserythropoietic anemia
c. Specimen >8 hours old, specimen hemolyzed
d. Aplastic anemia
e. Leukemia and myeloproliferative syndromes
2. These conditions can be distinguished from PNH by the fact that hemolysis occurs in both acidified serum and
complement. In PNH, hemolysis occurs only in complement (complement dependent).
Interventions
Pretest Patient Care
1. Explain test purpose.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test results; counsel and monitor appropriately for anemia.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .

OTHER BLOOD TESTS FOR ANEMIA
Vitamin B 12 (VB 12)
Vitamin B 12 (VB 12), also known as the antipernicious anemia factor, is necessary for the production of RBCs. It is
obtained only from ingestion of animal protein and requires an intrinsic factor for absorption. Both VB 12 and folic acid
depend on a normally functioning intestinal mucosa for their absorption and are important for the production of red blood
cells. Levels of VB 12 and folate are usually tested in conjunction with one another because the diagnosis of macrocytic

anemia requires measurement of both.
This determination is used in the differential diagnosis of anemia and conditions marked by high turnover of myeloid
cells, as in the leukemias. When binding capacity is measured, it is the unsaturated fraction that is determined. The
measurement of unsaturated VB 12-binding capacity (UBBC) is valuable in distinguishing between untreated
polycythemia vera and other conditions in which there is an elevated Hct.
Reference Values
Normal Adults: 200–835 pg/mL or 148–616 pmol/L Newborns: 160–1300 pg/mL or 118–959 pmol/L UBBC: 600–1400
pg/mL or 443–1033 pmol/L
Procedure
1. Obtain a fasting venous blood sample of at least 5 mL.
2. Obtain the specimen before an injection of VB 12 is administered and before a Schilling test is done. Place the
specimen in a biohazard bag.
Clinical Implications
1. Decreased VB 12 (<100 pg/mL or <74 pmol/L) is associated with:
a. Pernicious anemia (megaloblastic anemia)
b. Malabsorption syndromes and inflammatory bowel disease
c. Fish tapeworm infestation
d. Primary hypothyroidism
e. Loss of gastric mucosa, as in gastrectomy and resection
f. Zollinger-Ellison syndrome
g. Blind loop syndromes (bacterial overgrowth)
h. Vegetarian diets (dietary insufficiency)
i. Folic acid deficiency
j. Iron deficiency may be present in some patients (eg, gastrectomy)
2. Increased VB 12 (>700 pg/mL or >517 pmol/L) is associated with:
a. Chronic granulocytic leukemia, lymphatic and monocytic leukemia
b. Chronic renal failure
c. Liver disease (hepatitis, cirrhosis)
d. Some cases of cancer, especially with liver metastasis
e. Polycythemia vera
f. Congestive heart failure
g. Diabetes
h. Obesity
i. COPD
3. Increased UBBC is found in:
a. Sixty percent of cases of polycythemia vera. (This test is normal in secondary relative polycythemia, aiding in
the differential diagnosis of these two states.)
b. Reactive leukocytosis (leukemoid reaction)
c. Chronic myelogenous leukemia
Interfering Factors The following result in increased VB 12 values:
1.
2.
3.
4.
5.
6.

Pregnancy
Blood transfusion
Aged persons
High vitamin C and A doses
Smoking
Drugs capable of interfering with VB 12 absorption (see Appendix J)

Interventions
Pretest Patient Care
1.
2.
3.
4.

Explain test purpose and procedure.
Alert patient that overnight fasting from food is necessary. Water is permitted.
Withhold VB 12 injection before the blood is drawn.
Follow Chapter 1 guidelines for safe, effective, informed pretest care.

Posttest Patient Aftercare
1. Resume normal activities and diet.
2. Interpret test results; counsel and monitor appropriately for anemia, leukemia, or polycythemia.
3. See Chapter 1 guidelines for safe, effective, informed posttest care . See Appendix F for more information on
vitamin testing.

Clinical Alert
1. Persons who have recently received therapeutic or diagnostic doses of radionuclides will have unreliable results.
2. See Appendix F for more information on nutritional status of vitamin B 12.

Clinical Alert
The Schilling test is used to confirm pernicious anemia and to determine whether vitamin B 12 deficiency is caused by
malabsorption.
Folic Acid (Folate)
Folic acid is needed for normal RBC and WBC function and for the production of cellular genes. Folic acid is a more
potent growth promoter than VB 12, although both depend on the normal functioning of intestinal mucosa for their
absorption. Folic acid, like VB 12, is required for DNA production. Folic acid is formed by bacteria in the intestines, is
stored in the liver, and is present in eggs, milk, leafy vegetables, yeast, liver, fruits, and other elements of a
well-balanced diet.
This test is indicated for the differential diagnosis of megaloblastic anemia and in the investigation of folic acid deficiency,
iron deficiency, and hypersegmental granulocytes. Measurement of both serum and RBC folate levels constitutes a
reliable means of determining the existence of folate deficiency. The finding of low serum folate means that the patient's
recent diet was subnormal in folate content, that the patient's recent absorption of folate was subnormal, or both. Low
RBC folate can mean either that there is tissue folate depletion owing to folate deficiency requiring folate therapy or,
alternatively, that the patient has primary VB 12 deficiency that is blocking the ability of cells to take up folate. Serum
levels are commonly high in patients with VB 12 deficiency because this vitamin is needed to allow incorporation of folate
into tissue cells. For thoroughness, the serum VB 12 should also be determined, because more than 50% of all patients
with significant megaloblastic anemia have VB 12 deficiency rather than folate deficiency.
Reference Values
Normal Adults: 2–20 ng/mL (serum) or 4.5–45.3 nmol/L Children: 5–21 ng/mL (serum) or 11.3–47.6 nmol/L Infants:
14–51 ng/mL or 31.7–115.5 nmol/L Red blood cell folate: Adults: 140–628 ng/mL or 317–1422 nmol/L Children: >160
ng/mL or >362 nmol/L
Procedure
1. Obtain a fasting venous sample of 10 mL. Protect the sample from light. Place the specimen in a biohazard bag.
2. If RBC folate is ordered, draw 5 mL of venous blood with EDTA anticoagulant. An Hct determination is also
required.
Clinical Implications
1. Decreased folic acid levels are associated with:
a. Inadequate intake owing to alcoholism, chronic disease, malnutrition, diet devoid of fresh vegetables, or
anorexia
b. Malabsorption of folic acid (eg, small bowel disease)
c. Excessive use of folic acid by the body (eg, pregnancy, hypothyroidism)
d. Megaloblastic (macrocytic) anemia caused by VB 12 deficiency
e. Hemolytic anemia (sickle cell, phenocytosis, PNH)
f. Liver disease associated with cirrhosis, alcoholism, hepatoma
g. Adult celiac disease, sprue
h. Vitamin B 6 deficiency
i. Carcinomas (mainly metastatic), acute leukemia, myelofibrosis
j. Crohn's disease, ulcerative colitis
k. Infantile hyperthyroidism
l. Intestinal resection, jejunal bypass procedure
m. Drugs that are folic antagonists (interfere with nucleic acid synthesis):
1. Anticonvulsants (phenytoin)
2. Aminopterin and methotrexate
3. Antimalarials
4. Alcohol (ethanol)
5. Oral contraceptives
6. Heavy usage of antacids
2. Increased folic acid levels are associated with:
a. Blind loop syndrome
b. Vegetarian diet
c. Pernicious anemia, VB 12 deficiency
3. Decreased RBC folate occurs with:
a. Untreated folate deficiency
b. VB 12 deficiency (60% of uncomplicated cases)
Interfering Factors
1. Drugs that are folic acid antagonists, among others (see Appendix J)
2. Hemolyzed specimens (false elevation)
3. Iron-deficiency anemia (false increase)

Clinical Alert
Elderly persons and those with inadequate diets may develop folate-deficient megaloblastic anemia.
Interventions
Pretest Patient Care
1.
2.
3.
4.
5.

Explain test purpose and procedure. Obtain pertinent medication history.
Alert patient that fasting from food for 8 hours before testing is required; water is permitted.
Draw blood before VB 12 injection.
Do not administer radioisotopes for 24 hours before the specimen is drawn.
See Chapter 1 guidelines for safe, effective, informed pretest care.

Posttest Patient Aftercare
1. Resume normal activities and medications.
2. Interpret test results; counsel and monitor appropriately for anemia.
3. See Chapter 1 guidelines for safe, effective, informed posttest care . See Appendix F for more information on
vitamin testing.
Erythropoietin (Ep)
Erythropoietin (Ep) is a glycoprotein hormone that regulates erythropoiesis. The levels of Ep in anemia are primarily
determined by the degree of anemia; Ep is inversely related to red blood cell volume and Hct.
Ep is used to investigate obscure anemias. This test is useful in differentiating primary from secondary polycythemia and
in detecting the recurrence of Ep-producing tumors. It is also used as an indicator of need for Ep therapy in patients with
renal failure (end-stage renal disease).
Reference Values
Normal 5–36 mU/mL or 5–36 U/L
Procedure
1. Obtain a venous blood serum sample of 5 mL. Place the specimen in biohazard bag.
2. Separate serum from cells as soon as possible and place in polypropylene tube ( not clear plastic-polystyrene).
Freeze.
Clinical Implications
1. Ep is increased appropriately in:
a. Anemias with very low Hb (eg, aplastic anemia, hemolytic anemia); hematologic cancers have very high levels.
b. Patients with any iron-deficiency anemia have moderately high levels.
c. Myelodysplasia, chemotherapy, AIDS
d. Secondary polycythemia vera caused by tissue hypoxia (eg, high altitude, COPD)
e. Pregnancy (very high values)
2. Ep is increased inappropriately in erythropoietin-producing tumors:
a. Renal cysts, renal transplant rejection
b. Renal adenocarcinoma
c. Pheochromocytomas
d. Cerebellar hemangioblastomas
e. Polycystic kidney disease
f. Occasionally, adrenal, ovarian, testicular, breast, and hepatic carcinoma
3. Ep is decreased appropriately in:
a. Rheumatoid arthritis
b. Multiple myeloma
c. Cancer
4. Ep is decreased inappropriately in:
a. Polycythemia vera (primary)
b. After bone marrow transplantation (weeks 3 and 4)
c. AIDS before initiating therapy
d. Autonomic neuropathy
e. Renal failure and adult nephrotic syndrome
Interfering Factors
1. Ep is increased in:
a. Pregnancy
b. Use of anabolic steroids
c. Administration of thyroid-stimulating hormone, ACTH, epinephrine
d. Growth hormone (see Appendix J)
2. Ep is decreased in:
a. Transfusions
b. Use of some prescribed drugs (see Appendix J)
c. Drugs that increase renal blood flow (eg, enalapril)

d. High plasma viscosity
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Draw blood at the same time for serial determinations: Circadian rhythm is lowest in the morning and 40% higher in
late evening.
3. Alert patient that fasting is not necessary, but a morning specimen is needed.
4. Note use of any drugs.
5. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Resume normal activities and medications.
2. Interpret test results; counsel and monitor appropriately for anemia.
3. See Chapter 1 guidelines for safe, effective, informed posttest care . See Appendix F for more information on
vitamin testing.

TESTS OF HEMOSTASIS AND COAGULATION
The prime functions of the coagulation mechanism are to protect the integrity of the blood vessels while maintaining the
fluid state of blood. Serious medical problems or even death may occur with the inability to stem the loss of blood, or for
the inability for a normal clot to form.
Hemostasis and coagulation tests are generally done for patients with bleeding disorders, vascular injury or trauma, or
coagulopathies. Reflex vasoconstriction is the normal response to vascular insult once the first-line defenses (skin and
tissue) are breached. In larger vessels, vasoconstriction may be the primary mechanism for hemostasis. With smaller
vessels, vasoconstriction reduces the size of the area that must be occluded by the hemostatic plug. Part of this cascade
of sequential clotting events relates to the fact that platelets adhere to the injured and exposed subendothelial tissues.
This phenomenon initiates the complex clotting mechanism whereby thrombin and fibrin are formed and deposited to aid
in intravascular clotting ( Table 2.4).

Table 2.4 The Complex Chain of Coagulation Reactions
A balance normally exists between the factors that stimulate formation of thrombin and forces acting to delay thrombin
formation. This balance maintains circulating blood as a fluid. When injury occurs or blood is removed from a vessel, this
balance is upset and coagulation occurs. Blood clotting involves four progressive stages. The Roman numerals assigned
to the coagulation factors identify their order of discovery rather than their involvement in the stages of clot formation.
Stage
Components of Stages
STAGE I (3–5 MIN)
Phase I—platelet activity; platelets serve as a source of
thromboplastin.
Phase II—thromboplastin; factor III, an enzyme thought to be
liberated by damaged cells, is formed by six different factors
plus calcium.

90% of all coagulation disorders are caused by defects
in phase I. Platelet counts <1 × 10 6/mm 3 indicate
moderate interference with phase I activity.
Calcium
are involved in the formation of tissue
Factor V
thromboplastin (intrinsic prothrombin
Factor
activation)
VIII
Factor
IX
Factor X
Factor
XI
Factor
XII

STAGE II (8–15 SEC)
Prothrombin factor II is converted to thrombin in the presence of Factor II
calcium.
Factor X
Factor
VII
Factor V

STAGE III (1 SEC)
Thrombin interacts with fibrinogen (factor I) to form the
framework of the clot.
STAGE IV

are involved in the conversion of
fibrinogen to fibrin

At the end stage III, factor XIII functions in the
stabilization of the clot.

Fibrinolytic system (antagonistic check-and-balance to the
clotting mechanism) is activated.

Removal of fibrin clot through fibrinolysis. Plasminogen
is converted to plasmin, which breaks clot into fibrin split
products.

The entire mechanism of coagulation and fibrinolysis (removal of fibrin clot) is one of balance. It may best be understood
by referring to the diagrams in this section. Abnormal bleeding does not always indicate coagulopathy, in much the same
way that lack of bleeding does not necessarily indicate absence of a bleeding disorder.
The most common causes of hemorrhage are thrombocytopenia (platelet deficiency) and other acquired coagulation
disorders, including liver disease, uremia, disseminated intravascular coagulation (DIC), and anticoagulant
administration. Together, they account for most hemorrhagic problems. Hemophilia and other inherited factor deficiencies
are seen less frequently. Bleeding tendencies are associated with delays in clot formation or premature clot lysis.
Thrombosis is associated with inappropriate clot activation or localization of the blood coagulation process. Finally,
clotting disorders are divided into two classes: those caused by impaired coagulation and those caused by
hypercoagulability.
Hypercoagulability States
Two general forms of hypercoagulability exist: hyperreactivity of the platelet system, which results in arterial thrombosis,
and accelerated activity of the clotting system, which results in venous thrombosis. Hypercoagulability refers to an
unnatural tendency toward thrombosis. The thrombus is the actual insoluble mass (fibrin or platelets) present in the
bloodstream or chambers of the heart.
Conditions and classifications associated with hypercoagulability include the following:
Platelet Abnormalities. These conditions are associated with arteriosclerosis, diabetes mellitus, increased blood lipids
or cholesterol levels, increased platelet levels, and smoking. Arterial thrombosis may be related to blood flow
disturbances, vessel wall changes, and increased platelet sensitivity to factors causing platelet adherence and
aggregation.
Clotting System Abnormalities. These are associated with congestive heart failure, immobility, artificial surfaces (eg,
artificial heart valves), damaged vasculature, use of oral contraceptives or estrogen, pregnancy and the postpartum
state, and the postsurgical state. Other influences include malignancy, myeloproliferative (bone marrow) disorders,
obesity, lupus disorders, and genetic predisposition.
Venous Thrombosis. This can be related to stasis of blood flow, to coagulation alterations, or to increases in
procoagulation factors or decreases in anticoagulation factors ( Table 2.5).

Table 2.5 Proteins Involved in Blood Coagulation
Protein *

Synonym

Plasma
Concentration
(mg/dL)

Function

Fibrinogen

Factor I

200–400

Factor II

Prothrombin (prethrombin)

10–15

Factor V
Factor VII
Factor VIII:C

Proaccelerin; labile factor
Stable factor; proconvertin
Antihemophilic factor (AHF)
platelet cofactor I
Christmas factor; plasma
thromboplastin component (PTC)
Stuart-Prower factor (AVTD
prothrombin III)
Plasma thromboplastin
antecedent (antihemophilic factor
C)
Hageman factor
Fibrin-stabilizing factor;
Laki-Lorand factor
Factor VIII–related antigen
VIII:VWD
Fletcher factor

0.5–1.0
0.2
1.0–2.0

Converted to fibrin along with
platelets to form clot
Is converted to thrombin (IIa),
which splits fibrinogen into fibrin
Supports Xa activation of II to IIa
Activates X
Supports IXa activation of X

0.3–0.4

Activates X

0.6–0.8

Activates II

0.4

Activates XII and prekallikrein

2.9
2.5

Fitzgerald factor

4.7–12.2

Cold insoluble globulin

20–40

Activates XI and prekallikrein
Crosslinks fibrin and other
proteins
Stabilizes VIII, mediates platelet
adhesion
Activates XII and prekallikrein,
cleaves HMWK
Supports reciprocal activation of
XII, XI and prekallikrein
Mediates cell adhesion

Factor IX
Factor X
Factor XI

Factor XII
Factor XIII
von Willebrand's factor
Prekallikrein
High-molecular-weight
kininogen (HMWK)
Fibronectin

1.0
5.0

Major antithrombin

Antithrombin III

20–40

Protein C

0.5

Plasminogen

20

a 2-Antiplasmin
a 1-Antitrypsin

9.6–13.5
245–335

Inhibits IIa, Xa, XIa, XIIa, and
kallikrein
Complexed with protein S,
inactivates V and VIII
Forms plasmin, which lyses the
fibrin clot and inhibits other
factors
Inhibits plasmin
Weak inhibitor of thrombin,
potent inhibitor of XIa
Activates plasminogen
Inactivates tissue plasminogen
activator (tPA)
Inactivates urokinase

Tissue plasminogen
Plasminogen activator
inhibitor I
Plasminogen activator
inhibitor II
*The clotting factors of the blood are proteins; they are present in the blood plasma in an inactive form called zymogens.

Disorders of Hemostasis
Congenital Vascular Abnormalities (Vessel Wall Structure Defects). Defects of the actual blood vessel are poorly
defined and difficult to test. Hereditary telangiectasia is the most commonly recognized vascular abnormality. Laboratory
studies are normal, so the diagnosis must be made from clinical signs and symptoms. Patients frequently report epistaxis
and symptoms of anemia. Another abnormality is congenital hemangiomas (Kasabach-Merritt syndrome).
Acquired Abnormalities of the Vessel Wall Structure. Causes include Henoch-Schönlein purpura as an allergic
response to infection or drugs, diabetes mellitus, rickettsial diseases, septicemia, and amyloidosis present with some
degree of vascular abnormalities. Purpura can also be associated with steroid therapy and easy bruising in females
(infectious purpura), or it can be a result of drug use.
Hereditary Connective Tissue Disorders. These include Ehlers-Danlos syndrome (hyperplastic skin and hyperflexible
joints) and pseudoxanthoma elasticum (rare connective tissue disorder).
Acquired Connective Tissue Defects. These can be caused by scurvy (vitamin C deficiency) or senile purpura.
Qualitative Platelet Abnormalities. These disorders can be divided into subclasses:
1. Thrombocytopenia (platelet count <150 × 10 3 /mm 3) is caused by decreased production of platelets, increased use
or destruction of platelets, or hypersplenism. Contributing factors include bone marrow disease, autoimmune
diseases, DIC, bacterial or viral infection, chemotherapy, therapy radiation, multiple transfusions, and certain drugs
(eg, NSAIDs thiazides, estrogens).
2. Thrombocytosis (elevated platelet count) is caused by hemorrhage, iron-deficiency anemia, inflammation, or
splenectomy.
3. Thrombocythemia (platelet count >1000 × 10 3/mm 3 or >1000 × 10 9/L) is caused by granulocytic leukemia,
polycythemia vera, or myeloid metaplasia.

Clinical Alert
An increased platelet count predisposes the patient to arterial thrombosis. Paradoxically, a substantially elevated
platelet count can also cause easy bleeding after dental surgery, gastrointestinal bleeding, and epistaxis.

Clinical Alert
When the platelet count is substantially decreased, bleeding can occur in the nose, gastrointestinal tract, skin, and
gums.
Quantitative Platelet Abnormalities. These are associated with Glanzmann's thrombasthenia, a hereditary
autosomal-recessive disorder that can produce severe bleeding, especially with trauma and surgical procedures. Platelet
factor 3 differences associated with aggregation, adhesion, or release defects may be manifested in storage-pool
disease, May-Hegglin anomaly, Bernard-Soulier syndrome, and Wiskott-Aldrich syndrome. Dialysis and use of drugs
such as aspirin, other antiinflammatory agents, dipyridamole, and prostaglandin E also can be tied to platelet
abnormalities.
Congenital Coagulation Abnormalities. These include hemophilia A and B (deficiencies of factors VIII and IX,
respectively), rare autosomal recessive traits (hemophilia C), and autosomal dominant traits (eg, von Willebrand's
disease).
Acquired Coagulation Abnormalities. These are associated with several disease states and are much more common
than inherited deficiencies.
1. Circulatory anticoagulant activity may be evident in the presence of antifactor VIII, rheumatoid arthritis, immediate

2.
3.
4.

5.

postpartum period, SLE, or multiple myeloma.
Vitamin D deficiency may be caused by oral anticoagulants, biliary obstruction and malabsorption syndrome, or
intestinal sterilization by antibiotic therapy. Newborns are prone to vitamin D deficiency.
DIC causes continuous production of thrombin, which, in turn, consumes the other clotting factors and results in
uncontrolled bleeding.
Primary fibrinolysis is the situation whereby isolated activation of the fibrinolytic mechanism occurs without prior
coagulation activity, as in streptokinase therapy, severe liver disease, prostate cancer, or, more rarely,
electroshock.
Most coagulation factors are manufactured in liver. Consequently, in liver disease, the extent of coagulation
abnormalities is directly proportional to the severity of the liver disease.

Tests for Disseminated Intravascular Coagulation (DIC)
DIC is an acquired hemorrhagic syndrome characterized by uncontrolled formation and deposition of fibrin thrombi.
Continuous generation of thrombin causes depletion (consumption) of the coagulation factors and results in uncontrolled
bleeding. Also, fibrinolysis is activated in DIC. This further adds to the hemostasis defect caused by the consumption of
clotting factors. The many coagulation test abnormalities found in acute DIC include the following:
1. Prolonged
a. Prothrombin time (PT)
b. Partial thromboplastin time (PTT) or activated partial thromboplastin time (APTT)
c. Bleeding time
d. Thrombin time (TT)
2. Decreased
a. Fibrinogen
b. Platelet count
c. Clotting factors II, V, VIII, and X
d. Antithrombin III (AT-III)
3. Increased
a. Fibrinolysin test
b. Fibrinopeptide A
4. Positive
a. Fibrin split products
b. D-Dimer
In chronic DIC, the results are variable, especially the PT, PTT, TT, and fibrinogen, making the diagnosis much more
difficult. No single test or group of tests is diagnostic, and diagnosis usually depends on a combination of findings.
Normal levels do not rule out DIC, and a repeat profile should be done a few hours later to look for changes in platelet
count and fibrinogen.
Causes of DIC include septicemia, malignancies and cancer, obstetric emergencies, cirrhosis of liver, sickle cell disease,
trauma or crushing injuries, malaria, incompatible blood transfusion, cold hemoglobinuria or PNH, connective tissue
diseases, snake bites, and brown recluse spider bites.
Paradoxically, the treatment of uncontrolled bleeding in DIC is heparin administration. The heparin blocks thrombin
formation, which blocks consumption of the other clotting factors and allows hemostasis to occur.
Laboratory Investigation of Hemostasis Usually, a blood sample of at least 20 mL is obtained by the two-tube
technique. In the first tube, a 5-mL blood sample is obtained and discarded. Then 15 to 20 mL of blood is drawn into
Vacutainer tubes with sodium citrate as the anticoagulant. A butterfly needle may be used to prevent backflow or to make
sampling easier in the case of a difficult draw. Coagulation studies ( coagulation profiles, coag panels, coagulograms ) are
used for screening or as diagnostic tools for evaluation of symptoms such as easy or spontaneous bruising, petechiae,
prolonged bleeding (eg, from cuts), abnormal nosebleeds, heavy menstrual flow, family history of coagulopathies, or
gastrointestinal bleeding ( Table 2.6).
Table 2.6 Laboratory Tests to Measure Hemostasis *
Name of Test

Vascular Function Platelet Function Stage I Stage II Stage III Stage IV

Bleeding time
X
Platelet count
Platelet adhesiveness
Platelet aggregation
Aspirin tolerance
X
Platelet factor III assay
Activated clotting
X
Activated recalcification time
Activated partial thromboplastin
Prothrombin time
Stypven ** time
Circulating anticoagulant factor I.D. substitution
Factor assay
Thrombin time
Reptilase time

X
X
X
X
X
X

X
X
X
X
X
X

X
X
X
X
X
X
X
X

X
X
X

X

Fibrinogen assay
Factor XIII assay
X
Euglobulin lysis time
Thrombin time—diluted
X
Plasminogen assay
Protamine sulfate (ethanal gelation)
D-Dimer
Fibrin monomer
Fibrinopeptide A
Latex agglutination for fibrin split products
*These tests measure all facets of hemostasis: vascular function, platelets, and clotting factors.
**Activates factor X.

X
X
X
X
X

X
X
X

X
X

Many of the more common screening tests are now automated and easily done. Platelet counts are included in the
automated CBC with most instruments protime, and PTT can be done on photooptical instruments that sense the change
in optical density when a clot forms. Tests for fibrinogen are on instruments that detect fibrin strands. Many patients can
undergo testing at the same time with the help of automation. Some of the more specialized tests still must be done
manually or using semiautomated methods.
1. These five primary screening tests are initially performed to diagnose suspected coagulation disorders:
a. Platelet count, size, and shape
b. Bleeding time—reflects data about the ability of platelets to function normally and the ability of the capillaries to
constrict their walls
c. PTT—determines the overall ability of the blood to clot
d. PT—measures the function of second-stage clotting factors
e. Fibrinogen level
2. Factor assays are definitive coagulation studies of a specific clotting factor (eg, factor VIII for hemophilia). These
are done if the screening test indicates a problem with a specific factor or factors.
3. Fibrinolysis is used to address problems of the fibrinolytic system and includes the following studies:
a. Euglobulin clot lysis—identifies increased plasminogen activator activity. (Plasmin is not usually present in the
blood plasma.)
b. Factor XIII (fibrin-stabilizing factor)
c. Fibrin split products (eg, protamine sulfate test)
4. The investigation of hypercoagulable status (thrombotic tendency, thromboembolic disorders) covers both primary
causes (deficiencies of AT-III, protein C, protein S, and factor XII; fibrinolytic mechanisms) and secondary causes
(acquired platelet disorders and acquired diseases of coagulation and fibrinolytic impairment) and includes the
following tests:
a. PT
b. PTT
c. Fibrinogen test
d. Antiplatelet factors (eg, prostacyclin)
e. Anticoagulant factors (eg, AT-III, protein C, protein S, lupus anticoagulant)
f. Fibrinolysis tests (eg, fibrin degradation products [FDPs], euglobulin lysis time, fibrin monomers)
g. TT

NOTE
The lupus inhibitor (lupus anticoagulant) is an antibody (against the phospholipid used in the PT and PTT tests) that is
responsible for inhibition of the PT, PTT, Russell viper venom time (dRVVT), and kaolin clotting time (kCT). To
demonstrate its presence, 1 mL of the patient's plasma is mixed with 1 mL of normal plasma, and a PTT test of the
mixture is done. When an inhibitor of any sort is present, the PTT will not return to normal range. An inhibitor of the
lupus type can be shown by correcting the PTT through use of platelets as a phospholipid source or by demonstrating
a characteristic pattern in the PTT that results from sequential dilution of the phospholipid reagent. Lupus
anticoagulants may be associated with false-positive Venereal Disease Research Laboratory (VDRL) test reports and
with another antiphospholipid—the anticardiolipin antibody (ß 2-glycoprotein I).

Clinical Alert
Conditions associated with the presence of the lupus anticoagulant include:
1.
2.
3.
4.
5.
6.

SLE (one fifth of patients)
Multiple myeloma
Other autoimmune diseases (rheumatoid arthritis, Raynaud's syndrome)
Spontaneous abortions (associated with presence of anticardiolipin autoantibody) and postpartum complications
Lupus anticoagulant is more often associated with thromboembolism than with bleeding problems.
Most lupus anticoagulant antibodies are directed against prothrombin or ß 2-glycoprotein I.

Clinical Alert
1. All patients with hemorrhagic or thrombotic tendencies, or undergoing coagulation studies, should be observed
closely for possible bleeding emergencies. A comprehensive history and physical examination should be done.
2. Blood samples for coagulation studies should be drawn last if other blood studies are indicated.
3. Procedure alert: when a blood sample is obtained for PT, PTT, and TT, sodium citrate is used as the
anticoagulant in the sampling tubes.
Patient Assessment for Bleeding Tendency
1.
2.
3.
4.
5.
6.

Examine all skin for bruising.
Record petechiae associated with use of blood pressure cuffs or tourniquets.
Note bleeding from the nose or gums with no apparent cause.
Estimate blood quantity in vomitus, expectorated mucus, urine, stools, and menstrual flow.
Note prolonged bleeding from injection sites.
Watch for symptoms, especially changes in levels of consciousness or neurologic checks that may signal an
intracranial bleed.
7. Determine whether the patient is taking anticoagulants or aspirin.
Bleeding Time (Ivy Method; Template Bleeding Time)
Bleeding time measures the primary phase of hemostasis: the interaction of the platelet with the blood vessel wall and the
formation of a hemostatic plug. Bleeding time is the best single screening test for platelet function disorders and is one of
the primary screening tests for coagulation disorders.
This test is of value in detecting vascular abnormalities and platelet abnormalities or deficiencies. It is not recommended
for routine presurgical workup.
A small stab wound is made in either the earlobe or the forearm; the bleeding time (the amount of time it takes to form a
clot) is recorded. The duration of bleeding from a punctured capillary depends on the quantity and quality of platelets and
the ability of the blood vessel wall to constrict.
The principal use of this test today is in the diagnosis of von Willebrand's disease, an inherited defective molecule of
factor VIII and a type of pseudohemophilia. It has been established that aspirin may cause abnormal bleeding in some
normal persons, but the bleeding time test has not proved consistently valuable in identifying such persons.
Reference Values
Normal 3–10 minutes in most laboratories Duke method (earlobe): 5 minutes (not recommended—not very reproducible
with a wide range of normal values) Ivy method (forearm with template): 25–90 minutes Mielke's method (Surgicut):
Adults: 1–7 minutes Teens: 3.0–8 minutes Children: 2.5–13 minutes
Procedure (Ivy Method)
1. Cleanse the area three fingerwidths below the antecubital space with alcohol and allow to dry.
2. Place a blood pressure cuff on the arm above the elbow and inflate to 40 mm Hg.
3. Select a cleansed area of the forearm without superficial veins. Stretch the skin laterally and tautly between the
thumb and forefinger.
4. Start a stopwatch. Use the edge of a 4? × 4? filter paper to blot the blood through capillary action by gently
touching the drop every 30 seconds. Do not disturb the wound itself. Remove the blood pressure gauge when
bleeding stops and a clot has formed. Apply a sterile dressing when the test is completed.
5. Remember that the end point (by the Ivy or the earlobe method) is reached when blood is no longer blotted from the
forearm puncture. Report in minutes and half minutes (eg, 5 minutes, 30 seconds).
Clinical Implications
1. Bleeding time is prolonged when the level of platelets is decreased or when platelets are qualitatively abnormal:
a. Thrombocytopenia (platelet count <80 × 10 3 /mm 3)
b. Platelet dysfunction syndromes
c. Decrease or abnormality in plasma factors (eg, von Willebrand's factor, fibrinogen)
d. Abnormalities in the walls of the small blood vessels, vascular disease
e. Advanced renal failure
f. Severe liver disease
g. Leukemia, other myeloproliferative diseases
h. Scurvy
i. DIC disease (owing to the presence of FDPs)
2. In von Willebrand's disease, bleeding time can be variable; it will definitely be prolonged if aspirin is taken before
testing (aspirin tolerance test).
3. A single prolonged bleeding time does not prove the existence of hemorrhagic disease. Because a larger vessel
can be punctured, the puncture should be repeated on an alternate body site, and the two values obtained should
be averaged.
4. Bleeding time is normal in the presence of coagulation disorders other than platelet dysfunction, vascular disease,
or von Willebrand's disease.
5. Aspirin therapy (antiplatelet function therapy): when thrombus formation is thought to be mediated by platelet
activation, the patient frequently is given agents to interrupt normal platelet function, which may be monitored by
bleeding times or platelet aggregation studies. Aspirin is the most commonly used inhibitor; it inhibits platelet

adhesion or “stickiness.”
Interfering Factors
1.
2.
3.
4.
5.

Normal values for bleeding time vary when the puncture site is not of uniform depth and width.
Touching the puncture site during this test will break off fibrin particles and prolong the bleeding time.
Excessive alcohol consumption (as in alcoholic patients) may cause increased bleeding time.
Prolonged bleeding time can reflect ingestion of 10 g of aspirin as long as 5 days before the test.
Other drugs that may cause increased bleeding times include dextran, streptokinase-streptodornase (fibrinolytic
agents), mithramycin, pantothenyl alcohol (see Appendix J).
6. Extreme hot or cold conditions can alter the results.
7. Edema of patient's hands or cyanotic hands will invalidate the test.
Interventions
Pretest Patient Care
1.
2.
3.
4.
5.
6.

Explain test purpose and procedure. See Patient Assessment for Bleeding Tendency on page 131.
Instruct patient to abstain from aspirin and aspirin-like drugs for at least 7 days before the test.
Advise the patient to abstain from alcohol before the test.
Inform the patient that scar tissue may form at the puncture site (keloid formation).
If the patient has an infectious skin disease, postpone the test.
See Chapter 1 guidelines for safe, effective, informed pretest care.

Posttest Patient Aftercare
1. Interpret test outcome and monitor appropriately for prolonged bleeding. See Patient Assessment for Bleeding
Tendency on page 131.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
1. The critical value for bleeding time is >15 minutes.
2. If the puncture site is still bleeding after 15 minutes, discontinue the test and apply pressure to the site.
Document and report the results to the clinician.
Platelet Count; Mean Platelet Volume (MPV)
Platelets (thrombocytes) are the smallest of the formed elements in the blood. These cells are nonnucleated, round or
oval, flattened, disk-shaped structures. Platelet activity is necessary for blood clotting, vascular integrity and
vasoconstriction, and the adhesion and aggregation activity that occurs during the formation of platelet plugs that occlude
(plug) breaks in small vessels. Thrombocyte development takes place primarily in the bone marrow. The life span of a
platelet is about 7.5 days. Normally, two thirds of all the body platelets are found in the circulating blood and one third in
the spleen.
The platelet count is of value for assessing bleeding disorders that occur with thrombocytopenia, uremia, liver disease, or
malignancies and for monitoring the course of disease associated with bone marrow failure. This test is indicated when
the estimated platelet count (on a blood smear) appears abnormal. It is also part of a coagulation profile or workup.
The mean platelet volume (MPV) is sometimes ordered in conjunction with a platelet count. The MPV indicates the
uniformity of size of the platelet population. It is used for the differential diagnosis of thrombocytopenia.
Reference Values
Normal Platelet count: Adults: 140–400 × 10 3/mm 3 or 140–400 × 10 9/L Children: 150–450 × 10 3/mm 3 or 150–450 ×
10 9/L Mean platelet volume: Adults: 7.4–10.4 µm 3 or fL Children: 7.4–10.4 µm 3 or fL
Procedure
1. Mix a 7-mL venous blood sample with an EDTA anticoagulant tube.
2. Count the platelets by phase microscopy or by an automated counting instrument. The MPV is also calculated by
many instruments at the time of the platelet count.
3. Make a blood smear and note the size, shape, and clumping of the platelets.
4. Place the specimen in a biohazard bag.
Clinical Implications
1. Abnormally increased numbers of platelets (thrombocythemia, thrombocytosis) occur in:
a. Essential thrombocythemia
b. Chronic myelogenous and granulocytic leukemia, myeloproliferative diseases
c. Polycythemia vera and primary thrombocytosis
d. Splenectomy
e. Iron-deficiency anemia
f. Asphyxiation
g. Rheumatoid arthritis and other collagen diseases, SLE
h. Rapid blood regeneration caused by acute blood loss, hemolytic anemia

i. Acute infections, inflammatory diseases
j. Hodgkin's disease, lymphomas, malignancies
k. Chronic pancreatitis, tuberculosis, inflammatory bowel disease
l. Renal failure
m. Recovery from bone marrow suppression (thrombocytopenia)
2. Abnormally decreased numbers of platelets (thrombocytopenia) occur in:
a. Idiopathic thrombocytopenic purpura, neonatal purpura
b. Pernicious, aplastic, and hemolytic anemias
c. After massive blood transfusion (dilution effect)
d. Viral, bacterial, and rickettsial infections
e. Congestive heart failure, congenital heart disease
f. Thrombopoietin deficiency
g. During cancer chemotherapy and radiation, exposure to dichlorodiphenyl-trichloroethane (DDT) and other
chemicals
h. HIV infection
i. Lesions involving the bone marrow (eg, leukemias, carcinomas, myelofibrosis)
j. DIC and thrombotic thrombocytopenic purpura
k. Inherited syndromes such as Bernard-Soulier syndrome, May-Hegglin anomaly, Wiskott-Aldrich syndrome,
Fanconi's syndrome
l. Toxemia of pregnancy, eclampsia
m. Alcohol toxicity, ethanol abuse
n. Hypersplenism
o. Renal insufficiency
p. Antiplatelet antibodies
3. Increased MPV is observed in:
a. Idiopathic thrombocytopenic purpura (autoimmune)
b. Thrombocytopenia caused by sepsis
c. Prosthetic heart valve
d. Massive hemorrhage
e. Myeloproliferative disorders
f. Acute and chronic myelogenous leukemia
g. Splenectomy
h. Vasculitis
i. Megaloblastic anemia
4. Decreased MPV occurs in Wiskott-Aldrich syndrome.

Clinical Alert
1. In 50% of patients who exhibit unexpected platelet increases, a malignancy is found.
2. In patients with an extremely elevated platelet count (>1000 × 10 3/mm 3 or >1000 × 10 9/L) as a result of a
myeloproliferative disorder, assess for bleeding caused by abnormal platelet function.

NOTE
Many drugs have toxic effects. The dosage does not have to be high to be toxic. Toxic thrombocytopenia depends on
the inability of the body to metabolize and secrete the toxic substance.

Clinical Alert
1. Panic values: a decrease in platelets to <20 × 10 3 /mm 3 or <20 × 10 9/L is associated with a tendency for
spontaneous bleeding, prolonged bleeding time, petechiae, and ecchymosis.
2. Platelet counts >50 × 10 3/mm 3 or >50 × 10 9/L are not generally associated with spontaneous bleeding.
Interfering Factors
1.
2.
3.
4.
5.

Platelet counts normally increase at high altitudes; after strenuous exercise, trauma, or excitement; and in winter.
Platelet counts normally decrease before menstruation and during pregnancy.
Clumping of platelets may cause falsely lowered results.
Oral contraceptives cause a slight increase.
See Appendix J for drugs that affect test outcomes.

Interventions
Pretest Patient Care
1.
2.
3.
4.

Explain test purpose and procedure.
Avoid strenuous exercise before blood is drawn.
Note what medications and what treatments the patient is receiving.
See Chapter 1 guidelines for safe, effective, informed pretest care.

Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately. Observe for signs and symptoms of gastrointestinal bleeding,
hemolysis, hematuria, petechiae, vaginal bleeding, epistasis, and bleeding from the gums. When hemorrhage is
apparent, use emergency measures to control bleeding and notify the attending physician.
2. Use platelet transfusions if the platelet count is <20 × 10 3/mm 3 (<20 × 10 9/L) or if there is a specific bleeding

lesion. One unit of platelet concentrate raises the count by 15 × 10 3/mm 3 (15 × 10 9/L).
3. See Chapter 1 guidelines for safe, effective, informed posttest care .
Platelet Aggregation
Platelet aggregation is used to evaluate congenital qualitative functional disorders of adhesion, release, or aggregation.
It is rarely used to evaluate acquired bleeding disorders.
Reference Values
Normal Full platelet aggregation in response to the following: Adenosine diphosphate Collagen Epinephrine Thrombin
Ristocetin
Procedure
1. Obtain a 5-mL venous blood sample (anticoagulated in a tube containing sodium citrate).
2. Place it in biohazard bag. The sample is kept at room temperature ( never refrigerate) and must be run within 30
minutes after the blood is drawn.
3. Increase the transmission of light through a sample of platelet-rich plasma when platelets aggregate. This increase
in light transmission can be used as an index to the aggregation in response to various agonists.
Clinical Implications
1. Decreased platelet aggregation occurs in congenital diseases:
a. Bernard-Soulier syndrome
b. Glanzmann's thrombasthenia
c. Storage pool diseases (eg, Chédiak-Higashi syndrome, gray platelet disease)
d. Cyclooxygenase deficiency
e. Wiskott-Aldrich syndrome
f. Albinism
g. ß-Thalassemia major
h. May-Hegglin anomaly
i. Various connective tissue disorders (eg, Marfan's syndrome)
j. von Willebrand's disease
2. Decreased platelet aggregation also occurs in acquired disorders:
a. Uremia
b. Antiplatelet antibodies
c. Cardiopulmonary bypass
d. Myeloproliferative disorders
e. Dysproteinemias (macroglobulinemia)
f. Idiopathic thrombocytopenic purpura
g. Polycythemia vera
h. Use of drugs and aspirin, some antibiotics, anti-inflammatory drugs, psychotropic drugs, and others (see
Appendix J)
i. DIC
3. Increased aggregation occurs in primary and secondary Raynaud's syndrome.
Interfering Factors
1. Platelet count <100,000/mm 3
2. Patient cannot be taking drugs that interfere with aggregation (see Appendix J).
3. Lipemia will interfere with testing.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Be aware that for 10 days before test, drugs that inhibit platelet aggregation are contraindicated. These include
aspirin, antihistamines, steroids, cocaine, anti-inflammatories, theophylline, and antibiotics.
3. On the day of the test, avoid caffeine.
4. Avoid warfarin (Coumadin) for 2 weeks and heparin therapy for 1 week before testing.
5. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome and counsel appropriately for congenital disorders.
2. Resume medications and normal diet.
3. See Chapter 1 guidelines for safe, effective, informed posttest care .
Thrombin Time (TT); Thrombin Clotting Time (TCT)
Stage III fibrinogen defects can be detected by the TT test. It can detect DIC and hypofibrinogenemia and may also be
used for monitoring streptokinase therapy. The test actually measures the time needed for plasma to clot when thrombin
is added. Normally, a clot forms rapidly; if it does not, a stage III deficiency is present ( Fig. 2.1). A TT test is often
included as part of a panel for coagulation defects.

FIGURE 2.1 Intrinsic, extrinsic, and common pathways of coagulation. Vessel injury initiates intrinsic pathway through
contact activation by exposed collagen. Extrinsic pathway is initiated by endothelial release of tissue factor (ie, tissue
thromboplastin). Extrinsic and intrinsic pathways each initiate common pathway to create stable fibrin clot.
(Lotspeich-Steininger, C. A., et al. [1992]. Clinical Hematology, Philadelphia: JB Lippincott Co.)
Reference Values
Normal 7.0–12.0 seconds (varies widely by laboratory) Check with your laboratory for values.
Procedure
1. Use the procedure for two-tube specimen collection to anticoagulate a 7-mL venous blood sample with sodium
citrate and put on ice. Take care not to contaminate the specimen with heparin from IV apparatus or other sources.
2. Ensure that the specimen is tested within 2 hours, or it must be frozen for later testing.
Clinical Implications
1. Prolonged TT occurs in:
a. Hypofibrinogenemia
b. Therapy with heparin or heparin-like anticoagulants
c. DIC
d. Fibrinolysis
e. Multiple myeloma
f. Presence of large amounts of fibrin split products (FSPs) or FDPs, as in DIC
g. Uremia
h. Severe liver diseases
2. Shortened TT occurs in:
a. Hyperfibrinogenemia
b. Elevated Hct (>55%)
3. Therapy with plasminogen activators—streptokinase, urokinase, or tissue plasminogen activator (tPA).
Anticoagulant therapy is an attempt either to prevent thrombus formation or to promote thrombus lysis. The type
and location of the thrombus usually determine the type of anticoagulant to be administered and the treatment
protocol. The newest treatment for life-threatening thrombus formation uses plasminogen activators to accelerate
fibrinolysis, which is the enzymatic dissolution of already organized clots ( Fig. 2.2). The action of some of these
agents produces a lytic state that can be monitored by the TT.

FIGURE 2.2 Stage Four Activation of the Fibrinolytic System

Although several tests are sensitive to the effects of thrombolytic drugs, many require lengthy assay procedures or
special techniques. Of the laboratory procedures that have been recommended (PT, TT, APTT, quantitative fibrinogen,
euglobulin clot lysis, and plasminogen levels), the TT has become widely accepted because it is fast and practical, does
not require special equipment, and can detect the decrease in fibrinogen levels as well as the presence of fibrin and
FDPs. The half-life for these activators is relatively short (10–90 minutes); therefore, the antidote for overdose is to hold
giving the next dose.

Clinical Alert
TT is severely prolonged in the presence of afibrinogenemia (<80 mg/dL or <0.8 g/L of fibrinogen). Critical value: >60
seconds.
Interfering Factors
1. Heparin prolongs thrombin time. Interpret test results within this context.
2. Plasminogen activator therapy prolongs TCT.
3. See Appendix J for drugs that affect test outcomes.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. If possible, ensure that no heparin is taken for 2 days before testing.
3. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Resume normal activities and medications as ordered.
2. Interpret test outcomes and monitor appropriately. Check for excess bleeding. If plasminogen activator is being
monitored, see Posttest Patient Aftercare for APTT, pages 142–143.
3. See Chapter 1 guidelines for safe, effective, informed posttest care .
Partial Thromboplastin Time (PTT); Activated Partial Thromboplastin Time (APTT)
The PTT, a one-stage clotting test, screens for coagulation disorders. Specifically, it can detect deficiencies of the
intrinsic thromboplastin system and also reveals defects in the extrinsic coagulation mechanism pathway.

NOTE
The PTT and APTT test for the same functions. APTT is a more sensitive version of PTT that is used to monitor
heparin therapy.
The APTT is used to detect deficiencies in the intrinsic coagulation system, to detect incubating anticoagulants, and to
monitor heparin therapy. It is part of a coagulation panel workup.
Reference Values
Normal APTT: 21–35 seconds Check with your laboratory for therapeutic range values during heparin therapy (2–2.5
times normal).
Procedure
1. Obtain a 5-mL venous blood sample and anticoagulate with sodium citrate. Use the two-tube method. Place the
specimen in a biohazard bag.
2. Do not draw blood samples from a heparin lock or heparinized catheter.
3. Be aware that the sample may be transported at room temperature, but the vacuum must be intact (do not remove
stopper). It is stable for 12 hours.
Clinical Implications
1. Prolonged APTT occurs in:
a. All congenital deficiencies of intrinsic system coagulation factors, including hemophilia A and hemophilia B
b. Congenital deficiency of Fitzgerald's factor, Fletcher's factor (prekallikrein)
c. Heparin therapy, streptokinase, urokinase
d. Warfarin (Coumadin)-like therapy
e. Vitamin K deficiency
f. Hypofibrinogenemia
g. Liver disease
h. DIC (chronic or acute)
i. Fibrin breakdown products
2. When APTT is performed in conjunction with PT, a further clarification of coagulation defects is possible. For
example, a normal PT with an abnormal APTT means that the defect lies within the first stage of the clotting
cascade (factors VIII, IX, X, XI, and/or XII). The pattern of a normal PTT with an abnormal PT suggests a possible
factor VII deficiency. If both PT and APTT are prolonged, a deficiency of factor I, II, V, or X is suggested. Used
together, APTT and PT will detect approximately 95% of coagulation defects.
3. Shortened APTT occurs in:
a. Extensive cancer, except when the liver is involved
b. Immediately after acute hemorrhage
c. Very early stages of DIC
4. Circulating anticoagulants (inhibitors) usually occur as inhibitors of a specific factor (eg, factor VIII). These are most
commonly seen in the development of anti–factor VIII or anti–factor IX in 5% to 10% of hemophiliac patients.
Anticoagulants that develop in the treated hemophiliac are detected through prolonged APTT. Circulating
anticoagulants are also associated with other conditions:

a. After many plasma transfusions
b. Drug reactions
c. Tuberculosis
d. Chronic glomerulonephritis
e. SLE
f. Rheumatoid arthritis
5. Heparin therapy: In deep vein thrombosis or acute myocardial infarction, the usual protocol requires injection of
heparin (monitored by the APTT), followed by long-term therapy with oral anticoagulants (monitored by the PT,
APTT, or both).
a. In the blood, heparin combines with an a-globulin (heparin cofactor) to form a potent antithrombin. It is a direct
anticoagulant.
b. Intravenous heparin injection produces an immediate anticoagulant effect; it is chosen when rapid anticoagulant
effects are desired.
c. Because the half-life of heparin is 3 hours, the APTT is measured 3 hours after heparin administration, or 1 hour
before the next dose.
d. Therapeutic APTT levels are ordinarily maintained at 2 to 2.5 times the normal values.
e. To evaluate heparin effects, blood is tested:
1. For baseline values before therapy is initiated
2. One hour before the next dose is due (when a 4-hour administration cycle is ordered)
3. According to the patient's status (eg, bleeding)

NOTE
Mixing equal parts of patient plasma and normal plasma corrects the APTT if it is caused by a coagulation factor defect
but does not correct the APTT to normal if it is caused by a circulating inhibitor. A more sensitive test is the Russell
viper venom test, which demonstrates the presence of the lupus anticoagulant. This test is unaffected by inhibitors of
factor VIII or deficiencies of factors VIII, IX, XI, or is affected by deficiencies of factors II, V, or X and by the use of
sodium, warfarin, or heparin. Because lupus-type anticoagulants vary greatly in their reactivity in various test systems,
it is recommended that this test be done in conjunction with the APTT and the anticardiolipin antibody assay. The
reference range is 33.5–41.5 seconds.

Clinical Alert
Panic value: APTT >70 seconds signifies spontaneous bleeding.

NOTE
Not all individuals respond ideally or predictably to heparin. Anaphylaxis and erythematous may occur. There is no
shortcut to adequate and safe anticoagulation.
Interfering Factors
1.
2.
3.
4.

See Appendix J for drugs that affect test outcomes.
Hemolized plasma shortens APTT in normal patients but not in abnormal (heparinized) patients.
Very increased or decreased Hct
Incorrect ratio of blood to citrate (“short” fill of blood in collection tube)

Interventions
Pretest Patient Care
1. Explain test purpose, procedure, benefits, and risks.
2. See Chapter 1 guidelines for safe, effective, informed, pretest care .
3. Draw blood sample 1 hour before next dose of heparin. The heparin dose given relates to the APTT result.
Posttest Patient Aftercare
1. Interpret test outcome and monitor appropriately. Protamine sulfate is the antidote for heparin overdose or for
reversal of heparin anticoagulation therapy.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
3. Watch for signs of spontaneous bleeding; notify physician immediately and treat accordingly.
4. Alert the patient to watch for bleeding gums, hematuria, oozing from wounds, and excessive bruising.
5. Instruct the patient to use an electric shaver instead of a blade and to exercise caution in all activities.
6. Avoid use of aspirin or ASA-like drugs (unless specifically prescribed) because they contribute to bleeding
tendencies.
7. Be aware that long-term use of heparin can cause development of osteoporosis with fractures.
8. Remember that thrombocytopenia can also develop with high-dose heparin therapy, along with progressive
thomboembolytic syndrome. This platelet abnormality quickly reverses when heparin is discontinued.
Activated Coagulation Time (ACT)
The ACT test evaluates coagulation status. The ACT responds linearly to heparin level changes and responds to wider
ranges of heparin concentrations than does the APTT. The ACT however, assays overall coagulation activity. Therefore,
prolonged values may not be exclusively the result of heparin.
The ACT can be a bedside procedure and requires only 0.4 mL of blood. Heparin infusion or reversal with protamine can

then be titrated almost immediately according to the ACT results. ACT also is routinely used during dialysis, coronary
artery bypass procedures, arteriograms, and percutaneous transluminal coronary arteriography. This test is hard to
standardize, and no controls are available; therefore, it is used with caution mainly in cardiac surgery. The results are
backed up by the APTT.
Reference Values
Normal ACT: 70–120 seconds Therapeutic range: 180–240 seconds (two times normal range)
Prothrombin Time (Pro Time; PT)
Prothrombin is a protein produced by the liver for clotting of blood. Prothrombin production depends on adequate vitamin
K intake and absorption. During the clotting process, prothrombin is converted to thrombin. The prothrombin content of
the blood is reduced in patients with liver disease.
The PT is one of the four most important screening tests used in diagnostic coagulation studies. It directly measures a
potential defect in stage II of the clotting mechanism (extrinsic coagulation system) through analysis of the clotting ability
of five plasma coagulation factors (prothrombin, fibrinogen, factor V, factor VII, and factor X). In addition to screening for
deficiency of prothrombin, the PT is used to evaluate disfibrinogenemia, evaluate the heparin effect and coumarin effect,
liver failure, and vitamin K deficiency.
Reference Values
Normal PT: 11.0–13.0 seconds (can vary by laboratory) Therapeutic levels are at a P/C ratio of 2.0–2.5. Recommended
therapeutic ranges are shown in Table 2.7.
Table 2.7 Therapeutic Context
INR
Preoperative oral anticoagulant started 2 weeks before surgery
Non–hip surgery
Hip surgery
Primary and secondary prevention of deep vein thrombosis
Prevention of systemic embolism in patients with atrial fibrillation
Recurrent systemic embolism
Prevention of recurrent deep vein thrombosis (two or more episodes)
Cardiac stents
Prevention of arterial thrombosis, including patients with mechanical heart valves

Target

1.5–2.5 2.0
2.0–3.0 2.5
2.0–3.0 2.5
2.0–3.0 2.5
3.0–4.5 3.5
2.5–4.0 3.0
3.0–4.5 3.5
3.0–4.5 3.5

P/C ratio (prothrombin time ratio): the observed patient PT divided by the laboratory PT mean normal value INR
(International Normalized Ratio): a comparative rating of PT ratios (representing the observed PT ratio adjusted by the
International Reference Thromboplastin) ISI (International Sensitivity Index): a comparative rating of thromboplastin
(supplied by the manufacturer of the reagent)
Procedure
1. Draw a 5-mL venous blood sample (by the two-tube technique) into a tube containing a calcium-binding
anticoagulant (sodium citrate). The ratio of sodium citrate to blood is critical.
2. Use blue-topped vacuum tubes that keep prothrombin levels stable at room temperature for 12 hours if left capped
(vacuum intact). Place the specimen in biohazard bag.
Oral Anticoagulant Therapy Oral anticoagulant drugs (eg, Coumadin, dicumarol) are commonly prescribed to treat
blood clots. These are indirect anticoagulants (compared with heparin, which is a direct anticoagulant). However, if
necessary, heparin is the anticoagulant of choice for initiating treatment because it acts rapidly and also partially lyses
the clot.
1. These drugs act via the liver to delay coagulation by interfering with the action of the vitamin K–related factors (II,
VII, IX, and X), which promote clotting.
2. Oral anticoagulants delay vitamin K formation and cause the PT to increase as a result of decreased factors II, VII,
IX, and X.
3. The usual procedure is to run a PT test every day when beginning therapy. The anticoagulant dose is adjusted until
the therapeutic range is reached. Then, weekly to monthly PT testing continues for the duration of therapy.
4. Coumadin takes 48 to 72 hours to cause a measurable change in the PT (3–4 days of drug therapy).
Drug Therapy and PT Protocols
1. Patients with cardiac problems are usually maintained at a PT level 2 to 2.5 times the normal (baseline) values.
2. Use of the INR values allows more sensitive control. A reasonable INR target for virtually all thromboembolic
problems is 2.0 to 3.0. See Table 2.7 more specific guidelines.
3. For treatment of blood clots, the PT is maintained within the 2 to 2.5 times normal range. If the PT drops below this
range, treatment may be ineffective, and old clots may expand or new clots may form. Conversely, if the PT rises
above 30 seconds, bleeding or hemorrhage may occur.
Clinical Implications
1. Conditions that cause increased PT include:

a. Deficiency of factors II (prothrombin), V, VII, or X
b. Vitamin K deficiency, newborns of mother with vitamin K deficiency
c. Hemorrhagic disease of the newborn
d. Liver disease (eg, alcoholic hepatitis), liver damage
e. Current anticoagulant therapy with warfarin (Coumadin)
f. Biliary obstruction
g. Poor fat absorption (eg, sprue, celiac disease, chronic diarrhea)
h. Current anticoagulant therapy with heparin
i. DIC
j. Zollinger-Ellison syndrome
k. Hypofibrinogenemia (factor I deficiency), dysfibrinogenemia
l. (Circulating anticoagulants), lupus anticoagulant
m. Premature newborns
2. Conditions that do not affect the PT include:
a. Polycythemia vera
b. Tannin disease
c. Christmas disease (factor IX deficiency)
d. Hemophilia A (factor VIII deficiency)
e. von Willebrand's disease
f. Platelet disorders (idiopathic thrombocytopenic purpura)
Interfering Factors
1. Diet: ingestion of excessive green, leafy vegetables increases the body's absorption of vitamin K, which promotes
blood clotting.
2. Alcoholism or excessive alcohol ingestion prolongs PT levels.
3. Diarrhea and vomiting decrease PT because of dehydration.
4. Quality of venipuncture: PT can be shortened if technique is traumatic and tissue thromboplastin is introduced to
the sample and if collection tube is not filled properly.
5. Influence of prescribed medications: antibiotics, aspirin, cimetidine, isoniazid, phenothiazides, cephalosporins,
cholestyramines, phenylbutazone, metronidazole, oral hypoglycemics, phenytoin
6. Prolonged storage of plasma at 4°C—activates factor VII and shortens PT
Interventions
Pretest Patient Care
1. Explain the purpose, procedure, and need for frequent testing. Emphasize the need for regular monitoring through
frequent blood testing if long-term therapy is prescribed. Do not refer to anticoagulants as “blood thinners.” One
explanation might be, “Your blood will be tested periodically to determine the pro time, which is an indication of how
the blood clots.” The anticoagulant dose will be adjusted according to PT results.
2. Caution against self-medication. Ascertain what drugs the patient has been taking. Many drugs, including
over-the-counter medications, alter the effects of anticoagulants and the PT value. Aspirin, acetaminophen, and
laxative products should be avoided unless specifically ordered by the physician.
3. Instruct the patient never to start or discontinue any drug without the doctor's permission. This will affect PT values
and may also interfere with the healing process.
4. Counsel regarding diet. Excessive amounts of green, leafy vegetables (eg, spinach, broccoli) will increase vitamin
K levels and could interfere with anticoagulant metabolism. Caution against using razor blades; electric shavers
should be used.
5. Remember that these guidelines also apply to aftercare.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately with follow-up testing and observation.
2. Avoid intramuscular injections during anticoagulant therapy because hematomas may form at the injection site. As
the PT increases to upper limits (>30 seconds), assess carefully for bleeding from different areas; this may require
neurologic assessment (if cranial bleeding is suspected), lung assessment and auscultation, gastrointestinal and
genitourinary assessments, or other assessments as appropriate. Instruct the patient to observe for bleeding from
gums, blood in the urine, or other unusual bleeding. Advise that care should be exercised in all activities to avoid
accidental injury.
3. Alert patients who are being monitored by PT for long-term anticoagulant therapy that they should not take any
other drugs unless they have been specifically prescribed.
4. Remember that when unexpected adjustments in anticoagulant doses are required to maintain a stable PT, or when
there are erratic changes in PT levels, a drug interaction should be suspected and further investigation should take
place.
5. Make changes in exercise intensity gradually or not at all. Active sports and contact sports should be avoided
because of the potential for injury.
6. See Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
1.
2.
3.
4.
5.

Critical value: If P/C is >2.5 or >30.0 seconds, notify clinician (for patients on anticoagulant).
If PT is excessively prolonged (>30 seconds), vitamin K may be ordered.
Critical value: >20 seconds (for nonanticoagulated persons)
Baseline PT levels should be determined before anticoagulant administration.
Critical value: INR >3.6; notify clinician (for patients on anticoagulants)

Coagulant Factors (Factor Assay)
Assay of specific factors of coagulation is done in the investigation of inherited and acquired bleeding disorders. For
example, tests of factor VIII–related antigen are used in the differential diagnosis of classic hemophilia and von
Willebrand's disease in cases in which there is no family history of bleeding and bleeding times are borderline or
abnormal. A test for ristocetin cofactor is done to help diagnose von Willebrand's disease by determining the degree or
rate of platelet aggregation that is taking place.
Reference Values
Normal Factor II—prothrombin: 80%–120% of normal Factor V—labile factor: 50%–150% of normal Factor VII—stable
factor: 65%–140% of normal or 65–135 AU Factor VIII—antihemophilic factor: 55%–145% of normal or 55–145 AU
Factor IX—Christmas factor: 60%–140% of normal or 60–140 AU Factor X: 45%–155% of normal or 45–155 AU Factor
XI: 65%–135% of normal or 65–135 AU Factor XII—Hageman factor: 50%–150% of normal or 50–150 AU Ristocetin (von
Willebrand's factor): 45%–140% of normal or 45–140 AU Factor VIII antigen: 100 µg/L or 50%–150% of normal or
50–150 AU Factor VIII–related antigen: 45%–185% of normal or 45–185 AU Fletcher's factor (prekallikrein): 80%–120%
of normal or 0.80–1.20 Critical value for any coagulation factor: <10% of normal
Procedure
1. Draw a 5-mL venous blood sample by the two-tube method and add to a collection tube containing sodium citrate
as the anticoagulant.
2. Cap samples, put on ice, and send to the laboratory as soon as possible.
Clinical Implications
1. Inherited deficiencies:
a. Any of the specific factors—I, II, V, VII, VIII, IX, X, XI, XII, and XIII—may be deficient on a familial basis.
b. Factor VII is decreased in hypoproconvertinemia (autosomal recessive).
c. Factor VIII is decreased in classic hemophilia A and von Willebrand's disease (inherited autosomally).
d. Factor IX is decreased in Christmas disease or hemophilia B (sex-linked recessive).
e. Factor XI is decreased in hemophilia C (autosomal dominant, occurring predominantly in Jews).
2. Acquired disorders:
a. Factor II is decreased in:
1. Liver disease
2. Vitamin K deficiency
3. Oral anticoagulants (last factor to decrease after starting Coumadin therapy)
4. Normal newborns
5. Circulating inhibitors or lupus-like anticoagulants
b. Factor V is decreased in:
1. Liver disease
2. Factor V inhibitors
3. Myeloproliferative disorders
4. DIC and fibrinolysis
5. Normal newborns (mildly decreased)
c. Factor VII is decreased in:
1. Liver disease
2. Treatment with coumarin-type drugs (first factor to decrease)
3. Normal newborns
4. Kwashiorkor
d. Factor VIII is increased in:
1. Late normal pregnancy
2. Thromboembolic conditions
3. Liver disease
4. Postoperative period
5. Rebound activity after sudden cessation of a coumarin-type drug
6. Normal newborns
e. Factor VIII is decreased in:
1. Presence of factor VIII inhibitors (anticoagulants capable of specifically neutralizing a coagulation factor and
thereby disrupting hemostasis), associated with hemophilia A and immunologic reactions, and postpartum
2. von Willebrand's disease
3. DIC, fibrinolysis
4. Myeloproliferative disorders
f. Factor IX is decreased in:
1. Uncompensated cirrhosis, liver disease
2. Nephrotic syndrome
3. Development of circulating anticoagulants against factor IX (rare)
4. Normal newborns
5. Dicumarol and related anticoagulant drugs
6. DIC
7. Vitamin K deficiency
g. Factor X is decreased in:
1. Vitamin K deficiency
2. Liver disease
3. Oral anticoagulants
4. Amyloidosis
5. DIC

6. Normal newborns
h. Factor XI is decreased in:
1. Liver disease
2. Intestinal malabsorption (vitamin K)
3. Occasional development of circulatory anticoagulants against factor IX
4. DIC
5. Newborns (do not reach adult levels for up to 6 months)
i. Factor XII is decreased in:
1. Nephrotic syndrome
2. Liver disease
3. Chronic granulocytic leukemia
4. Normal newborns
j. Factor XIII is decreased in:
1. Postoperative patients
2. Liver disease
3. Persistent increased fibrinogen levels
4. Obstetric complications with hypofibrinogenemia
5. Acute myelogenous leukemia
6. Circulating anticoagulants
7. DIC
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .
Plasminogen (Plasmin; Fibrinolysin)
Plasminogen is a glycoprotein, synthesized in the liver, present in plasma. Under normal circumstances, plasminogen is
a part of any clot because of the tendency of fibrin to absorb plasminogen from the plasma. When plasminogen activators
perform their function, plasmin is formed within the clot; this gradually dissolves the clot while leaving time for tissue
repair. Free plasmin also is released to the plasma; however, antiplasmins there immediately destroy any plasmin
released from the clot (see Fig. 2.2).
This test is done to determine plasminogen activity in persons with thrombosis or DIC. When pathologic coagulation
processes are involved, excessive free plasmin is released to the plasma. In these situations, the available antiplasmin is
depleted, and plasmin begins destroying components other than fibrin, including fibrinogen, factors V and VIII, and other
factors. Plasmin acts more quickly to destroy fibrinogen because of fibrinogen's instability.
For therapeutic destruction of thrombi, urokinase, a trypsin-like protease purified from urine, may be administered to a
patient to activate plasminogen to plasmin and induce fibrinolysis. Streptokinase is another therapeutic agent used for
the same purpose.
Reference Values
Normal Plasminogen activity Males: 76%–124% of normal for plasma or 0.76–1.24 fraction of normal Females:
65%–153% of normal for plasma or 0.65–1.53 fraction of normal Infants: 27%–59% of normal for plasma or 0.27–0.59
fraction of normal
Procedure
1. Add a 5-mL venous blood sample to a collection tube containing sodium citrate. Use the two-tube method. Place
the specimen in a biohazard bag.
2. Put the sample on ice and transport to the laboratory immediately.
3. Be aware that the test must be started within 30 minutes after the blood is drawn.
Clinical Implications
1. Decreased plasminogen activity occurs in:
a. Some familial or isolated cases of idiopathic deep vein thrombosis
b. DIC and systemic fibrinolysis
c. Liver disease and cirrhosis
d. Neonatal hyaline membrane disease
e. Therapy with plasminogen activators
2. Decreased levels of plasminogen or abnormally functioning plasminogen can lead to venous and arterial clotting
(thrombosis).
3. Increased plasminogen activity occurs in:
a. Pregnancy (third trimester)
b. Regular vigorous physical exercise
Interfering Factors See Appendix J for drugs that affect test outcomes.

Interventions
Pretest Patient Preparation
1. Explain test purpose and procedure.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately for thrombotic tendency.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .
Fibrinolysis (Euglobulin Lysis Time; Diluted Whole Blood Clot Lysis)
Primary fibrinolysis, without any sign of intravascular coagulation, is extremely rare. Secondary fibrinolysis is usually
seen and follows or occurs simultaneously with intravascular coagulation. This secondary fibrinolysis is a protective
mechanism against generalized clotting.
This test is done to evaluate a fibrinolytic activity. Shortened time indicates excessive fibrinolytic activity. Lysis is marked
and rapid with primary fibrinolysis but can be minimal in secondary fibrinolysis. The diluted whole blood is used to
monitor urokinase and streptokinase therapy.
Reference Values
Normal Euglobulin lysis—no lysis of plasma clot at 37°C in 60–120 minutes. The clot is observed for 24 hours. Diluted
whole blood clot lysis: no lysis of clot in 120 minutes at 37°C.
Procedure

NOTE
To avoid release of plasminogen activator, do not massage vein, pump fist, or leave tourniquet on for a prolonged
period of time.
1. Collect a 5-mL venous blood sample in a tube containing sodium citrate using the two-tube method. Place the
specimen in a biohazard bag.
2. Put the sample on ice and transport to the laboratory immediately, or start at bedside.
3. Be aware that the test must be started within 90 minutes after the blood is centrifuged.

Clinical Alert
A lysis time <1 hour signifies that abnormal fibrinolysis is occurring.
Clinical Implications
1. Increased fibrinolysis time occurs in the following conditions:
a. Primary fibrinolysis
b. Within 48 hours after surgery
c. Cancer of prostate or pancreas
d. Circulatory collapse, shock
e. During lung and cardiac surgery
f. Obstetric complications (eg, antepartum hemorrhage, amniotic embolism, septic abortion, death of fetus,
hydatidiform mole)
g. Long-term DIC (may be normal if plasminogen is depleted)
h. Liver disease
i. Administration of plasminogen activators (tPA, streptokinase, urokinase)
2. Heparin does not interfere with the euglobulin lysis test.
Interfering Factors
1. Increased fibrinolysis occurs with moderate exercise and increasing age.
2. Decreased fibrinolysis occurs in arterial blood, compared with venous blood. This difference is greater in
arteriosclerosis (especially in young persons).
3. Decreased fibrinolysis occurs in postmenopausal women and in normal newborns.
4. FDPs interfere with fibrinolysis.
5. Normal results can occur if fibrinolysis is far advanced (plasminogen depleted).
6. Fibrinolysis is increased by very low fibrinogen levels (<80 mg/dL or <0.8 g/L) and decreased by high fibrinogen
levels.
7. Increased fibrinolysis can be caused by traumatic venipuncture or a tourniquet that is too tight.
8. See Appendix J for drugs that affect test outcomes.
Interventions
Patient Preparation
1. Advise patient of test purpose and procedure; no exercise before test.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.

Patient Aftercare
1. Interpret test results and monitor appropriately for fibrinolytic crisis.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .
Fibrin Split Products (FSPs); Fibrin Degradation Products (FDPs)
When fibrin is split by plasmin, positive tests for fibrin degradation (split) products, identified by the letters X, Y, D, and E,
are produced. These products have an anticoagulant action and inhibit clotting when they are present in excess in the
circulation. Increased levels of FDPs may occur with a variety of pathologic processes in which clot formation and lysis
occur.
This test is done to establish the diagnosis of DIC and other thromboembolic disorders.
Reference Values
Normal Negative at 1:4 dilution or <10 µg/mL (<10 mg/L)
Procedure
1. Place a venous blood sample of at least 4.5 mL in a tube containing thrombin and an inhibitor of fibrinolysis
(reptilase, aprotinin, and calcium). Place the specimen in a biohazard bag.
2. Be aware that blood must be completely clotted before the test is started for the test to be valid because fibrinogen
is broken down into identical fragments. Therefore, no fibrinogen can be present when the test is done.
Clinical Implications Increased FSP and FDP is associated with any condition associated with DIC (see page 128 for
examples) and in:
1.
2.
3.
4.
5.
6.
7.

Primary fibrinolysis
Venous thrombosis
Thoracic and cardiac surgery or renal transplantation
Acute myocardial infarction
Pulmonary embolism
Carcinoma
Liver disease

Interfering Factors
1. Because all of the laboratory methods are sensitive to fibrinogen as well as FDP, it is essential that no unclotted
fibrinogen be left in the serum preparation. False-positive reactions can result if any fibrinogen is present.
2. False-positive results occur with heparin therapy.
3. The presence of rheumatoid factor (rheumatoid arthritis) may cause falsely high FSP and FDP values.
4. See Appendix J for drugs that affect test outcomes.
Interventions
Patient Preparation
1. Explain test purpose and procedure.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Patient Aftercare
1. Interpret test results and monitor appropriately for DIC and thrombosis.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
1. Patients with very high levels of FSP/FDP have blood that does not clot or clots poorly.
2. Critical value: >40 µg/mL (>40 mg/L)
D-Dimer
D-Dimers are produced by the action of plasmin on cross-linked fibrin. They are not produced by the action of plasmin on
unclotted fibrinogen or FDPs and therefore are specific for fibrin. The presence of D-dimer confirms that both thrombin
generation and plasmin generation have occurred.
This test is used in the diagnosis of DIC disease and to screen for venous thrombosis and acute myocardial infarction.
The D-dimer test is more specific for DIC than are tests for FSPs. The test verifies in vivo fibrinolysis because D-dimers
are produced only by the action of plasmin on cross-linked fibrin, not by the action of plasmin on unclotted fibrinogen. A
positive D-dimer test is presumptive evidence for DIC but is not diagnostic.
Reference Values
Normal <250 µg/L or <1.37 nmol/L Qualitative: no D-dimer fragments present
Procedure A venous blood sample or 5 mL is collected into a tube containing sodium citrate and apotinin. Place the
specimen in biohazard bag and return to lab immediately.

Clinical Implications
1. Increased D-dimer values are associated with:
a. DIC (secondary fibrinolysis)
b. Arterial or venous thrombosis (deep vein thrombosis)
c. Renal or liver failure
d. Pulmonary embolism
e. Late in pregnancy, preeclampsia
f. Myocardial infarction
g. Malignancy, inflammation, and severe infection
2. D-Dimer values are increased with tPA anticoagulant therapy.

NOTE
D-Dimer analysis of spinal fluid can rapidly and accurately differentiate cases of subarachnoid hemorrhage (SAH) from
a traumatic tap. Positive in SAH.
Interfering Factors
1.
2.
3.
4.

False-positive tests are obtained with high titers of rheumatoid factor.
False-positive D-dimer levels increase as the tumor marker CA-125 for ovarian cancer increases.
The D-dimer test will be positive in all patients after surgery or trauma.
False-positive results found in estrogen therapy, normal pregnancy

Interventions
Patient Preparation
1. Explain test purpose and procedure.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Patient Aftercare
1. Interpret test outcome and monitor appropriately for DIC or thrombin.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .
Fibrinopeptide A (FPA)
Fibrinopeptides A and B are formed by the action of thrombin on fibrinogen; therefore, the presence of FPA indicates that
thrombin has acted on fibrinogen.
The measurement is the most sensitive assay done to determine thrombin action. FPA reflects the amount of active
intravascular blood clotting; this occurs in a subclinical DIC, which is common in patients with leukemia of various types
and may be associated with tumor progression. FPA elevations can occur without intravascular thrombosis, decreasing
the value of a positive test.
Reference Values
Normal Male: 0.4–2.6 mg/mL Female: 0.7–31 mg/mL
Procedure
1. Collect a venous blood sample of 5 mL in special Vacutainer tube containing aprotinin EDTA and thrombin to
prevent activation in vitro. Use a two-tube method of draining blood.
2. Draw the specimen in a prechilled tube and place immediately on ice.
3. Place the specimen in a biohazard bag. Clean venipuncture and gentle handling of specimen are required. The
specimen must be transported to the lab within 30 minutes.
Clinical Implications
1. Increased FPA occurs in:
a. DIC
b. Leukemia of various types
c. Venous thrombosis and pulmonary embolus
d. Myocardial infarction
e. Postoperative patients
f. Patients with widespread solid tumors, malignancies
2. Decreased FPA occurs in:
a. Clinical remission of leukemia achieved with chemotherapy
b. Therapeutic heparinization
Interfering Factors
1. A traumatic venous puncture may result in falsely increased levels.
2. The biologic half-life (stable for 2 hours or more) imposes limitations on the interpretation of a negative FPA test.

Clinical Alert
DIC occurs commonly in association with death of tumor cells in acute promyelocytic leukemia. For this reason,
heparin is used prophylactically and in association with the initiation of chemotherapy for promyelocytic leukemia. DIC
occurs less commonly during the treatment of acute myelomonocytic leukemia and acute lymphocyte leukemia.
Evidence of DIC should be sought in every patient with leukemia before initiation of treatment.
Interventions
Patient Preparation
1. Explain test purpose and procedure.
2. Avoid prolonged use of tourniquet.
3. See Chapter 1 guidelines for safe, effective, informed pretest care.
Patient Aftercare
1. Interpret test outcome and monitor appropriately for DIC and thrombosis.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .
3. Resume normal activities.
Prothrombin Fragment (F1 + 2)
The prothrombin F1 + 2 fragment is liberated from the prothrombin molecule when it is activated by factor Xa to form
thrombin. Thrombin may be rapidly inactivated by antithrombin III. The F1 + 2 fragment, however, has a half-life of about
1.5 hours, making it a useful marker for activated coagulation.
Prothrombin F1 + 2 is used to detect activation of the coagulation system before actual thrombosis occurs. It is used to
identify patients with low-grade intravascular coagulation (DIC) and to judge the effectiveness of oral anticoagulant
therapy. F1 + 2 levels may assist in the study of the hypercoagulable states and in the assessment of thrombotic risk.
Reference Values
Normal 7.4–102.9 µg/L or 0.2–2.78 nmol/L Levels rise slightly with age over 45 years.
Procedure
1. Draw a 5-mL sample of venous blood into a blue-topped (sodium citrate anticoagulant) Vacutainer.
2. Use the two-tube technique. (Some methods may use lithium heparin.)
Clinical Implications Increased prothrombin F1 + 2 is found in:
1.
2.
3.
4.
5.
6.

DIC (early)
Congenital deficiencies of antithrombin III
Congenital deficiencies of protein S and protein C
Leukemias
Severe liver disease
Post–myocardial infarction

NOTE
Failure to achieve a reduction in prothrombin F1 + 2 levels during oral anticoagulant therapy, despite an adequately
prolonged PT, suggests inadequate anticoagulation.
Interfering Factors
1. Levels will be high in the immediate postoperative period.
2. Decreased with oral anticoagulants (Coumadin)
3. Decreased in patients treated with AT-III
Interventions
Pretest Patient Preparation
1. Explain test purpose and procedure.
2. Avoid prolonged use of tourniquet.
3. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome and monitor appropriately for DIC and thrombosis.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .
3. Resume normal activities.
Fibrin Monomers (Protamine Sulfate Test; Fibrin Split Products)
A positive test result reflects the presence of fibrin monomers, indicative of thrombin activity and consistent with a
diagnosis of intravascular coagulation. A negative result does not mean that intravascular coagulation is not present. A

positive result may also be seen in some cases of severe liver disease and in inflammatory disorders caused by
accumulation of products of coagulation in the circulation.
The detection of fibrin monomers and early-stage FSPs in plasma is useful in the diagnosis of DIC. Heparin therapy does
not interfere with this test.
Reference Values
Normal Negative; no fibrin monomer present
Procedure
1. Obtain a 5-mL venous blood sample anticoagulated with sodium citrate (blue-topped tube). The two-tube technique
is used.
2. Place the specimen on ice and transport to the laboratory. The test must be performed within 1 hour after collection.
Clinical Implications
1. A positive test is indicative of DIC.
2. Patients with deep vein thrombosis occasionally have positive results.
3. The test may be positive in severe liver disease or metastatic cancer.
Interfering Factors False-positive results may occur in the following situations:
1. Traumatic venipuncture
2. During or immediately before menstruation
3. During streptokinase therapy (thrombolytic therapy)
Interventions
Pretest Patient Preparation
1. Explain test purpose and procedure. If possible, drain blood before heparin therapy is started.
2. Avoid prolonged use of tourniquet.
3. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome and monitor appropriately for DIC and thrombosis.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .
3. Resume normal activities.
Fibrinogen
Fibrinogen is a complex protein (polypeptide) that, with enzyme action, is converted to fibrin. The fibrin, along with
platelets, forms the network for the common blood clot. Although it is of primary importance as a coagulation protein,
fibrinogen is also an acute-phase protein reactant. It is increased in diseases involving tissue damage or inflammation.
This test is done to investigate abnormal PT, APTT, and TT and to screen for DIC and fibrin-fibrinogenolysis. It is part of
a coagulation panel.
Reference Values
Normal 200–400 mg/dL or 2.0–4.0 g/L
Procedure
1. Obtain a 5-mL venous blood sample using the two-tube technique with a collection tube containing sodium citrate.
2. Place the specimen in a biohazard bag.
Clinical Implications
1. Increased fibrinogen values occur in:
a. Inflammation and infections (rheumatoid arthritis, pneumonia, tuberculosis, streptomycin)
b. Acute myocardial infarction
c. Nephrotic syndrome
d. Cancer, multiple myeloma, Hodgkin's disease
e. Pregnancy, eclampsia
f. Various cerebral accidents and diseases
2. Decreased fibrinogen values occur in:
a. Liver disease
b. DIC (secondary fibrinolysis)
c. Cancer
d. Primary fibrinolysis
e. Hereditary and congenital hypofibrinogenemia
f. Dysfibrinogenemia
Interfering Factors

1.
2.
3.
4.
5.

High levels of heparin interfere with test results.
High levels of FSP and FDP cause low fibrinogen values.
Oral contraceptives cause high fibrinogen values.
Elevated AT-III may cause decreased fibrinogen.
See Appendix J for other drugs that affect test outcomes.

Clinical Alert
<100 mg/dL or 1.0 g/L—possible panic value, notify physician
1. Values <50 mg/dL or <0.5 g/L can result in hemorrhage after traumatic surgery.
2. Values >700 mg/dL or >7.0 g/L constitute a significant risk for both coronary artery and cerebrovascular disease.
Interventions
Pretest Patient Preparation
1. Explain test purpose and procedure.
2. Have the patient avoid aggressive muscular exercise before the test.
3. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome and monitor appropriately for DIC and response to treatment. If fibrinogen is low,
cryoprecipitate is the preferred product for therapeutic replacement.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .
Protein C (PC Antigen)
Protein C, a vitamin K–dependent protein that prevents thrombosis, is produced in the liver and circulated in the plasma.
It functions as an anticoagulant by inactivating factors V and VIII. Protein C is also a profibrinolytic agent (ie, it enhances
fibrinolysis). The protein C mechanism therefore functions to prevent extension of intravascular thrombi. This test is used
for evaluation of patients suspected of having congenital protein C deficiency. Resistance to protein C is caused by an
inherited defect in the factor V gene (factor V Leiden) and causes significant risk for thrombosis. It is the underlying
defect in up to 60% of patients with unexplained thrombosis and is the most common cause of pathologic thrombosis. If
functional protein C is abnormal, a protein C resistance test should be performed.
This test evaluates patients with severe thrombosis and those with an increased risk or predisposition to thrombosis.
Patients with partial protein C or partial protein S deficiency (heterozygotes) may experience venous thrombotic
episodes, usually in early adult years. There may be deep vein thromboses, episodes of thrombophlebitis or pulmonary
emboli (or both), and manifestations of a hypercoagulable state. Patients who are heterozygous may have type I protein
C deficiency, with decreased protein C antigen, or type II deficiency, with normal protein C antigen levels but decreased
functional activity.

NOTE
The protein S level should always be determined when a protein C test is ordered.

NOTE
Protein C resistance (factor V Leiden) should be tested in all patients with abnormal protein C activity.
Reference Values
Normal Qualitative: 70%–150% or 0.70–1.50 of increased functional activity Quantitative: 60%–125% or 0.60–1.25 of
normal PC antigen
Procedure
1. Anticoagulate a 5-mL venous blood sample with sodium citrate (blue-topped tube). The two-tube method is used.
2. Cap the specimen and place on ice.
Clinical Implications
1. Decreased protein C is associated with:
a. Severe thrombotic complications in the neonatal period (neonatal purpura fulminans)
b. Increased risk for venous thrombotic episodes
c. Warfarin (Coumadin)-induced skin necroses (pathognomonic for protein C deficiency)
d. DIC, especially when it occurs with cancer (presumably owing to consumption by cofactor
thrombin-thrombomodulin catalyst activities)
e. Thrombophlebitis and pulmonary embolism, especially in early adult years
f. Other acquired causes of protein C deficiency include:
1. Liver disease
2. Acute respiratory distress syndrome
3. L-Asparaginase therapy
4. Malignancies

5. Vitamin K deficiency
2. A deficiency of protein C may also be congenital (35%–58%).

Clinical Alert
Homozygous protein C–deficient patients have absent or almost absent protein C antigen and usually succumb in
infancy with the picture of purpura fulminans neonatalis, including lower extremity skin ecchymoses, anemia, fever, and
shock.
Interfering Factors
1.
2.
3.
4.
5.
6.

Decreased protein C is found in the postoperative state.
Pregnancy or use of oral contraceptives decreases protein C.
A transient drop in protein C occurs with a high loading dose of warfarin (Coumadin).
Protein C decreases with age.
High doses of heparin decrease protein C.
Lipemic serum may interfere with the assay.

Interventions
Pretest Patient Care
1. Explain test purpose and procedure. Patient should be fasting.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome and monitor appropriately for thrombosis. In the case of a protein C deficiency, educate the
patient concerning the symptoms and implications of the disease. The risk factors include obesity, oral
contraceptives, varicose veins, infection, trauma, surgery, pregnancy, immobility, and congestive heart failure.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .
Protein S
Both protein S and protein C are dependent on vitamin K for their production and function. A deficiency of either one is
associated with a tendency toward thrombosis. Protein S serves as a cofactor to enhance the anticoagulant effects of
activated protein C. Slightly more than half of protein S is complexed with C4 binding protein and is inactive. Activated
protein C in the presence of protein S rapidly inactivates factors V and VIII.
This test is done to differentiate acquired from congenital protein S deficiency. Congenital deficiency of protein S is
associated with a high risk for thromboembolism. Acquired deficiency of protein S can be seen in various autoimmune
disorders and inflammatory states owing to elevation of C4-binding protein. This protein forms an inactive complex with
protein S. C4-binding protein levels should be determined in all patients who demonstrate a reduced level of protein S.
Reference Values
Normal Males: 60%–130% or 0.60–1.30 of normal activity Females: 50%–120% or 0.50–1.20 of normal activity
Newborns: 15%–50% or 0.15–0.50 of normal activity
Procedure
1. Anticoagulate a 5-mL venous blood sample with sodium citrate (blue-topped tube). The two-tube method is used.
2. Keep the specimen capped and on ice. Place in biohazard bag and take to laboratory immediately.
Clinical Implications
1. Decreased values are associated with protein S deficiency. Familial protein S deficiency is associated with
recurrent thrombosis. Abnormal plasma distribution of protein S occurs in functional protein S deficiency. In type I,
free protein S is decreased, although the level of total protein may be normal; in type II, total protein is markedly
reduced.
2. Hypercoagulable-state acquired protein S deficiency is found in:
a. Diabetic nephropathy
b. Chronic renal failure caused by hypertension
c. Cerebral venous thrombosis
d. Coumarin-induced skin necrosis
e. DIC
f. Thrombotic thrombocytopenia purpura
g. Acute inflammation
Interfering Factors The following factors cause decreased protein S:
1.
2.
3.
4.
5.

Heparin therapy or specimen contaminated with heparin
Patient on unstable warfarin (Coumadin should be discontinued for 30 days for a true protein S determination)
Pregnancy
Contraceptives (oral)
First month of life

6. L-Asparaginase therapy

NOTE
This test is not useful in diagnosing DIC.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome and monitor appropriately for thrombotic tendency.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .
Antithrombin III (AT-III; Heparin Cofactor Activity)
AT-III inhibits the activity of activated factors XII, XI, IX, and X as well as factor II. AT-III is the main physiologic inhibitor
of activated factor X, on which it appears to exert its most critical effect. AT-III is a “heparin cofactor.” Heparin interacts
with AT-III and thrombin, increasing the rate of thrombin neutralization (inhibition) but decreasing the total quantity of
thrombin inhibited.
This test detects a decreased level of antithrombin that is indicative of thrombotic tendency. Only the test of functional
activity gives a direct clue to thrombotic tendency. In some families, several members may have a combination of
recurrent thromboembolism and reduced plasma antithrombin (30%–60%). A significant number of patients with
mesenteric venous thrombosis have AT-III deficiency. It has been recommended that patients with such thrombotic
disease be screened for AT-III levels to identify those patients who may benefit from coumarin anticoagulant prophylaxis
rather than heparin therapy.
Reference Values
Normal Functional assay Infants (1–30 days): 26%–61% or 0.26–0.61 (premature); 44%–76% or 0.44–0.76 (full-term)
Adults and infants older than 6 months: 80%–120% or 0.80–1.20 Immunologic assay Adults and infants older than 6
months: 17–30 mg/dL or 170–300 mg/L
Procedure
1. Anticoagulate a venous blood sample (5 mL) with sodium citrate. Mix gently.
2. Use the two-tube method.
3. Place the sample on ice and transport to laboratory immediately.
Clinical Implications
1. Increased AT-III values are associated with:
a. Acute hepatitis
b. Renal transplantation
c. Inflammation, patients with increased ESR
d. Menstruation
e. Use of warfarin (Coumadin) anticoagulant
f. Hyperglobulinemia
2. Decreased AT-III values are associated with:
a. Congenital deficiency (hereditary)
b. Liver transplantation and partial liver removal, cirrhosis, nephrotic syndrome, liver failure
c. DIC, fibrinolytic disorders (not diagnostically useful)
d. Acute myocardial infarction
e. Active thrombotic disease (deep vein thrombosis), thrombophlebitis
f. Carcinoma, trauma, severe inflammations
g. Pulmonary embolism
h. Heparin failure (low levels of AT-III exhibit heparin resistance)
i. Protein-wasting diseases
Interfering Factors
1.
2.
3.
4.
5.

Antithrombin decreases after 3 days of heparin therapy.
Use of oral contraceptives interferes with the test (decreased values).
Results are unreliable in the last trimester of pregnancy and in the early postpartum period.
Decreased after surgery, prolonged bed rest.
Decreased in L-asparaginase therapy.

Interventions
Pretest Patient Care
1. Explain test purpose and procedure.

2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome and monitor appropriately for thrombotic tendency.
2. If patient has decreased levels of AT-III, coumarin anticoagulant would be used as a prophylaxis.
3. See Chapter 1 guidelines for safe, effective, informed posttest care .
BIBLIOGRAPHY
Bick R, et al: Blood protein defects associated with thrombosis. Clin Lab Med 15(1), 1995
Bick R: Laboratory evaluation of platelet dysfunction, thrombosis and hemostasis for the clinical laboratory. Clin Lab Med 15(1), 1995
Dahlback B: Resistance to activated protein C as risk factor for thrombosis: Molecular mechanisms, laboratory investigation, and clinical
management. Semin Hematol 34(3): 217–234, 1997
Freeman J, Rodgers BA: Lupus: A Patient Care Guide for Nurses and Other Health Professionals. Bethesda, MD, National Institutes of Health,
National Institute of Arthritis and Musculoskeletal and Skin Diseases, 1999
Goroll AH, May LA, Mulley GA: Primary Care Medicine: Office Evaluation and Management of the Adult Patient, 4th ed. Philadelphia,
Lippincott Williams & Wilkins, 2000
Handin RI, Lux SE, Stossel TP: Blood: Principles and Practice of Hematology, 2nd ed., Philadelphia, Lippincott Williams & Wilkins, 2002
Henry J, et al: Clinical Diagnosis and Management by Laboratory Methods, 20th ed. Philadelphia, WB Saunders, 2001
Jacobs D, et al: Laboratory Test Handbook, 4th ed. Hudson, OH, Lexi-Comp, 1996
Kjeldsberg C: Practical Diagnosis of Hematologic Disorders, revised ed. Chicago, ASCP Press, 1991
Koepke J: Is ESR useful? Med Lab Observ 29(1): 1997
Krenzischek DA, Tanseco FV: Comparative study of bedside and laboratory measurements of hemoglobin. Am J Crit Care 5(6): 427, 1996
Leavelle D: Interpretive Data for Diagnostic Laboratory Tests. Rochester, MN, Mayo Clinic Laboratories, 2001
Lee GR, Foerster J, Lukens J, et al: Wintrobe's Clinical Hematology, 10th ed., Philadelphia, Lippincott Williams & Wilkins, 1999
Looker AC, Dallman PR, Carroll MD, et al: Prevalence of iron deficiency in the United States. JAMA 277: 973, 1997
Samama M: Laboratory monitoring of unfractionated heparin treatment, thrombosis and hemostasis for the clinical laboratory. Clin Lab Med
15(1), 1995
Speicher CE: The Right Test: A Physician's Guide to Laboratory Medicine, 3rd ed. Philadelphia, WB Saunders, 1998
Stamatoyannopoulos G, Majerus PW, Perlmutter RM, Varmus H: The Molecular Basis of Blood Diseases, 3rd ed., Philadelphia, WB Saunders,
2001
Statland B: Tips from clinical experts. Med Lab Observ 29(1): 1997
Steine-Martin EA, Lotspeich-Steininger CA, Koepke JA: Clinical Hematology: Principles, Procedures, Correlations. Philadelphia,
Lippincott-Raven, 1997
Tietz N: Clinical Guide to Laboratory Tests, 3rd ed. Philadelphia, WB Saunders, 1995
Tkachuk D, Hirschmann JV, McArthur JR: Atlas of Clinical Hematology, Philadelphia, WB Saunders, 2002
Turgeon ML: Clinical Hematology Theory & Procedures, 3rd ed. Philadelphia, Lippincott Williams & Wilkins, 1999
Wallach J: Interpretation of Diagnostic Tests, 7th ed. Philadelphia, Lippincott Williams & Wilkins, 2000

3 Urine Studies
A Manual of Laboratory and Diagnostic Tests

3
Urine Studies
OVERVIEW OF URINE STUDIES
Urine Formation
Urine Constituents
Types of Urine Specimens
URINE TESTING
Chart 3.1 Urinary System and Related Tests
Laboratory Testing for Routine Urinalysis
Dipstick Testing
NOTE
COLLECTION OF URINE SPECIMENS
Single, Random Urine Specimen
Long-Term, Timed Urine Specimen (2-Hour, 24-Hour)
ROUTINE URINALYSIS (UA) AND RELATED TESTS
Urine Volume
Urine Specific Gravity (SG)
Urine Osmolality
Urine Appearance
Urine Color
Urine Odor
Urine pH
Urine Blood or Hemoglobin (Hb)
Urine Protein (Albumin), Qualitative and 24-Hour
Microalbuminuria/Albumin (24-Hour Urine)
Urine ß2-Microglobulin
Urine Glucose (Sugar)
Urine Ketones (Acetone; Ketone Bodies)
Urine Nitrite (Bacteria)
Urine Leukocyte Esterase
Urine Bilirubin
Urine Urobilinogen, Random and Timed
MICROSCOPIC EXAMINATION OF URINE SEDIMENT
Clinical Alert
Urine Red Blood Cells and Red Blood Cell Casts
Urine White Blood Cells and White Blood Cell Casts
Urine Epithelial Cells and Epithelial Casts
Urine Hyaline Casts
Urine Granular Casts
Urine Waxy Casts or Broad Casts (Renal Failure Casts) and Fatty Casts
Urine Crystals
Urine Shreds
URINE CHEMISTRY
Urine Pregnancy Test; Human Chorionic Gonadotropin (hCG) Test
Urine Estrogen, Total and Fractions (Estradiol [E2] and Estriol [E3]), 24-Hour Urine and Total Estrogen—Blood
URINE DRUG INVESTIGATION SPECIMENS
Clinical Alert
Chart 3.2 Common Urine Drug Tests*
Clinical Alert
Witnessed Urine Sampling for Suspected Substance Abuse
TIMED URINE TESTS
Urine Chloride (Cl), Quantitative (24-Hour)
Urine Sodium (Na), Quantitative (24-Hour)
Urine Potassium (K), Quantitative (24-Hour) and Random
Urine Uric Acid, Quantitative (24-Hour)
Urine Calcium (Ca), Quantitative (24-Hour)
Urine Magnesium (Mg), Quantitative (24-Hour)
Urine Oxalate, Quantitative (24-Hour)
Urine Pregnanediol (24-Hour)
NOTE
Urine Pregnanetriol (24-Hour)
Urine 5-Hydroxyindoleacetic Acid (5-HIAA) (24-Hour)
Urine Vanillylmandelic Acid (VMA); Catecholamines (24-Hour)
Urine Porphyrins and Porphobilinogens (24-Hour and Random); ?-Aminolevulinic Acid (ALA, ?-ALA)
Urine Amylase Excretion and Clearance (Random, Timed Urine, and Blood)
Phenylketonuria (PKU); Urine Phenylalanine (Random Urine and Blood)
D-Xylose Absorption (Timed Urine and Blood)
Urine Creatinine; Creatinine Clearance (Timed Urine and Blood)
Urine Cystine (Random and 24-Hour)
Urine Hydroxyproline (Timed Urine and Blood)
NOTE
Urine Lysozyme (Random, 24-Hour Urine, and Blood)
Urine Amino Acids, Total and Fractions (Random, 24-Hour Urine, and Blood)
BIBLIOGRAPHY

OVERVIEW OF URINE STUDIES
Urine Formation
Urine is continuously formed by the kidneys. It is actually an ultrafiltrate of plasma from which glucose, amino acids,
water, and other substances essential to body metabolism have been reabsorbed. The physiologic process by which
approximately 170,000 mL of filtered plasma is converted to the average daily urine output of 1200 mL is complex.
Urine formation takes place in the kidneys, two fist-sized organs located outside the peritoneal cavity on each side of the
spine, at about the level of the last thoracic and first two lumbar vertebrae. The kidneys, together with the skin and the
respiratory system, are the chief excretory organs of the body. Each kidney is a highly discriminatory organ that
maintains the internal environment of the body by selective secretion or reabsorption of various substances according to
specific body needs.
The main functional unit of the kidney is the nephron. There are about 1 to 1.5 million nephrons per kidney, each
composed of two main parts: a glomerulus, which is essentially a filtering system, and a tubule through which the filtered
liquid passes. Each glomerulus consists of a capillary network surrounded by a membrane called Bowman's capsule,
which continues on to form the beginning of the renal tubule. The kidney's ability to clear waste products selectively from
the blood while maintaining the essential water and electrolyte balances in the body is controlled in the nephron by renal
blood flow, glomerular filtration, and tubular reabsorption and secretion.
Blood is supplied to the kidney by the renal artery and enters the nephron through the afferent arteriole. It flows through
the glomerulus and into the efferent arteriole. The varying size of these arterioles creates the hydrostatic pressure
difference necessary for glomerular filtration and serves to maintain glomerular capillary pressure and consistent renal
blood flow within the glomerulus. (The smaller size of the efferent arteriole produces an increase in the glomerular
capillary pressure, which aids in urine formation.)
As the filtrate passes along the tubule, more solutes are added by excretion from the capillary blood and secretions from
the tubular epithelial cells. Essential solutes and water pass back into the blood through the mechanism of tubular
reabsorption. Finally, urine concentration and dilution occur in the renal medulla. The kidney has the remarkable ability to
dilute or concentrate urine, according to the needs of the individual, and to regulate sodium excretion. Blood chemistry,
blood pressure, fluid balance, and nutrient intake, together with the general state of health, are key elements in this
entire metabolic process.
Urine Constituents
In general, urine consists of urea and other organic and inorganic chemicals dissolved in water. Considerable variations
in the concentrations of these substances can occur as a result of the influence of factors such as dietary intake, physical
activity, body metabolism, endocrine function, and even body position. Urea, a metabolic waste product produced in the
liver from the breakdown of protein and amino acids, accounts for almost half of the total dissolved solids in urine. Other
organic substances include primarily creatinine and uric acid. The major inorganic solid dissolved in urine is chloride,
followed by sodium and potassium. Small or trace amounts of many additional inorganic chemicals are also present in
urine. The concentrations of these inorganic compounds are greatly influenced by dietary intake, making it difficult to
establish normal levels. Other substances found in urine include hormones, vitamins, and medications. Although they are
not a part of the original plasma filtrate, the urine may also contain formed elements such as cells, casts, crystals, mucus,
and bacteria. Increased amounts of these formed elements are often indicative of disease.
Types of Urine Specimens
During the course of 24 hours, the composition and concentration of urine changes continuously. Urine concentration
varies according to water intake and pretest activities. To obtain a specimen that is truly representative of a patient's
metabolic state, it is often necessary to regulate certain aspects of specimen collection, such as time of collection, length
of collection period, patient's dietary and medicinal intake, and method of collection. It is important to instruct patients
when special collection procedures must be followed. See Appendix A: Standard Precautions, Appendix B: Latex
Precautions, and Appendix E: Guidelines for Specimen Transport for additional guidelines.

URINE TESTING
Urinalysis (UA) is an essential procedure for patients undergoing hospital admission or physical examination. It is a
useful indicator of a healthy or diseased state and has remained an integral part of the patient examination. Two unique
characteristics of urine specimens can account for this continued popularity:
1. Urine is a readily available and easily collected specimen.
2. Urine contains information about many of the body's major metabolic functions, and this information can be
obtained by simple laboratory tests.
These characteristics fit in well with the current trends toward preventive medicine and lower medical costs. By offering
an inexpensive way to test large numbers of people, not only for renal disease but also for the asymptomatic beginnings
of conditions such as diabetes mellitus and liver disease, the UA can be a valuable metabolic screening procedure.
Should it be necessary to determine whether a particular fluid is actually urine, the specimen can be tested for its urea
and creatinine content. Inasmuch as both of these substances are present in much higher concentrations in urine than in

other body fluids, the demonstration of a high urea and creatinine content can identify a fluid as urine ( Chart 3.1).

Chart 3.1 Urinary System and Related Tests
Organs and Function
The kidneys, ureter, bladder, and urethra compose the urinary system. Kidneys must be able to excrete dietary and
waste products (not eliminated by other organs) through the urine. Urine is formed within the functional unit of the
kidneys, the nephron, which consists of glomeruli and tubules.
KIDNEY GLOMERULUS
Formation of filtrate
Filtration
KIDNEY TUBULE
Secretion of waste products
Reabsorption of waste products needed by the body
Reabsorption of water, sodium chloride, bicarbonates, potassium, and calcium, among others
KIDNEY: PELVIS, URETERS, AND BLADDER
Excretion and storage of formed urine
Main urine constituents: water, urea, uric acid, creatinine, sodium, potassium, chloride, calcium, magnesium,
phosphates, sulfates, and ammonia
Examples of Selective Filtration, Reabsorption, and Excretion by the Urinary System

Constituent Filtered (g/24 h) Reabsorbed (g/24 h) Excreted (g/24 h)
Sodium
540
537
3.3
Chloride
630
625
5.3
Bicarbonate
300
300
0.3
Potassium
28
24
3.9
Glucose
140
140
0.0
Urea
53
28
25
Creatinine
1.4
0.0
1.4
Uric acid
8.5
7.7
0.8

Laboratory Testing for Routine Urinalysis
First, the physical characteristics of the urine are noted and recorded. Second, a series of chemical tests is run. A
chemically impregnated dipstick can be used for many of these tests. Standardized results can be obtained by
processing the urine-touched dipstick through special automated instruments. Third, the urine sediment is examined
under the microscope to identify the components of the urinary sediment.
Dipstick Testing
Although laboratory facilities allow for a wide range of urine tests, some types of tablet, tape, and dipstick tests are
available for UA outside the laboratory setting. They can be used and read directly by patients and clinicians.
Similar in appearance to pieces of blotter paper on a plastic strip, dipsticks actually function as miniature laboratories.
Chemically impregnated reagent strips (UA Chemstrip Screen) provide quick determinations of pH, protein, glucose,
ketones, bilirubin, hemoglobin (blood), nitrite, leukocyte esterase, urobilinogen, and specific gravity. The dipstick is
impregnated with chemicals that react with specific substances in the urine to produce color-coded visual results. The
depth of color produced relates to the concentration of the substance in the urine. Color controls are provided against
which the actual color produced by the urine sample can be compared. The reaction times of the impregnated chemicals
are standardized for each category of dipstick; it is vital that color changes be matched to the control chart at the correct
elapsed time after each stick is dipped into the urine specimen. Instructions that accompany each type of dipstick outline
the procedure. When more than one type of test is incorporated on a single stick (eg, pH, protein, and glucose), the
chemical reagents for each test are separated by a water-impermeable barrier made of plastic so that results do not
become altered ( Table 3.1). An example of a form used to record dipstick (UA Chemstrip Screen) testing results is
shown on the following page.

Table 3.1 Urine Testing by Dipstick/Reagent Strip
Possible Reaction Interference
Measurement False-Positive

False-Negative

Correlations with
Other Tests

pH

None

Runover from the protein pad may lower

Protein

Highly alkaline urine, ammonium
compounds (antiseptics),
detergents

High salt concentration

Glucose

Peroxide, oxidizing detergents

Ketones
Blood

Levodopa, phenylketones
Oxidizing agents, vegetable and
bacterial peroxidases

Bilirubin
Urobilinogen

Lodine, pigmented urine, indican
Ehrlich-reactive compounds
(Multistix), medication color
Pigmented urine on automated
readers

Ascorbic acid, 5-HIAA, homogentisic acid,
aspirin, levodopa, ketones, high specific gravity
with low pH
None
Glucose
Ascorbic acid, nitrite, protein pH < 5.0, high
Protein
specific gravity, captopril
Microscopic
examination
Ascorbic acid, nitrite
Urobilinogen
Nitrite, formalin
Bilirubin

Nitrite

Ascorbic acid, high specific gravity

Leukocytes

Oxidizing detergents

Glucose, protein, high specific gravity, oxalic
acid, gentamycin, tetracycline, cephalexin,
cephalothin

Specific
gravity

Protein

Alkaline urine

Nitrite
Leukocytes
Microscopic
examination
Blood
Nitrite
Leukocytes
Microscopic
examination
Ketones

Protein
Leukocytes
Microscopic
examination
Protein
Nitrite
Microscopic
examination
None

In addition to dipsticks, reagent strips, tablets, and treated slides for special determinations such as bacteria,
phenylketonuria (PKU), mucopolysaccharides, salicylate, and cystinuria are available for urine analysis.

Figure. No caption available.

NOTE
Tablets are becoming obsolete but are still used for certain tests, such as glucose and reducing agents.
Procedure
1. Use a fresh urine sample within 1 hour of collection or a sample that has been refrigerated; bring to room
temperature and mix specimen.
2. Read or review directions for use of the reagent. Periodically check for changes in procedure.
3. Dip a reagent strip into well-mixed urine, then remove it, blot, and compare each reagent area on the dipstick with
the corresponding color control chart within the established time frame. Correlate color comparisons as closely as
possible using good lighting.
Interfering Factors
1. If the dipstick is kept in the urine sample too long, the impregnated chemicals in the strip might be dissolved and
could produce inaccurate readings and values.
2. If the reagent chemicals on the impregnated pad become mixed, the readings will be inaccurate. To avoid this, blot
off excess urine after withdrawing the dipstick from the sample.

Clinical Alert
1. Precise timing is essential. If the test is not timed correctly, color changes may produce invalid or false results.
2. When not in use, the container of dipsticks should be kept tightly closed and stored in a cool, dry environment. If
the reagents absorb moisture from the air before they are used, they will not produce accurate results. A
desiccant comes with the reagents and should be kept in the container.
3. Quality control protocols must be followed:
a. The expiration date must be honored even if there is no detectable deterioration of strips.
b. Bottles must be discarded 6 months after opening, regardless of expiration date.
c. Known positive and negative (abnormal and normal) controls must be run for each new bottle of reagent strips
when it is opened and whenever there is a question of deterioration.

COLLECTION OF URINE SPECIMENS
Standard UA specimens can be collected any time, whereas first morning, fasting, and timed specimens require
collection at specific times of day. Patient preparation and education needs vary according to the type of specimen
required ( Table 3.2) and the patient's ability to cooperate with specimen collection. Clear instructions and assessment of
the patient's understanding of the process are key to a successful outcome. Assess the patient's usual urinating patterns
and encourage fluid intake (unless contraindicated). Provide verbal and written directions for self-collection of
specimens. Assess for presence of interfering factors: failure to follow collection instructions, inadequate fluid intake,
certain medications, and patient use of illegal drugs may affect test results. Certain foods, or any type of food
consumption in some instances, may also affect test results.

Table 3.2 Collection of Urine Specimens *
Type of Specimen
FIRST MORNING SPECIMEN
Most concentrated
Bladder-incubated
Best for nitrate, protein, pregnancy tests; microscopic
examination; routine screening
RANDOM SPECIMEN
Most convenient
Collected any time
Good for chemical screening, routine screening, microscopic
examination
CLEAN-CATCH (MIDSTREAM)
Used for random collection and bacterial culture
SECOND (DOUBLE-VOIDED) SPECIMEN
The first morning specimen is discarded; the second specimen
is collected and tested

POSTPRANDIAL
Used for glucose determination, diabetic monitoring
TIMED
Requires collection at certain time
TIMED 2-HOUR VOLUME
Used for urobilinogen determination
TIMED 24-HOUR VOLUME
Necessary for accurate quantitative results
Chemical testing
CATHETER SPECIMEN
Clamp catheter 15 to 30 minutes before collection
Cleanse sample port with alcohol
Insert needle into sample port; after aspirating sample, transfer
to specimen container
ALERT: Unclamp catheter
SUPRAPUBIC ASPIRATION
Sterile bladder urine
*Place urine specimens in a biohazard bag.

Characteristics
Free of dietary influences
Formed elements may disintegrate if pH is high and/or
specific gravity is low

Most common

Minimizes bacterial counts
Diabetic monitoring
Reflects blood glucose/usually fasting; less
concentrated urine
Formed elements remain intact
Accurately reflects components
Collected 2 hours after a meal
Total specimen must be collected
All urine saved for 2-hour period
All urine saved for 24-hour period

Bacterial culture

Bacterial culture cytology

Single, Random Urine Specimen
This is the most commonly requested specimen. Because the composition of urine changes over the course of the day,
the time of day when the specimen is collected may influence the findings. The first voided morning specimen is
particularly valuable because it is usually more concentrated and therefore more likely to reveal abnormalities as well as

the presence of formed substances. It is also relatively free of dietary influences and of changes caused by physical
activity because the specimen is collected after a period of fasting and rest.
Procedure
1. Instruct the patient to void directly into a clean, dry container or bedpan. Transfer the specimen directly into an
appropriate container. Disposable containers are recommended. Women should always have a clean-catch
specimen if a microscopic examination is ordered (see Chap. 7).
2. Collect specimens from infants and young children into a disposable collection apparatus consisting of a plastic bag
with an adhesive backing around the opening that can be fastened to the perineal area or around the penis to
permit voiding directly into the bag. The specimen bag is carefully removed, and the urine is transferred to an
appropriate specimen container.
3. Cover all specimens tightly, label properly, and send immediately to the laboratory. Place the label on the cup, not
on the lid.
4. Obtain a clean specimen using the same procedure as for bacteriologic examination (see Chap. 7) if a urine
specimen is likely to be contaminated with drainage, vaginal discharge, or menstrual blood.
5. If a urine specimen is obtained from an indwelling catheter, it may be necessary to clamp off the catheter for about
15 to 30 minutes before obtaining the sample. Clean the specimen port (in the tubing) with antiseptic before
aspirating the urine sample with a needle and syringe.
6. Observe standard precautions when handling urine specimens (see Appendix A).
7. If the specimen cannot be delivered to the laboratory or tested within 1 hour, it should be refrigerated or have an
appropriate preservative added.
Interfering Factors
1. Feces, discharges, vaginal secretions, and menstrual blood will contaminate the urine specimen. A clean voided
specimen must be obtained.
2. If the specimen is not refrigerated within 1 hour of collection, the following changes in composition may occur:
a. Increased pH from the breakdown of urea to ammonia by urease-producing bacteria
b. Decreased glucose from glycolysis and bacterial utilization
c. Decreased ketones because of volatilization
d. Decreased bilirubin from exposure to light
e. Decreased urobilinogen as a result of its oxidation to urobilin
f. Increased nitrite from bacterial reduction of nitrate
g. Increased bacteria from bacterial reproduction
h. Increased turbidity caused by bacterial growth and possible precipitation of amorphous material
i. Disintegration of red blood cells (RBCs) and casts, particularly in dilute alkaline urine
j. Changes in color caused by oxidation or reduction of metabolites
Long-Term, Timed Urine Specimen (2-Hour, 24-Hour)
Some diseases or conditions require a second morning specimen or a 2-hour or 24-hour urine specimen to evaluate
kidney function accurately (see Table 3.2). Substances excreted by the kidney are not excreted at the same rate or in the
same amounts during different periods of the day and night; therefore, a random urine specimen might not give an
accurate picture of the processes taking place over a 24-hour period. For measurement of total urine protein, creatinine,
electrolytes, and so forth, more accurate information is obtained from a long-term specimen. All urine voided in a 24-hour
period is collected into a suitable receptacle; depending on the intended test, a preservative is added, the collection is
kept refrigerated, or both ( Table 3.3).

Table 3.3 24-Hour Collection: Standards for Timed Urine Specimen Collection
Test Element and Purpose

Preservative

Acid mucopolysaccharides inherited enzyme deficiency in
infants with mental retardation or failure to thrive

20 mL toluene (add at start of Refrigerate during
collection)
collection; include patient's
age
1 g boric acid per 100 mL
Refrigerate
urine
None
Refrigerate during
collection
25 mL of 50% acetic acid; for Refrigerate or ice; protect
children < 5 y, use 15 mL of
from light
50% acetic acid
None
Refrigerate during
collection
20 mL of 6N HNO 3 in a
Refrigerate during
collection
metal-free container
20 mL of 6N HNO 3 in a
Refrigerate during
collection
metal-free container

Aldosterone (cause of hypertension)
Amino acids, quantitative (aminoaciduria, screen for inborn
errors of metabolism and genetic abnormalities)
Aminolevulinic acid (porphyria and lead poisoning)

Amylase (differentiates acute pancreatitis from other
abdominal diseases)
Arsenic (arsenic poisoning—occupational exposure)
Cadmium (toxic levels, including occupational exposure)

Specimen Handling and
Storage

Calcium, quantitative Sulkowitch (hypercalciuria as in
hyperparathyroidism, hyperthyroidism, vitamin D toxicity,
Paget's disease, osteolytic diseases, and renal tubular
acidosis)
Catecholamine fractions, urinary free catecholamines
(measure adrenomedullary function, to diagnose
pheochromocytoma)
Chloride (electrolyte imbalance, dehydration, metabolic
alkalosis)
Chromium (toxic levels, including occupational exposure)

30 mL of 6N HCl

Refrigerate during
collection

25 mL of 50% acetic acid; for Refrigerate or freeze, pH
children < 5 y, use 15 mL of
1–3
50% acetic acid
None
Refrigerate during
collection
20 mL of 6N HNO 3 in a
Refrigerate
metal-free container
Citrate/citric acid (renal disease)
10 g boric acid
Refrigerate
Copper (Wilson's disease)
20 mL of 6N HNO 3 in a
Refrigerate during
collection
metal-free container
Cortisol, free (hydrocortisone levels in adrenal hormone
30 mL of 6N HCl
Refrigerate during
function)
collection
Creatinine (to evaluate disorders of kidney function)
None
Refrigerate during
collection
Creatinine clearance (measures kidney function, primarily
None
Refrigerate during
glomerular filtration)
collection
Cyclic adenosine monophosphate
None
Refrigerate during
collection; freeze a portion
after collection
Cystine, quantitative (to diagnose cystinuria, inherited
20 mL of toluene
Refrigerate during
disease characterized by bladder calculi)
collection, pH 2–3; if not
acidified—freeze
?-Aminolevulinic acid (porphyria and lead poisoning)
30 mL of 33% glacial acetic
Protect from light;
acid
refrigerate during collection
Electrolytes, sodium, potassium (electrolyte imbalance)
None, or 1.0 g boric acid
Refrigerate
Estriol, estradiol (menstrual and fertility problems, male
1.0 g boric acid
Refrigerate during
feminization characteristics, estrogen-producing tumors, and
collection
pregnancy)
Estrogens, total, nonpregnancy or third trimester (estrogen
1.0 g boric acid
Refrigerate during
levels for menstrual and fertility problems, pregnancy and
collection
estrogen-producing tumors)
Follicle-stimulating/luteinizing hormone (gonadotropic
1.0 g boric acid or none
Store frozen
hormones, FSH and LH to determine cause of gonadal
deficiency)
Glucose (glucosuria to screen, confirm, or monitor diabetes 1.0 g boric acid or NaF
Store in dark bottle
mellitus, rapid intestinal absorption)
Histamine (chronic myelogenous leukemia, carcinoids,
None
Refrigerate; freeze portion
polycythemia vera)
after collection
Homogentisic acid
None
Freeze portion after
collection
Homovanillic acid (to diagnose neuroblastoma,
15 mL of 50% acetate acid <5 Refrigerate during
pheochromocytoma, ganglioblastoma)
yrs of age, 25 mL of 50%
collection
acetic acid >5 years of age, to
maintain pH 2.0–4.0
17-Hydroxycorticosteroids (adrenal function by measuring
1.0 g boric acid
Refrigerate, pH 5–7; freeze
urine excretion of steroids to diagnose endocrine
portion after collection
disturbances of the adrenal androgens, Cushing's, Addison's,
and so forth)
5-Hydroxyindoleacetic acid, serotonin (carcinoid tumors)
15 mL of 50% acetate acid <5 Refrigerate during
5-HIAA
yrs of age, 25 mL of 50%
collection; freeze portion
acetic acid >5 years of age, to after collection
maintain pH 2.0–4.0
Hydroxyproline, free (measures the free hydroxyproline [less 10 mL 6N HCl per liter of
Refrigerate during
than 10% normally]; rapid growth and increased collagen
urine, maintain pH < 3
collection; store frozen
turnover)
Hydroxyproline, total 24-hour collection (bone collagen
10 mL 6N HCl per liter of
Refrigerate during
reabsorption and the degree of bone destruction from bone urine, maintain pH < 3
collection; use gelatin-free
tumors)
and low-collagen diet
Immunofixation electrophoresis (measures immune status
None
Refrigerate
and competence by identifying monoclonal and particle
protein band immunoglobulins)
? and ? chains quantitative, also in serum (monoclonal
None
Refrigerate
gammopathies, myeloma tumor burden)
17-Ketogenic steroids (Porter-Silber and Cushing's
1.0 g boric acid
Do not refrigerate
syndrome, adrenogenital syndrome)
17-Ketosteroid, fractions (adrenal and gonadal abnormalities) 1.0 g boric acid
Do not refrigerate
Lead (lead poisoning and chelation therapy)
20 mL of 6N HNO 3 in a
Refrigerate
metal-free container

Lipase (acute pancreatitis and to differentiate pancreatitis
from other abdominal disorders)
Lysozyme, muramidase (to differentiate acute myelogenous
or monocytic leukemia from acute lymphatic leukemia)
Magnesium (magnesium metabolism, electrolyte status, and
nephrolithiasis)
Manganese (toxicity, parenteral nutrition)

None

Refrigerate

None

Refrigerate

20 mL of 6N HCl in a
metal-free container
None

Refrigerate

Mercury (toxicity, industrial and dental overexposure;
inorganic mercury)
Metanephrine, total (assays of catecholamines and
vanillylmandelic acid; frequently to diagnose
pheochromocytoma)
Metanephrine, fractions (to diagnose and monitor
pheochromocytoma and ganglioneuroblastoma)
Metanephrine, total (pheochromocytoma, children with
neuroblastoma, ganglioneuroma)

20 mL of 6N HNO 3 in a
metal-free container
30 mL of 6N HCl

Refrigerate during
collection
Refrigerate; pH 2 with nitric
acid
pH 1–3

30 mL of 6N HCl, final pH < 3 Refrigerate; no caffeine
before or during testing
25 mL of 50% acetic acid; for Refrigerate; no caffeine
children <5 y, use 15 mL of
before or during testing
50% acetic acid; or 30 mL of
6N HCl
MHPG (3-methoxy-4-hydroxyphenylglycol) (to classify bipolar None
Refrigerate, ship frozen
manic depression for drug therapy)
Microalbumin, 24-hour (diabetic nephropathy)
None
Refrigerate
Osmolality, 24-hour (diabetes insipidus, primary polypepsia) None
Refrigerate
Oxalate (nephrolithiasis and inflammatory bowel diseases)
20 mL of 6N HCl
Refrigerate, pH 2–3
Phosphorous, 24-hour (renal losses; hyperparathyroidism
Acid-washed, detergent-free Refrigerate during
and hypoparathyroidism)
container
collection; acidify after
collection
Porphobilinogens
None
Refrigerate during
collection; freeze a portion;
protect from light
Porphyrins, quantitative (to diagnose porphyrias and lead
5 g sodium carbonate (do not Refrigerate; protect
poisoning)
use sodium bicarbonate)
specimen from light
Porphyrins (to diagnose porphyrias and lead poisoning)
None (preservative is added Refrigerate; protect
on receipt in laboratory)
specimen from light
Potassium, 24-hour (electrolyte imbalance, renal and adrenal None
Refrigerate during
disorders)
collection
Pregnanediol, 24-hour (measures ovarian and placental
Boric acid
Refrigerate during
function)
collection
Pregnanetriol (adrenogenital syndrome)
25 mL of 50% acetic acid; for Refrigerate during
children <5 y, use 15 mL of
collection; pH 4–4.5 after
50% acetic acid
receipt in laboratory
Protein electrophoresis, 24-hour
None
Refrigerate
Protein, total (proteinuria, differential diagnosis of renal
None
Refrigerate during
disease)
collection
Selenium (nutritional deficiency, industrial exposure)
None
Refrigerate; transport entire
specimen to laboratory
Sodium, 24-hour (electrolyte imbalance, acute renal failure, None
Refrigerate during
oliguria and hyponatremia, sodium excreted for diagnosis of
collection
renal and adrenal imbalances)
Substance abuse screen (specific drugs and alcohol involved None
Refrigerate or freeze
in substance abuse)
Thallium (thallium toxicity, occupational exposure)
None
Refrigerate
Thiocyanate (short-term nitroprusside therapy, cyanide
None
Refrigerate during
poisoning)
collection
Total protein (renal disease)
None
Refrigerate during
collection
Urea nitrogen, 24-hour (kidney function, hyperalimentation) 10 g boric acid
Refrigerate
Uric acid, 24-hour (uric acid metabolism in gout and renal
None
Refrigerate during
calculus formation)
collection
Urobilinogen (liver function and liver cell damage)
5 g sodium carbonate and 100 Refrigerate during
mL petroleum ether (do not
collection; protect specimen
use sodium bicarbonate)
from light; check with
laboratory
Vanillylmandelic acid, quantitative (adrenomedular
15 mL of 50% acetate acid <5 Refrigerate, pH 1–3; protect
pheochromocytoma, hypertension)
yrs of age, 25 mL of 50%
from light
acetic acid >5 years of age
Zinc (industrial exposure, toxicity, nutritional, acrodermatitis 20 mL 6N HNO 3 in a
Refrigerate
enteropathies)
metal-free container

Procedure

1. Ask the patient to void at the beginning of a 24-hour timed urine specimen collection (or any other timed specimen
collection). Discard this first specimen, and note the time.
2. Mark the time the test begins and the time the collection should end on the container. As a reminder, it may be
helpful to post a sign above the toilet (eg, “24-Hour Collection in Progress”), with the beginning and ending times
noted.
3. Collect all urine voided over the next 24 hours into a large container (usually glass or polyethylene), and label it
with the patient's name, the timeframe for collection, the test ordered, and other pertinent information. It is not
necessary to measure the volume of individual voidings, unless specifically ordered.
4. Ask the patient to void 24 hours after the first voiding, to conclude the collection. Add urine from this last voiding to
the specimen in the container.
5. Storage
a. Keep nonrefrigerated samples in a specified area or in the patient's bathroom.
b. Refrigerate the collection bottle immediately after the patient has voided or place it into an iced container if
refrigeration is necessary.

NOTE
Because the patient may not always be able to void on request, the last specimen should be obtained as closely as
possible to the stated end-time of the test.
Special Considerations
1. In a health care facility, responsibility for the collection of urine specimens should be specifically assigned.
2. When instructing a patient about 24-hour urine collections, make certain the patient understands that the bladder
must be emptied just before the 24-hour collection starts and that this preliminary specimen must be discarded;
then, all urine voided until the ending time is saved.
3. Do not predate and pretime requisitions for serial collections. It is difficult for some patients to void at specific times.
Instead, mark the actual times of collection on containers.
4. Documentation of the exact times at which the specimens are obtained is crucial to many urine tests.
5. Instruct the patient to urinate as near to the end of the collection period as possible.
6. When a preservative is added to the collection container (eg, HCl preservative in 24-hour urine collection for
vanillylmandelic acid [VMA]), the patient must take precautions against spilling the contents and receiving an acid
burn. Instructions regarding spillage need to be provided before the test begins.
7. The preservative used is determined by the urine substance to be tested for. The laboratory usually provides the
container and the proper preservative when the test is ordered. If in doubt, verify this with the laboratory personnel.
Interfering Factors
1. Failure of patient or attending personnel to follow the procedure is the most common source of error.
a. The patient should be given both verbal and written instructions. If the patient is unable to comprehend these
directions, a significant other should be instructed in the process.
b. If required, the proper preservative must be used.
2. Instruct the patient to use toilet paper after transferring the urine to the 24-hour collection container. Toilet paper
placed in the specimen decreases the actual amount of urine available and contaminates the specimen.
3. The presence of feces contaminates the specimen. Patients should void first and transfer the urine to the collection
receptacle before defecating.
4. If heavy menstrual flow or other discharges or secretions are present, the test may have to be postponed, or an
indwelling catheter may need to be inserted to keep the specimen free of contamination. In some cases, thorough
cleansing of the perineal or urethral area before voiding may be sufficient. If in doubt, communicate with laboratory
personnel and the patient's physician.
Interventions
Pretest Patient Preparation
Most 24-hour urine specimen collections start in the early morning at about 7:00 a.m. (0700). Instruct the patient to do the
following:
1. Empty the bladder completely on awakening and then discard that urine specimen. Record the time the voided
specimen is discarded and the time the test is begun.
2. Save all urine voided during the next 24 hours, including the first specimen voided the next morning.
3. Add the urine voided the next morning (as close to the ending time as possible) to the collection container. The
24-hour test is then terminated, and the ending time is recorded.
4. Use a urinal, wide-mouth container, special toilet device, bedpan, or the collection container itself to catch urine. It
is probably easier for women to void into another wide-mouth receptacle first and then to transfer the entire
specimen carefully to the collection bottle. Men may find it simpler to void directly into the 24-hour collection
container.
5. It is most important that all urine be saved in the 24-hour container. Ideally, the container should be refrigerated or
placed on ice.
6. Test results are calculated on the basis of a 24-hour output. Unless all urine is saved, results will not be accurate.
Moreover, these tests are usually expensive, complicated, and necessary for the evaluation and treatment of the
patient's condition.
7. If the laboratory requests an aliquot, record total amount, mix well, and aliquot the requested amount.
8. Always check with your laboratory as to the preservative needed—different laboratories may have different
requirements.

Posttest Patient Aftercare
1. Interpret test outcome and monitor appropriately.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .

ROUTINE URINALYSIS (UA) AND RELATED TESTS
The process of UA determines the following properties of urine: color, odor, turbidity, specific gravity, pH, glucose,
ketones, blood, protein, bilirubin, urobilinogen, nitrite, leukocyte esterase, and other abnormal constituents revealed by
microscopic examination of the urine sediment. A 10-mL urine specimen is usually sufficient for conducting these tests (
Table 3.4).

Table 3.4 Normal Values in Urinalysis
General Characteristics and
Measurements

Chemical
Determinations

Microscopic Examination of Sediment

Color: pale yellow to amber
Appearance: clear to slightly hazy
Specific gravity: 1.005–1.025 with a normal
fluid intake
pH: 4.5–8.0; average person has a pH of
about 5 to 6
Volume: 600–2,500 mL/24 h; average 1200
mL/24 h

Glucose: negative
Ketones: negative
Blood: negative

Casts negative: occasional hyaline casts
Red blood cells: negative or rare
Crystals: negative (none)

Protein: negative

White blood cells: negative or rare

Bilirubin: negative
Urobilinogen: 0.5–4.0
mg/d
Nitrate for bacteria:
negative
Leukocyte esterase:
negative

Epithelial cells: few; hyaline casts 0–1/lpf
(low-power field)

Urine Volume
Urine volume measurements are part of the assessment for fluid balance and kidney function. The normal volume of
urine voided by the average adult in a 24-hour period ranges from 600 to 2500 mL; the typical amount is about 1200 mL.
The amount voided over any period is directly related to the individual's fluid intake, the temperature and climate, and the
amount of perspiration that occurs. Children void smaller quantities than adults, but the total volume voided is greater in
proportion to their body size.
The volume of urine produced at night is <700 mL, making the day-to-night ratio approximately 2:1 to 4:1.
Urine volume depends on the amount of water excreted by the kidneys. Water is a major body constituent; therefore, the
amount excreted is usually determined by the body's state of hydration. Factors that influence urine volume include fluid
intake, fluid loss from nonrenal sources, variations in the secretion of antidiuretic hormone (ADH), and the necessity to
excrete increased amount of solutes such as glucose or salts. Polyuria is marked increase of urine production. Oliguria is
decreased urinary output. The extreme form of this process is anuria, a total lack of urine production.
Reference Values
Normal
600–2500 mL in 24 hours or 600–2500 mL/day
Procedure
1. Collect a 24-hour urine specimen and keep it refrigerated or on ice.
2. Record the exact collection starting time and collection ending time on the specimen container and in the patient's
health care record.
3. Transfer the specimen container to the laboratory refrigerator when the collection is completed. Complete the
proper forms and document accordingly.
4. Ascertain volume by measuring the entire urine amount in a graduated and appropriately calibrated pitcher or other
receptacle. The total volume is recorded as urine volume in milliliters (cubic centimeters) per 24 hours.
Clinical Implications
1. Polyuria (increased urine output) with elevated blood urea nitrogen (BUN) and creatinine levels
a. Diabetic ketoacidosis
b. Partial obstruction of urinary tract
c. Some types of tubular necrosis (aminoglycoside)
2. Polyuria with normal BUN and creatinine
a. Diabetes mellitus and diabetes insipidus
b. Neurotic states (compulsive water drinking)
c. Certain tumors of brain and spinal cord
3. Oliguria (<200 mL in adults, or <15–20 mL/kg in children, per 24 hours)

a. Renal causes
1. Renal ischemia
2. Renal disease due to toxic agents (certain drugs are toxic to the renal system)
3. Glomerulonephritis
b. Dehydration caused by prolonged vomiting, diarrhea, excessive diaphoresis, or burns
c. Obstruction (mechanical) of some area of the urinary tract or system
d. Cardiac insufficiency
4. Anuria (<100 mL in 24 hours)
a. Complete urinary tract obstruction
b. Acute cortical necrosis (cortex of the kidney)
c. Glomerulonephritis (acute, necrotizing)
d. Acute tubular necrosis
e. Hemolytic transfusion reaction
Interfering Factors
1. Polyuria
a. Intravenous glucose or saline
b. Pharmacologic agents such as thiazides and other diuretics
c. Coffee, alcohol, tea, caffeine
2. Oliguria
a. Water deprivation, dehydration
b. Excessive salt intake
Interventions
Pretest Patient Preparation
1. Explain the purpose and procedure of the test.
2. Withhold diuretics for 3 days before the test. Check with clinician.
3. Avoid excessive water (liquid) intake and excessive salt intake. Advise patients to avoid salty foods and added salt
in the diet. Eliminate caffeine and alcohol. Determine the patient's usual liquid intake and request that intake not be
increased beyond this daily amount during testing.
4. Follow guidelines in Chapter 1 for safe, effective, pretest care.
Posttest Patient Aftercare
1. Patient can resume normal fluid and dietary intake and medications, unless specifically ordered otherwise.
2. Interpret test outcomes and counsel appropriately.
3. Follow guidelines in Chapter 1 for safe, effective, posttest care.
Urine Specific Gravity (SG)
Specific gravity (SG) is a measurement of the kidneys' ability to concentrate urine. The test compares the density of urine
against the density of distilled water, which has an SG of 1.000. Because urine is a solution of minerals, salts, and
compounds dissolved in water, the SG is a measure of the density of the dissolved chemicals in the specimen. As a
measurement of specimen density, SG is influenced by both the number of particles present and the size of the particles.
Osmolality is a more exact measurement and may be needed in certain circumstances.
The range of urine SG depends on the state of hydration and varies with urine volume and the load of solids to be
excreted under standardized conditions; when fluid intake is restricted or increased, SG measures the concentrating and
diluting functions of the kidney. Loss of these functions is an indication of renal dysfunction.
Reference Values
Normal
Normal hydration and volume: 1.005–1.030 (usually between 1.010 and 1.025)
Concentrated urine: 1.025–1.030+
Dilute urine: 1.001–1.010
Infant < 2 years old: 1.001–1.018
Procedure
1. Test SG with the use of a multiple-test dipstick that has a separate reagent area for SG. An indicator changes color
in relation to ionic concentration, and this result is translated into a value for SG.
2. Determine SG with a refractometer or total solids meter. The refractive index is the ratio of the velocity of light in air
to the velocity of light in the test solution. A drop of urine is placed on a clear glass plate of the urinometer and
another plate is pressed on top of the urine sample. The path of light is deviated when it enters the solution, and
the degree of deviation (refraction) is directly proportional to the density of the solution.
3. The urinometer (hydrometer) is the least accurate method. It consists of a bulb-shaped instrument that contains a
scale calibrated in SG readings. Urine (10–20 mL) is transferred into a small test tube–like cylinder, and the
urinometer is floated in the urine. The SG is read off the urinometer at the meniscus level of the urine. This method
is becoming obsolete owing to the ease of dipstick testing.
4. Specimen collection
a. For regular UA testing, about 20 mL of a random sample is needed for testing (UA including SG).
b. When a special evaluation of SG is ordered separately from the UA, the patient should fast for 12 hours before
specimen collection.

Clinical Implications
1. Normal SG: SG values usually vary inversely with the amount of urine excreted (decreased urine volume =
increased SG). However, this relationship is not valid in certain conditions, including:
a. Diabetes—increased urine volume, increased SG
b. Hypertension—normal volume, decreased SG
c. Early chronic renal disease—increased volume, decreased SG
2. Hyposthenuria (low SG, 1.001–1.010) occurs in the following conditions:
a. Diabetes insipidus (low SG with large urine volume). It is caused by absence or decrease of ADH, a hormone
that triggers kidney absorption of water. Without ADH, the kidneys produce excessive amounts of urine that are
not reabsorbed (sometimes 15–20 L/day).
b. Glomerulonephritis (kidney inflammation without infection) and phelonephritis (kidney inflammation with
bacterial infection, but not in the acute type of this disease). SG can be low in glomerulonephritis, with
decreased urine volume. Tubular damage affects the kidneys' ability to concentrate urine.
c. Severe renal damage with disturbance of both concentrating and diluting abilities of urine. The SG is low (1.010)
and fixed (varying little from specimen to specimen); this is termed isosthenuria.
3. Hypersthenuria (increased SG, 1.025–1.035) occurs in the following conditions:
a. Diabetes mellitus
b. Nephrosis
c. Excessive water loss (dehydration, fever, vomiting, diarrhea)
d. Increased secretion of ADH and diuretic effects related to the stress of a surgical procedure
e. Congestive heart failure
f. Toxemia of pregnancy
Interfering Factors
1. Radiopaque x-ray contrast media, minerals, and dextran may cause falsely high SG readings on the refractometer.
The reagent dipstick method is not affected by high-molecular-weight substances.
2. Temperature of urine specimens affects SG; cold specimens produce falsely high values using the hydrometer.
3. Highly buffered alkaline urine may also cause low readings (with dipsticks only).
4. Elevated readings may occur in the presence of moderate amounts of protein (100–750 mg/dl) or with patients
receiving intravenous albumin.
5. Detergent residue (on specimen containers) can produce elevated SG results.
6. Diuretics and antibiotics cause high readings.
7. See Appendix J for drugs that affect test outcomes.
Intervention
Pretest Patient Preparation
1. Explain the purpose and procedure for urine collection.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes, counsel, and monitor appropriately for conditions associated with altered SG.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Urine Osmolality
Osmolality, a more exact measurement of urine concentration than SG, depends on the number of particles of solute in a
unit of solution. More information concerning renal function can be obtained if serum and urine osmolality tests are run at
the same time. The normal ratio between urine and serum osmolality is 3:1. A high urine-to-serum ratio is seen with
concentrated urine. With poor concentrating ability, the ratio is low.
Whenever a precise measurement is indicated to evaluate the concentrating and diluting ability of the kidney, this test is
done. Urine osmolality during water restriction is an accurate test of decreased kidney function. It is also used to monitor
the course of renal disease; to monitor fluid and electrolyte therapy; to establish the differential diagnosis of
hypernatremia, hyponatremia, and polyuria; and to evaluate the renal response to ADH.
Reference Values
Normal
24-hour specimen: 300–900 mOsm/kg of H 2O
Random specimen: 50–1200 mOsm/kg of H 2O
Urine-to-serum ratio: 1:1 to 3:1
Procedure
1. Tell patient that this is a 24-hour urine collection test.
2. For the 24-hour test, the patient voids at approximately 7:00 a.m. (0700). All of the urine voided is saved in a
special 24-hour collection container kept on ice or refrigerated. A high-protein diet may be ordered.
3. At the end of the test, the specimen is labeled and sent to the laboratory.
4. Simultaneous determination of serum osmolality may be done. A high urine-to-serum ratio is seen with
concentrated urine.
Clinical Implications

1. Osmolality is increased in:
a. Prerenal azotemia
b. Congestive heart failure
c. Addison's disease
d. Syndrome of inappropriate ADH secretion (SIADH)
e. Dehydration
f. Amyloidosis
g. Hyponatremia
2. Osmolality is decreased in:
a. Acute renal failure
b. Diabetes insipidus
c. Hypokalemia
d. Hypernatremia
e. Primary polydipsia
f. Hypercalcemia
g. Compulsive water drinking (increased fluid intake)
3. Urine-to-serum ratio is:
a. Increased in prerenal azotemia
b. Decreased in acute tubular necrosis
Interfering Factors
1. Intravenous sodium administration
2. Intravenous dextrose and water administration
Interventions
Pretest Patient Preparation
1. Explain purpose and procedure of the test to the patient.
2. A normal diet is prescribed for 3 days before testing.
3. To increase sensitivity of the osmolality test, a high-protein diet may be ordered for 3 days before the test. No
liquids with the evening meal and no food or liquids should be taken after the evening meal until collection. Check
with your laboratory if the patient has diabetes.
4. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Provide the patient with foods and fluids as soon as the last urine sample is obtained.
2. Interpret test outcomes and monitor appropriately.
3. Follow guidelines in Chapter 1 for safe, effective, posttest care.
Urine Appearance
The first observation made about a urine specimen is usually its appearance, which generally refers to the clarity of the
specimen.
Cloudy urine signals a possible abnormal constituent, such as white blood cells (WBCs), RBCs, or bacteria. On the other
hand, excretion of cloudy urine may not be abnormal because a change in urine pH can cause precipitation, within the
bladder, of normal urinary components. Alkaline urine may appear cloudy because of phosphates; acid urine may appear
cloudy because of urates.
Reference Values
Normal
Fresh urine is clear to slightly hazy.
Procedure
1. Observe the clarity of a fresh urine sample by visually examining a well-mixed specimen in front of a light source.
2. Use common terms to report appearance, including the following: clear, hazy, slightly cloudy, cloudy, turbid, and
milky.
3. Document results. The degree of turbidity should correspond to the amount of material observed under the
microscope.
Clinical Implications
1. Pathologic urines are often turbid or cloudy; however, normal urine can also appear cloudy.
2. Urine turbidity may result from urinary tract infections (UTIs).
3. Urine may be cloudy because of the presence of RBCs, WBCs, epithelial cells, or bacteria.
Interfering Factors
1. After ingestion of food, urates, carbonates, or phosphates may produce cloudiness in normal urine on standing.
2. Semen or vaginal discharges mixed with urine are common causes of turbidity.
3. Fecal contamination causes turbidity.

4. Extraneous contamination (eg, talcum, vaginal creams, radiographic contrast media) can cause turbidity.
5. “Greasy” cloudiness may be caused by large amounts of fat.
6. Often, normal urine develops a haze or turbidity after refrigeration or standing at room temperature because of
precipitation of crystals of calcium oxalate or uric acid.
Urine Color
The yellow color of urine is caused by the presence of the pigment urochrome, a product of metabolism that under
normal conditions is produced at a constant rate. The actual amount of urochrome produced depends on the body's
metabolic state, with increased amounts being produced in thyroid conditions and fasting states.
Urine specimens may vary in color from pale yellow to dark amber. Variations in the yellow color are related to the body's
state of hydration. The darker amber color may be directly related to the urine concentration or SG.
Reference Values
Normal
The normal color of urine is pale yellow to amber.
Straw-colored urine is normal and indicates a low SG, usually < 1.010. (The exception may be a patient with an elevated
blood glucose concentration, whose urine is very pale yellow but has a high SG.)
Amber-colored urine is normal and indicates a high SG and a small output of urine.
Procedure
Observe and record the color of freshly voided urine.
Clinical Implications
1. Almost colorless (straw-colored) urine:
a. Large fluid intake
b. Chronic interstitial nephritis
c. Untreated diabetes mellitus
d. Diabetes insipidus
e. Alcohol and caffeine ingestion
f. Diuretic therapy
g. Nervousness
2. Orange-colored (amber) urine:
a. Concentrated urine caused by fever, sweating reduced fluid intake, or first morning specimen
b. Bilirubin (yellow foam when shaken)
c. Carrots or vitamin A ingestion (large amounts)
d. Certain urinary tract medications (eg, phenazopyridine [Pyridium], nitrofurantoin)
3. Brownish-yellow or greenish-yellow urine may indicate bilirubin in the urine that has been oxidized to biliverdin
(greenish foam when shaken).
4. Green urine:
a. Pseudomonal infection
b. Indican
c. Chlorophyll
5. Pink to red urine:
a. RBCs
b. Hemoglobin, methemoglobin, oxyhemoglobin
c. Myoglobin
d. Porphyrins
6. Brown-black urine:
a. RBCs oxidized to methemoglobin
b. Methemoglobin
c. Homogentisic acid (alkaptonuria)
d. Melanin or melanogen
e. Phenol poisoning (Lysol)
7. Smoky urine may be caused by RBCs.
8. Milky urine is associated with fat, cystinuria, many WBCs, or phosphates (not pathologic).
Interfering Factors
1. Normal urine color darkens on standing because of the oxidation of urobilinogen to urobilin. This decomposition
process starts about 30 minutes after voiding.
2. Some foods cause changes in urine color:
a. Beets turn the urine red.
b. Rhubarb can cause brown urine.
3. Many drugs alter the color of urine:
a. Cascara and senna laxatives in the presence of acid urine turn the urine reddish brown; in the presence of
alkaline urine, they turn the urine red.
b. Bright-yellow color in alkaline urine may be a result of riboflavin or phenazopyridine.
c. Urine that darkens on standing may indicate antiparkinsonian agents such as levodopa (Sinemet).
d. Black urine may be caused by cascara, chloroquine, iron salts (ferrous sulfate, ferrous fumarate, ferrous
gluconate), metronidazole, nitrofurantoin, quinine, or senna.
e. Blue urine may be caused by triamterene.
f. Blue-green urine may be caused by amitriptyline, methylene blue, or mitoxantrone.
g. Orange urine may be caused by heparin, phenazopyridine, rifampin, sulfasalazine, or warfarin.
h. Red-pink urine may be caused by chloroxazone, daunorubicin, doxorubicin, heparin, ibuprofen, methyldopa,
phenytoin, rifampin, or senna.

i. Pink to brown urine may be caused by laxatives.
j. Brown urine may be caused by chloroquine, furazolidone, or primaquine.
k. Green urine may be caused by indomethacin.
Interventions
Pretest Patient Preparation
Assess color of urine; instruct patient to monitor and to report abnormal urine colors.

Clinical Alert
1. If the urine is a red color, do not assume drug causation. Check the urine for hemoglobin. Question the patient
regarding hematuria and recent activity, injury, or infection. Sometimes, vigorous exercise can bring on
hematuria.
2. Red urine that is negative for occult blood is an indication that porphyria may be present. Report at once and
document test results.
3. Other grossly abnormal colors (eg, black, brown) should be documented and reported.
Posttest Patient Aftercare
1. Interpret abnormal urine colors and counsel appropriately.
2. Explain that follow-up testing may be needed.
Urine Odor
Normal, freshly voided urine has a faint odor owing to the presence of volatile acids. It is not generally offensive.
Although not part of the routine UA, abnormal odors should be noted.
Reference Values
Normal
Fresh urine from most healthy persons has a characteristic aromatic odor.
Procedure
Smell the urine and record perceptions.
Clinical Implications
1. The urine of patients with diabetes mellitus may have a fruity (acetone) odor because of ketosis.
2. UTIs result in foul-smelling urine because of the presence of bacteria, which split urea to form ammonia.
3. The urine of infants with an inherited disorder of amino acid metabolism known as “maple syrup urine disease”
smells like maple or burnt sugar.
4. Cystinuria and homocystinuria result in a sulfurous odor.
5. Oasthouse urine (Smith-Strang) disease causes an odor associated with the smell of a brewery (yeasts, hops).
6. In phenylketonuria, a musty, mousy smell may be evident.
7. Tyrosinemia is characterized by a cabbage-like or “fishy” urine odor.
8. Butyric/hexanoic acidemia produces a urine odor resembling that of sweaty feet.
Interfering Factors
1. Some foods, such as asparagus, produce characteristic urine odors.
2. Bacterial activity produces ammonia from the decomposition of urea, with its characteristic pungent odor.
Urine pH
The symbol pH expresses the urine as a dilute acid or base solution and measures the free hydrogen ion (H +)
concentration in the urine; 7.0 is the point of neutrality on the pH scale. The lower the pH, the greater the acidity; the
higher the pH, the greater the alkalinity. The pH is an indicator of the renal tubules' ability to maintain normal hydrogen
ion concentration in the plasma and extracellular fluid. The kidneys maintain normal acid-base balance primarily through
reabsorption of sodium and tubular secretion of hydrogen and ammonium ions. Secretion of an acid or alkaline urine by
the kidneys is one of the most important mechanisms the body has for maintaining a constant body pH.
Urine becomes increasingly acidic as the amount of sodium and excess acid retained by the body increases. Alkaline
urine, usually containing bicarbonate-carbonic acid buffer, is normally excreted when there is an excess of base or alkali
in the body.
The importance of urinary pH lies primarily in determining the existence of systemic acid-base disorders of metabolic or
respiratory origin and in the management of urinary conditions that require the urine to be maintained at a specific pH.
Control of Urine pH
Control of urinary pH is important in the management of several diseases, including bacteriuria, renal calculi, and drug
therapy in which streptomycin or methenamine mandelate is being administered.
1. Renal calculi
a. Renal stone formation partially depends on the pH of urine. Patients being treated for renal calculi are frequently
given diets or medication to change the pH of the urine so that kidney stones will not form.
b. Calcium phosphate, calcium carbonate, and magnesium phosphate stones develop in alkaline urine. In such
instances, the urine must be kept acidic (see Diet, number 4, below).
c. Uric acid, cystine, and calcium oxalate stones precipitate in acid urines. Therefore, as part of treatment, the

urine should be kept alkaline (see Diet, number 4, below).
2. Drug treatment
a. Streptomycin, neomycin, and kanamycin are effective for treating genitourinary tract infections, provided the
urine is alkaline.
b. During sulfa therapy, alkaline urine should help prevent formation of sulfonamide crystals.
c. Urine should also be kept persistently alkaline in the presence of salicylate intoxication (to enhance excretion)
and during blood transfusions.
3. Clinical conditions
a. The urine should be kept acidic during treatment of UTI or persistent bacteriuria and during management of
urinary calculi that develop in alkaline urine.
b. An accurate measurement of urinary pH can be made only on a freshly voided specimen. If the urine must be
kept for any length of time before analysis, it must be refrigerated.
c. Highly concentrated urine, such as that formed in hot, dry environments, is strongly acidic and may produce
irritation.
d. During sleep, decreased pulmonary ventilation causes respiratory acidosis; as a result, urine becomes more
acidic.
e. Chlorothiazide diuretic administration causes acid urine to be excreted.
f. Bacteria from a UTI or from bacterial contamination of the specimen produce alkaline urine. Urea is converted to
ammonia.
4. Diet
a. A vegetarian diet that emphasizes citrus fruits and most vegetables, particularly legumes, helps keep the urine
alkaline. Alkaline urine after meals is a normal response to the secretions of hydrochloric acid in gastric juice
(“alkaline tide”).
b. A diet high in meat and protein keeps the urine acidic.
c. Cranberry juice is the only fruit that will maintain an acidic urine, and it has long been used as a remedy for
minor UTIs.
Reference Values
Normal
The pH of normal urine can vary widely, from 4.6 to 8.0.
The average pH value is about 6.0 (acidic).
Procedure
1. Use reagent strips for a dipstick measurement. They produce a spectrum of color changes from orange to
green-blue to identify pH ranges from 5.0 to 9.0.
2. Dip the reagent strip into a freshly voided urine specimen, and compare the color change with the standardized
color chart on the bottle that correlates color results with pH values.
3. Maintenance of the urine at a consistent pH requires frequent urine pH testing.
Clinical Implications To be useful, the urine pH measurement must be used in conjunction with other diagnostic
information. For example, in renal tubular necrosis, the kidney is not able to excrete a urine that is strongly acidic.
Therefore, if the urine pH is 5.0, renal tubular necrosis is eliminated as a possible diagnosis.
1. Acidic urine (pH < 7.0) occurs in:
a. Metabolic acidosis, diabetic ketosis, diarrhea, starvation, uremia
b. UTIs caused by Escherichia coli
c. Respiratory acidosis (carbon dioxide retention)
d. Renal tuberculosis
e. Pyrexia
2. Alkaline urine (pH > 7.0) occurs in:
a. UTIs caused by urea-splitting bacteria ( Proteus and Pseudomonas)
b. Renal tubular acidosis, chronic renal failure
c. Metabolic acidosis (vomiting)
d. Respiratory alkalosis involving hyperventilation (“blowing off” carbon dioxide)
e. Potassium depletion
Interfering Factors
1. With prolonged standing, the pH of a urine specimen becomes alkaline because bacteria split urea and produce
ammonia.
2. Ammonium chloride and mandelic acid may produce acid urines.
3. Runover between the pH testing area and the highly acidic protein area on the dipsticks may cause alkaline urine to
give an acidic reading.
4. Sodium bicarbonate, potassium citrate, and acetazolamide may produce alkaline urine.
5. Urine becomes alkaline after eating because of excretion of stomach acid; this is known as the “alkaline tide.”

Clinical Alert
The pH of urine never reaches 9, either in normal or abnormal conditions. Therefore, a pH finding of 9 indicates that a
fresh specimen should be obtained to ensure the validity of the UA.
Interventions
Pretest Patient Preparation
1. Explain test purpose and specimen collection procedure.

2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor patient appropriately (see Control of Urine pH ).
2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Urine Blood or Hemoglobin (Hb)
The presence of free hemoglobin in the urine is referred to as hemoglobinuria. Hemoglobinuria can be related to
conditions outside the urinary tract and occurs when there is such extensive or rapid destruction (intravascular
hemolysis) of circulating erythrocytes that the reticuloendothelial system cannot metabolize or store the excess free
hemoglobin. The hemoglobin is then filtered through the glomerulus. Hemoglobinuria may also occur as a result of lysis
of RBCs in the urinary tract.
When intact RBCs are present in the urine, the term hematuria is used. Hematuria is most closely related to disorders of
the renal or genitourinary systems in which bleeding is the result of trauma or damage to these organs or systems.
This test detects RBCs, hemoglobin, and myoglobin in urine. Blood in urine is always an indicator of damage to the
kidney or urinary tract.
The use of both a urine dipstick measurement and microscopic examination of urine provides a complete clinical
evaluation of hemoglobinuria and hematuria. Newer forms of dipsticks contain a lysing reagent that reacts with occult
blood and detects intact as well as lysed RBCs.
When urine sediment is positive for occult blood but no RBCs are seen microscopically, myoglobinuria can be suspected.
Myoglobinuria is caused by excretion of myoglobin, a muscle protein, into the urine as a result of (1) traumatic muscle
injury, such as may occur in automobile accidents, football injuries, or electric shock; (2) a muscle disorder, such as an
arterial occlusion to a muscle or muscular dystrophy; (3) certain kinds of poisoning, such as carbon monoxide or fish
poisoning; or (4) malignant hyperthermia related to administration of certain anesthetic agents. Myoglobin can be
distinguished from free hemoglobin in the urine by chemical tests.
Reference Values
Normal
Negative/none
Procedure
1. Collect a fresh, random urine specimen.
a. Hemoglobinuria (hemoglobin in urine)
1. Dip reagent sticks into the urine; the color change on the dipstick correlates with a standardized color chart
specifically used with that particular type of dipstick.
2. The color chart indicates color gradients for negative, moderate, and large amounts of hemoglobin.
b. Hematuria (RBCs in urine)
1. This dipstick method allows detection of intact RBCs when the number is greater than 10 cells/µL of urine.
The color change appears stippled on the dipstick.
2. The degree of hematuria can be estimated by the intensity of the speckled pattern.
2. Centrifuge the urine sample and examine the sediment microscopically (see Microscopic Examination of Urine
Sediment) to verify the presence of RBCs.
a. Hemoglobinuria is suspected when no RBCs are seen or the number seen does not correspond to the degree of
color on the dipstick.
b. Myoglobinemia may be suspected if the urine is cherry-red, no RBCs are seen, and blood serum enzymes for
muscle destruction are elevated.
Clinical Implications
1. Hematuria is found in:
a. Acute UTI (cystitis)
b. Lupus nephritis
c. Urinary tract or renal tumors
d. Urinary calculi (intermittent hematuria)
e. Malignant hypertension
f. Glomerulonephritis (acute or chronic)
g. Pyelonephritis
h. Trauma to kidneys
i. Polycystic kidney disease
j. Leukemia
k. Thrombocytopenia
l. Strenuous exercise
m. Benign familial or recurrent hematuria (asymptomatic hematuria without proteinuria; other clinical and laboratory
data are normal)
n. Heavy smokers
2. Hemoglobinuria is found in:
a. Extensive burns
b. Transfusion reactions (incompatible blood products)
c. Febrile intoxication

d. Certain chemical agents and alkaloids (poisonous mushrooms, snake venom)
e. Malaria
f. Bleeding resulting from operative procedures on the prostate (can be difficult to control, especially in the
presence of malignancies)
g. Hemolytic disorders such as sickle cell anemia, thalassemia, and glucose-6-phosphate dehydrogenase
deficiency
h. Paroxysmal hemoglobinuria (large quantities of hemoglobin appear in urine at irregular intervals)
i. Kidney infarction
j. Hemolysis occurring while the urine is in the urinary tract (RBC lysis from hypotonic urine or alkaline urine)
k. Fava bean sensitivity (causes severe hemolytic anemia)
l. Disseminated intravascular coagulation (DIC)
m. Strenuous exercise (“march hemoglobinuria”)

Clinical Alert
One of the early indicators of possible renal or urinary tract disease is the appearance of blood in the urine. This does
not mean that blood will be present in every voided specimen, but in most cases of renal or urinary tract disease, occult
blood will appear in the urine with a reasonable degree of frequency. Any positive test for blood should be rechecked
on a new urine specimen. If blood still appears, the patient should be further evaluated.
Interfering Factors
1. Drugs causing a positive result for blood or hemoglobin include:
a. Drugs toxic to the kidneys (eg, bacitracin, amphotericin)
b. Drugs that alter blood clotting (warfarin [Coumadin])
c. Drugs that cause hemolysis of RBCs (aspirin)
d. Drugs that may give a false-positive result (eg, bromides, copper, iodides, oxidizing agents)
2. High doses of ascorbic acid or vitamin C may cause a false-negative result.
3. High SG or elevated protein reduces sensitivity.
4. Myoglobin produces a false-positive result.
5. Hypochlorites or bleach used to clean urine containers causes false-positive results.
6. Menstrual blood may contaminate the specimen and alter results.
7. Prostatic infections may cause false-positive results.
8. See Appendix J for a complete list of drugs that affect test outcomes.
Interventions
Pretest Patient Preparation
1. Explain test purpose and procedure for urine specimen collection.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and explain possible need for follow-up testing.
2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Urine Protein (Albumin), Qualitative and 24-Hour
The presence of increased amounts of protein in the urine can be an important indicator of renal disease. It may be the
first sign of a serious problem and may appear before any other clinical symptoms. However, there are other physiologic
conditions (eg, exercise, fever) that can lead to increased protein excretion in urine. Also, there are some renal disorders
in which proteinuria is absent.
In a healthy renal and urinary tract system, the urine contains no protein or only trace amounts. These consist of albumin
(one third of normal urine protein is albumin) and globulins from the plasma. Because albumin is filtered more readily
than the globulins, it is usually abundant in pathologic conditions. Therefore, the term albuminuria is often used
synonymously with proteinuria.
Normally, the glomeruli prevent passage of protein from the blood to the glomerular filtrate. Therefore, the presence of
protein in the urine is the single most important indication of renal disease. If more than a trace of protein is found
persistently in the urine, a quantitative 24-hour evaluation of protein excretion is necessary.
Reference Values for 24-Hour Urine
Normal
Adult male: 10–140 mg/L or 1–14 mg/dL
Adult female: 30–100 mg/L or 3–10 mg/dL
Child: <10 years old: 10–100 mg/L or 1–10 mg/dL
Reference Values—Qualitative
Normal
Negative
Procedure
Qualitative Protein Collection
1. Collect a random urine sample in a clean container and test it as soon as possible.
2. Use a protein reagent dipstick and compare the test result color with the color comparison chart provided on the

reagent strip bottle. Protein can also be detected by turbidimetric methods using sulfosalicylic acid.
3. Test a new second specimen and investigate any interfering factors if one of these methods produces positive
results. A 24-hour urine test may then be ordered for a quantitative measurement of protein.
24-Hour Urine Protein Collection
1.
2.
3.
4.

Label a 24-hour urine container with the name of the patient, the test, and the date and time the test is started.
Refrigerate the specimen as it is being collected.
See general instructions for 24-hour urine collection listed (see Long-Term, Timed Urine Specimen, page 171).
Record the exact starting and ending times for the 24-hour collection on the specimen container and on the
patient's record. (The usual starting and ending times are 0700 to 0700.)

Clinical Implications
1. Proteinuria occurs by two main mechanisms: damage to the glomeruli or a defect in the reabsorption process that
occurs in the tubules.
a. Glomerular damage
1. Glomerulonephritis, acute and chronic
2. Systemic lupus erythematosus (SLE)
3. Malignant hypertension
4. Amyloidosis
5. Diabetes mellitus
6. Nephrotic syndrome
7. Polycystic kidney disease
b. Diminished tubular reabsorption
1. Renal tubular disease
2. Pyelonephritis, acute and chronic
3. Cystinosis
4. Wilson's disease
5. Fanconi's syndrome (defect of proximal tubular function)
6. Interstitial nephritis
2. In pathologic states, the level of proteinuria is rarely constant, so not every sample of urine is abnormal in patients
with renal disease, and the concentration of protein in the urine is not necessarily indicative of the severity of renal
disease.
3. Proteinuria may result from glomerular blood flow changes without the presence of a structural abnormality, as in
congestive heart failure.
4. Proteinuria may be caused by increased serum protein levels.
a. Multiple myeloma (Bence Jones protein)
b. Waldenström's macroglobulinemia
c. Malignant lymphoma
5. Proteinuria can occur in other nonrenal disease (“functional proteinuria”)
a. Acute infection, septicemia
b. Trauma, stress
c. Leukemia, hematologic disorders
d. Toxemia, preeclampsia of pregnancy
e. Hyperthyroidism
f. Vascular disease (hypertension), cardiac disease
g. Renal transport rejection
h. Central nervous system lesions
i. Poisoning from turpentine, phosphorus, mercury, gold, lead, phenol, opiates, or other drugs
j. Hereditary, sickle cell, oxalosis
6. Large numbers of leukocytes accompanying proteinuria usually indicate infection at some level in the urinary tract.
Large numbers of both leukocytes and erythrocytes indicate a noninfectious inflammatory disease of the
glomerulus. Proteinuria associated with pyelonephritis may have as many RBCs as WBCs.
7. Proteinuria does not always accompany renal disease.
a. Pyelonephritis
b. Urinary tract obstructions
c. Nephrolithiasis
d. Tumors
e. Congenital malformations
f. Renal artery stenosis
8. Proteinuria is often associated with the finding of casts on sediment examination because protein is necessary for
cast formation.
9. Postural proteinuria results from the excretion of protein by some patients when they stand or move about. This
type of proteinuria is intermittent and disappears when the patient lies down. Postural proteinuria occurs in 3% to
15% of healthy young adults. It is also known as orthostatic proteinuria.
Collecting the Specimen for Orthostatic Proteinuria
1. The patient is instructed to void at bedtime and to discard this urine.
2. The next morning, a urine specimen is collected immediately after the patient awakens and before the patient has
been in an upright position for longer than 1 minute. This may involve the use of a bedpan or urinal.
3. A second specimen is collected after the patient has been standing or walking for at least 2 hours.
4. With postural proteinuria, the first specimen contains no protein, but the second one is positive for protein.
5. The urine looks microscopically normal; no RBCs or WBCs are apparent. Orthostatic proteinuria is considered a

benign condition and slowly disappears with time. Progressive renal impairment usually does not occur.

Clinical Alert
1. Proteinuria of > 2000 mg/24 hours in an adult or = 40 mg/24 hours in a child usually indicates a glomerular
cause.
2. Proteinuria of > 3500 mg/24 hours points to a nephrotic syndrome.
Interfering Factors for Qualitative Protein Test
1. Because of renal vasoconstriction, the presence of a functional, mild, and transitory proteinuria is associated with:
a. Strenuous exercise up to 300 mg/24 hours
b. Severe emotional stress, seizures
c. Cold baths, exposure to very cold temperatures
2. Increased protein in urine occurs in these benign states:
a. Fever and dehydration (salt depletion)
b. Non–immunoglobulin E food allergies
c. Salicylate therapy
d. In the premenstrual period and immediately after delivery
3. False or accidental proteinuria may occur because of a mixture of pus and RBCs in the urinary tract related to
infections, menstrual or vaginal discharge, mucus, or semen.
4. False-positive results can occur from incorrect use and interpretation of the color reagent strip test.
5. Alkaline, highly buffered urine can produce false-positive results on the dipstick test.
6. Very dilute urine may give a falsely low protein value.
7. Certain drugs may cause false-positive or false-negative urine protein tests (see Appendix J).
8. Radiographic contrast agents may produce false-positive results with turbidimetric measurements.
Interventions
Pretest Patient Preparation
1. Instruct the patient about the purpose and procedure for collection of the 24-hour urine specimen. Emphasize the
importance of compliance with the procedure.
2. Food and fluids are permitted; however, fluids should not be forced because very dilute urine can produce
false-negative values.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and explain the possible need for follow-up testing (eg, urine differential/electrophoresis)
and treatment (to prevent progression to renal failure).
2. See guidelines in Chapter 1 for safe, effective, informed posttest care .
3. See Chapter 8 for protein electrophoresis.
Microalbuminuria/Albumin (24-Hour Urine)
Microalbuminuria is an increase in urinary albumin that is below the detectable range of the standard protein dipstick test.
It is not a different chemical form of albumin. Microalbuminuria occurs long before clinical proteinuria becomes evident.
This test allows for the routine detection of low concentrations of albumin in the urine. This test has become a standard
for the screening, monitoring, and detection of deteriorating renal function in diabetic patients. Studies have shown that
diabetic patients who progress to renal failure first excrete micro amounts of albumin and that, at this stage, intervening
treatment can reverse the proteinuria and thus prevent progression to renal failure. This test is also used to monitor
compliance of blood pressure control, glucose control, and protein restriction.
Reference Values
Normal
<30 mg/24 hours (<30 mg/day) or < 20 mg/L (10-hour collection)
Procedure
1. 24-hour: Same as for total urine protein
2. 10-hour: Overnight collection
a. Last voiding before sleep (10:00 p.m.)
b. Collect all urine at first morning voiding (8:00 a.m.)
These results approximate 24-hour collection.
Clinical Implications
Increased microalbuminuria is associated with:
1.
2.
3.
4.

Diabetes with early diabetic nephropathy
Hypertension—heart disease
Generalized vascular disease
Preeclampsia

Interfering Factors

1. Strenuous exercise
2. Hematuria (menses)
3. High-protein diet or high salt levels
Interventions
Pretest Patient Preparation The pretest care is the same as for 24-hour protein.
Posttest Patient Aftercare
1. Albumin excretion > 30 mg/24 hours or > 20 mg/L/10 hours indicates an abnormal excretion.
a. Patient management should be reviewed.
b. Patient compliance can be checked by glycosylated hemoglobin to determine further control.
2. Patients with borderline results should be assessed on more than one occasion before the significance of a given
urine measurement is finally judged.
3. The posttest care is the same as for 24-hour total protein.
Urine ß 2-Microglobulin
ß 2-Microglobulin, an amino acid peptide component of the lymphatic human lymphocyte antibody (HLA) complex, is
found on the outside of the plasma membrane. It is structurally related to the immunoglobulins.
This test measures ß 2-microglobulin, which is nonspecifically increased in inflammatory conditions and in active chronic
lymphatic leukemia. It may be used to differentiate glomerular from tubular dysfunction. In glomerular disease, ß
2 -microglobulin is increased in serum and decreased in urine, whereas in tubular disorders, it is decreased in serum and
increased in urine. In aminoglycoside toxicity, ß 2-microglobulin levels become abnormal before creatinine levels begin to
show abnormal values. Serum is also used to evaluate the prognosis of multiple myeloma.
Reference Values
Normal
Urine 24-hour specimen: <1 mg/day
Blood serum specimen: <2.7 µg/mL or <2.7 mg/L
Procedure
1. Collect a 24-hour urine specimen or a serum sample.
2. Keep the pH neutral or alkaline (pH > 6.0)
3. Freeze specimen if not analyzed immediately. Not stable at room temperature.
Clinical Implications
1. Increased urine ß 2-microglobulin occurs in:
a. Renal tubular disorders (>50 mg/day)
b. Heavy-metal poisoning (mercury, cadmium)
c. Drug toxicity (aminoglycosides, cyclosporine)
d. Fanconi's syndrome, Wilson's disease
e. Pyelonephritis
f. Renal allograft rejection
g. Lymphoid malignancies associated with B-lymphocyte lineage
h. Acquired immunodeficiency syndrome (AIDS) (can be used as a predictor of the progression to AIDS)
2. Increased serum ß 2-microglobulin occurs in:
a. Multiple myeloma (associated with a poor survival prognosis)
b. Renal dialysis
c. Amyloidosis
d. Viral infection
Interfering Factors
1.
2.
3.
4.

Acid urine—not stable, pH < 6.0
Certain antibiotics (eg, gentamicin, tobramycin)
Recent nuclear medicine scan
Increased synthesis in certain diseases (eg, Crohn's disease, hepatitis, sarcoidosis) decreases the usefulness of
the blood serum test.
5. Random specimens are not recommended.
Interventions
Pretest Patient Preparation
1. Instruct patient regarding the purpose of and procedure for test.
2. See instructions for 24-hour urine collection (see Long-Term, Timed Urine Specimen, page 171).
3. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately.

2. See Chapter 1 guidelines for safe, effective, informed posttest care .
Urine Glucose (Sugar)
Glucose is present in glomerular filtrate and is reabsorbed by the proximal convoluted tubule. If the blood glucose level
exceeds the reabsorption capacity of the tubules, glucose will appear in the urine. Tubular reabsorption of glucose is by
active transport in response to the body's need to maintain an adequate concentration of glucose. The blood level at
which tubular reabsorption stops is termed the renal threshold, which for glucose is between 160 and 180 mg/dL (9–10
mmol/L).
Types of Glucose Tests
1. Reduction tests (Clinitest)
a. These are based on reduction of cupric ions by glucose. When the compounds are added to urine, a heat
reaction takes place. This results in precipitation and a change in the color of the urine if glucose is present.
b. These tests are nonspecific for glucose because the reaction can also be caused by other reducing substances
in the urine, including:
1. Creatinine, uric acid, ascorbic acid
2. Other sugars, such as galactose, lactose, fructose, pentose, and maltose
c. These tests have a lower sensitivity than enzyme tests.
2. Enzyme tests (Clinistix, Diastix, Tes-Tape)
a. These tests are based on interaction between glucose oxidase (an enzyme) and glucose. When dipped into
urine, the enzyme-impregnated strip changes color according to the amount of glucose in the urine. The
manufacturer's color chart provides a basis for comparison of colors between the sample and the manufacturer's
control.
b. These tests are specific for glucose only.
Reference Values
Normal
Random specimen: Negative
24-hour specimen: 1–15 mg/dL (60–830 µmol/L) or <0.5 g/24 hours (<2.8 mmol/day)
Procedure
1. Use a freshly voided specimen.
2. Follow directions on the test container exactly. Timing must be exact; the color reaction must be compared with the
closest matching control color on the manufacturer's color chart to ascertain accurate results.
3. Record the results on the patient's record.
4. Refrigerate or ice the entire urine sample during collection if a 24-hour urine specimen is also ordered. See Table
3-3 for proper preservative.

Clinical Alert
1. Urine glucose > 1000 mg/dL (>55 mmol/L) (4+) is a critical value.
2. Determine exactly what drugs the patient is taking and whether the metabolites of these drugs can affect the
urine glucose results. Frequent updating in regard to the effects of drugs on blood glucose levels is necessary in
light of the many new drugs introduced and prescribed.
3. Test results may be reported as “plus” (+) or as percentages. Percentages are more accurate.
4. When screening for galactose (galactosuria) in infants, the reduction test must be used. The enzyme tests do not
react with galactose.
5. Newborns should always be tested by both methods (reduction and enzymatic).
Clinical Implications
1. Increased glucose occurs in:
a. Diabetes mellitus
b. Endocrine disorders (thyrotoxicosis, Cushing's syndrome, acromegaly)
c. Liver and pancreatic disease
d. Central nervous system disorders (brain injury, stroke)
e. Impaired tubular reabsorption
1. Fanconi's syndrome
2. Advanced renal tubular disease
f. Pregnancy with possible latent diabetes (gestational diabetes)
2. Increase of other sugars (react only with reduction tests, not dipstick tests):
a. Lactose—pregnancy, lactation, lactose intolerance
b. Galactose—hereditary galactosuria (severe enzyme deficiency in infants; must be treated promptly)
c. Xylose—excessive ingestion of fruit
d. Fructose—hereditary fructose intolerance, hepatic disorders
e. Pentose—certain drug therapies and rare hereditary conditions
Interfering Factors
1. Interfering factors for reduction test (false-positive results):
a. Presence of non–sugar-reducing substances such as ascorbic acid, homogentisic acid, creatinine
b. Tyrosine
c. Nalidixic acid, cephalosporins, probenecid, and penicillin

2.

3.
4.
5.
6.

d. Large amounts of urine protein (slows reaction)
Interfering factors for dipstick enzyme tests:
a. Ascorbic acid (in large amounts) may cause a false-negative result
b. Large amount of ketones may cause a false-negative result
c. Peroxide or strong oxidizing agents may cause a false-positive result.
Stress, excitement, myocardial infarction, testing after a heavy meal, and testing soon after the administration of
intravenous glucose may all cause false-positive results, most frequently trace reactions.
Contamination of the urine sample with bleach or hydrogen peroxide may invalidate results.
False-negative results may occur if urine is left to sit at room temperature for an extended period, owing to the rapid
glycolysis of glucose.
High specific gravity depresses color development, low specific gravity intensifies it. See Appendix J for other drugs
that affect test outcomes.

Interventions
Pretest Patient Preparation
1. Instruct the patient about the test purpose, the procedure, and the double-voiding technique.
a. Discard the first voided morning specimen, then void 30 to 45 minutes later for the test specimen. This second
specimen reflects the immediate state of glucosuria more accurately because the first morning specimen
consists of urine that has been present in the bladder for several hours.
b. Advise the patient not to drink liquids between the first and second voiding so as not to dilute the glucose
present in the specimen.
c. A urine glucose test combined with a blood glucose test gives a more complete assessment of diabetes.
2. Instruct the patient about the 24-hour urine collection procedure when applicable (see Long-Term, Timed Urine
Specimen, page 171).
3. Follow Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and counsel appropriately.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
Urine glucose > 1000 mg/dL (>55 mmol/L)—test blood glucose, notify physician, and begin appropriate treatment.
Urine Ketones (Acetone; Ketone Bodies)
Ketones, which result from the metabolism of fatty acid and fat, consist mainly of three substances: acetone,
ß-hydroxybutyric acid, and acetoacetic acid. The last two substances readily convert to acetone, in essence making
acetone the main substance being tested. However, some testing products measure only acetoacetic acid.
In healthy persons, ketones are formed in the liver and are completely metabolized so that only negligible amounts
appear in the urine. However, when carbohydrate metabolism is altered, an excessive amount of ketones is formed
(acidosis) because fat becomes the predominant body fuel instead of carbohydrates. When the metabolic pathways of
carbohydrates are disturbed, carbon fragments from fat and protein are diverted to form abnormal amounts of ketone
bodies. Increased ketones in the blood lead to electrolyte imbalance, dehydration, and, if not corrected, acidosis and
eventual coma.
The excess presence of ketones in the urine (ketonuria) is associated with diabetes or altered carbohydrate metabolism.
Some “fad” diets that are low in carbohydrates and high in fat and protein also produce ketones in the urine. Testing for
urine ketones in patients with diabetes may provide the clue to early diagnosis of ketoacidosis and diabetic coma.
Indications for Ketone Testing
1. General: Screening for ketonuria is frequently done in hospitalized patients, presurgical patients, pregnant women,
children, and persons with diabetes.
2. Glycosuria (diabetes):
a. Testing for ketones is indicated in any patient showing elevated urine and blood sugars.
b. When treatment is being switched from insulin to oral hypoglycemic agents, the development of ketonuria within
24 hours after withdrawal of insulin usually indicates a poor response to the oral hypoglycemic agents.
c. The urine of diabetic patients treated with oral hypoglycemic agents should be tested regularly for glucose and
ketones because oral hypoglycemic agents, unlike insulin, do not control diabetes when acute complications
such as infection develop.
d. Ketone testing is done to differentiate between diabetic coma–positive ketones and insulin shock–negative
ketones.
3. Acidosis:
a. Ketone testing is used to judge the severity of acidosis and to monitor the response to treatment.
b. Urine ketone measurement frequently provides a more reliable indicator of acidosis than blood testing (it is
especially useful in emergency situations).
c. Ketones appear in the urine before there is any significant increase of ketones in the blood.
4. Pregnancy: During pregnancy, the early detection of ketones is essential because ketoacidosis is a prominent
factor that contributes to intrauterine death.

Reference Values
Normal
Urine: Negative
Serum or plasma:
Acetone: <2.0 mg/dL or <0.34 mmol/L
Acetoacetate: <1 mg/dL or <0.1 mmol/L
ß-hydroxybutyric acid: 0.21–2.81 mg/dL or 20–270 µmol/L
Procedure
1. Dip the ketone reagent strip in fresh urine, tap off excess urine, time the reaction accurately, and then compare the
strip with the control color chart on the container.
2. Follow the manufacturer's directions exactly if procedure differs from the technique just described.
3. Do not use dipsticks to test for ketones in blood. Special testing products are designed for blood.
Clinical Implications
1. Ketosis and ketonuria may occur whenever increased amounts of fat are metabolized, carbohydrate intake is
restricted, or the diet is rich in fats (either “hidden” or obvious). This state can occur in the following situations:
a. Metabolic conditions
1. Diabetes mellitus (diabetic acidosis)
2. Renal glycosuria
3. Glycogen storage disease (von Gierke's disease)
b. Dietary conditions
1. Starvation, fasting
2. High-fat diets
3. Prolonged vomiting, diarrhea
4. Anorexia
5. Low-carbohydrate diet
6. Eclampsia
c. Increased metabolic states caused by:
1. Hyperthyroidism
2. Fever
3. Pregnancy or lactation
2. In nondiabetic persons, ketonuria occurs frequently during acute illness, severe stress, or strenuous exercise.
Approximately 15% of hospitalized patients have ketones in their urine even though they do not have diabetes.
3. Children are particularly prone to developing ketonuria and ketosis.
4. Ketonuria occurs after anesthesia (ether or chloroform).
Interfering Factors
1. Drugs that may cause a false-positive result include:
a. Levodopa
b. Phenothiazines
c. Ether
d. Insulin
e. Isopropyl alcohol
f. Metformin
g. Penicillamine
h. Phenazopyridine (Pyridium)
i. Captopril
2. False-negative results occur if urine stands too long, owing to loss of ketones into the air.
3. See Appendix J for other drugs that affect test outcomes.

Clinical Alert
Ketonuria signals a need for caution, rather than crisis intervention, in either a diabetic or a nondiabetic patient.
However, this condition should not be taken lightly.
1. In the diabetic patient, ketone bodies in the urine suggest that the diabetes is not adequately controlled and that
adjustments of either the medication or the diet should be made promptly.
2. In the nondiabetic patient, ketone bodies indicate a reduced carbohydrate metabolism and excessive fat
metabolism.
3. Positive urine ketones in a child younger than 2 years of age is a critical alert.
Interventions
Pretest Patient Preparation
1. Explain test purpose and procedure.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .

Urine Nitrite (Bacteria)
This test is a rapid, indirect method for detecting bacteria in the urine. Significant UTI may be present in a patient who
does not experience any symptoms. Common gram-negative organisms contain enzymes that reduce the nitrate in the
urine to nitrite.
Clinicians frequently request the urine nitrate test to screen high-risk patients: pregnant women, school-aged children
(especially girls), diabetic patients, elderly patients, and patients with a history of recurrent infections.
The majority of UTIs are believed to start in the bladder as a result of extreme contamination; if left untreated, they can
progress upward all the way to the kidneys. Pyelonephritis is a frequent complication of untreated cystitis and can lead to
renal damage. Detection of bacteria using the nitrate test and subsequent antibiotic therapy can prevent these serious
complications. The nitrate test can also be used to evaluate the success of antibiotic therapy.
Reference Values
Normal
Negative for bacteria
Procedure
1. Obtain a first morning specimen because urine that has been in the bladder for several hours is more likely to yield
a positive nitrate test than a random urine sample that may have been in the bladder for only a short time. A
clean-catch (midstream) urine specimen is needed to minimize bacterial contamination from adjacent areas.
2. Follow the exact testing procedure according to prescribed guidelines for reliable test results. Any shade of pink is
positive for nitrite-producing bacteria.
3. Compare the reacted reagent area on the dipstick with a white background to aid in the detection of a faint pink hue
that might otherwise be missed.
4. Perform a microscopic examination to verify results, if at all possible.
Clinical Implications
1. Under the light microscope, the presence of > 20 bacteria per high-power field (hpf) may indicate a UTI. Untreated
bacteriuria can lead to serious kidney disease.
2. The presence of a few bacteria suggests a UTI that cannot be confirmed or excluded until more definitive studies,
such as culture and sensitivity tests, are performed. Again, this finding merits serious consideration for treatment.
3. A positive nitrate test is a reliable indicator of significant bacteriuria and is a cue for performing urine culture.
4. A negative result should never be interpreted as indicating absence of bacteriuria, for the following reasons:
a. If an overnight urine sample is not used, there may not have been enough time for the nitrate to convert to nitrite
in the bladder.
b. Some UTIs are caused by organisms that do not convert nitrate to nitrite (eg, staphylococci, streptococci).
c. Sufficient dietary nitrate may not be present for the nitrate-to-nitrite reaction to occur.
Interfering Factors
1. Azo dye metabolites and bilirubin can produce false-positive results.
2. Ascorbic acid can produce false-negative results.
3. False-positive results can be obtained if the urine sits too long at room temperature, allowing contaminant bacteria
to multiply.
4. High specific gravity will reduce the sensitivity.

Clinical Alert
A negative urine nitrate test should never be interpreted as indicating the absence of bacteria.
Interventions
Pretest Patient Preparation
1. Explain the test purpose and urine specimen collection procedure. Instruct the patient in the procedure necessary
for a clean-catch (midstream) specimen.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .
Urine Leukocyte Esterase
Usually, the presence of leukocytes (WBCs) in the urine indicates a UTI. The leukocyte esterase test detects esterase
released by the leukocytes into the urine. This is a standardized means for the detection of WBCs.
Microscopic examination and chemical testing are used to determine the presence of leukocytes in the urine. The
chemical test is done with a leukocyte esterase dipstick. This test can also detect intact leukocytes, lysed leukocytes, and

WBC casts.
Reference Values
Normal
Negative
Procedures
1. Collect a fresh, random urine specimen with a clean-catch or midstream technique.
2. Follow directions for dipstick use exactly. Timing is critical for accurate results.
3. Note that a positive result causes a purple color on the dipstick. The test is not designed to measure the amount of
leukocytes.
Clinical Implications
1. Positive results are clinically significant and indicate:
a. Cystitis (UTI)
b. Acute pyelonephritis
c. Acute Bright's disease
d. Bladder tumor
e. Systemic lupus erythematosus (SLE)
f. Tuberculosis infection
2. Urine with positive results from the dipstick should be examined microscopically for WBCs and bacteria.
Interfering Factors
1. False-positive results
a. Vaginal discharge, parasites, histocytes
b. Drug therapies (eg, ampicillin, kanamycin)
c. Salicylate toxicity
d. Strenuous exercise
2. False-negative results
a. Large amounts of glucose or protein
b. High specific gravity
c. Certain drugs (eg, tetracycline)

Clinical Alert
A urine sample that tests positive for both nitrite and leukocyte esterase should be cultured for pathogenic bacteria.
Interventions
Pretest Patient Preparation
1. Explain test purpose and procedure.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Urine Bilirubin
Bilirubin is formed in the reticuloendothelial cells of the spleen and bone marrow as a result of the breakdown of
hemoglobin; it is then transported to the liver. Urinary bilirubin levels are increased to significant levels in the presence of
any disease process that increases the amount of conjugated bilirubin in the bloodstream (see Chap. 6). Elevated
amounts appear when the normal degradation cycle is disrupted by obstruction of the bile duct or when the integrity of
the liver is damaged.
Urine bilirubin aids in the diagnosis and monitoring of treatment for hepatitis and liver damage. Urine bilirubin is an early
sign of hepatocellular disease or intrahepatic or extrahepatic biliary obstruction. It should be a part of every UA because
bilirubin often appears in the urine before other signs of liver dysfunction (eg, jaundice, weakness) become apparent. Not
only does the detection of urinary bilirubin provide an early indication of liver disease, but also its presence or absence
can be used in determining the cause of clinical jaundice.
Reference Values
Normal
Negative (0–0.02 mg/dL or 0–0.34 µmol/L)
Procedure
1. Examine the urine within 1 hour of collection because urine bilirubin is unstable, especially when exposed to light. If
the urine is yellow-green to brown, shake the urine. If a yellow-green foam develops, bilirubin is probably present.
Bilirubin alters the surface tension and allows foam to form. The yellow color is the bilirubin.
2. Chemical strip testing:
a. Dip a chemically reactive dipstick into the urine sample according to the manufacturer's directions.

b. Close comparison of color changes on the dipstick with control colors on the color chart is an absolute
necessity. Failure to make a close approximation of color may result in failure to recognize urine bilirubin. Good
lighting is required.
c. Interpret results as “negative” to “3+” or as “small,” “moderate,” or “large” amounts of bilirubin.
3. When it is crucial to detect even very small amounts of bilirubin in the urine, as in the earliest phase of viral
hepatitis, Icotest tablets are preferred for testing because they are more sensitive to urine bilirubin. When elevated
amounts of urine bilirubin are present, a blue to purple color forms on the absorptive mat. The intensity of the color
and the rapidity of its development are directly proportional to the amount of bilirubin in the urine.
Clinical Implications
1. Even trace amounts of bilirubin are abnormal and warrant further investigation. Normally, there is no detectable
bilirubin in the urine.
2. Increased bilirubin occurs in:
a. Hepatitis and liver diseases caused by infections or exposure to toxic agents (cirrhosis)
b. Obstructive biliary tract disease
c. Liver or biliary tract tumors
d. Septicemia
e. Hyperthyroidism

NOTE
Urine bilirubin is negative in hemolytic disease.
Interfering Factors
1. Drugs may cause false-positive or false-negative results (see Appendix J).
2. Bilirubin rapidly decomposes when exposed to light; therefore, urine should be tested immediately.
3. High concentrations of ascorbic acid or nitrate cause decreased sensitivity.

Clinical Alert
Pyridium-like drugs or urochromes may give the urine an amber or reddish color and can mask the bilirubin reaction.
Interventions
Pretest Patient Preparation
1. Explain test purpose and procedure.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately for liver disease.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Urine Urobilinogen, Random and Timed
Bilirubin, which is formed from the degradation of hemoglobin, is transformed through the action of bacterial enzymes into
urobilinogen after it enters the intestines. Some of the urobilinogen formed in the intestine is excreted as part of the
feces, where it is oxidized to urobilin; another portion is absorbed into the portal bloodstream and carried to the liver,
where it is metabolized and excreted in the bile. Traces of urobilinogen in the blood that escape removal by the liver are
carried to the kidneys and excreted in the urine. This is the basis of the urine urobilinogen test. Unlike bilirubin,
urobilinogen is colorless.
Urine urobilinogen is one of the most sensitive tests available to determine impaired liver function. Urinary urobilinogen is
increased by any condition that causes an increase in the production of bilirubin and by any disease that prevents the
liver from normally removing the reabsorbed urobilinogen from the portal circulation. An increased urobilinogen level is
one of the earliest signs of liver disease and hemolytic disorders.
Although it cannot be determined by reagent strip, the absence of urobilinogen is also diagnostically significant and
represents an obstruction of the bile duct.
Reference Values
Normal
Random specimen: 0.1–1 Ehrlich U/dL or <1 mg/dL
2-hour specimen: 0.1–1.0 Ehrlich U/2 hours or <1 mg/2 hours
24-hour specimen: 0.5–4.0 Ehrlich U/24 hours or 0.5–4.0 mg/day
Procedure
1. Follow instructions for collecting a timed 24-hour, 2-hour, or random specimen. Check with the laboratory for
specific protocols.
2. Perform the 2-hour timed collection from 1:00 p.m. to 3:00 p.m. (1300 to 1500) or from 2:00 p.m. to 4:00 p.m. (1400
to 1600) for best results because peak excretion occurs during this time. No preservatives are necessary. Record
the total amount of urine voided. Protect the collection receptacle from light. Test immediately after specimen

collection is completed.
Clinical Implications
1. Urine urobilinogen is increased when there is:
a. Increased destruction of RBCs
1. Hemolytic anemias
2. Pernicious anemia (megaloblastic)
3. Malaria
b. Hemorrhage into tissues
1. Pulmonary infarction
2. Excessive bruising
c. Hepatic damage
1. Biliary disease
2. Cirrhosis (viral and chemical)
3. Acute hepatitis
d. Cholangitis
2. Urine urobilinogen is decreased or absent when normal amounts of bilirubin are not excreted into the intestinal
tract. This usually indicates partial or complete obstruction of the bile ducts. The stool is pale in color. Decreased
urinary urobilinogen is associated with:
a. Cholelithiasis
b. Severe inflammation of the biliary ducts
c. Cancer of the head of the pancreas
3. During antibiotic therapy, suppression of normal gut flora may prevent the breakdown of bilirubin to urobilinogen;
therefore, urine levels will be decreased or absent.
4. More comprehensive information is obtained when the tests for urobilinogen and bilirubin are correlated (see Table
3.5 for comparisons).

Table 3.5 Comparison of Urine Urobilinogen and Urine Bilirubin Values
Test

In Health In Hemolytic Disease In Hepatic Disease In Biliary Obstruction

Urine urobilinogen Normal Increased
Urine bilirubin
Negative Negative

Increased
Low or absent
Positive or negative Positive

Clinical Alert
Urine urobilinogen rapidly decomposes at room temperature or when exposed to light.
Interfering Factors
1. Drugs that may affect urobilinogen levels include those that cause cholestasis and those that reduce the bacterial
flora in the gastrointestinal tract. Check with the pharmacist for specific drugs patient is taking.
2. Peak excretion is known to occur from noon to 4:00 p.m. The amount of urobilinogen in the urine is subject to
diurnal variation.
3. Strongly alkaline urine shows a higher urobilinogen level, and strongly acidic urine shows a lower urobilinogen
level.
4. Drugs that may cause increased urobilinogen include drugs that cause hemolysis. Check with the pharmacist for
specific drugs the patient is taking.
5. If the urine is highly colored, the strip will be difficult to read.
Interventions
Pretest Patient Preparation
1. Explain test purpose and urine collection procedures.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately for anemia and gastrointestinal disorders. Advise concerning
need for follow-up testing.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .

MICROSCOPIC EXAMINATION OF URINE SEDIMENT
In health, the urine contains small numbers of cells and other formed elements from the entire genitourinary tract: casts
and epithelial cells from the nephron; epithelial cells from the kidney, pelvis, ureters, bladder, and urethra; mucous
threads and spermatozoa from the prostate; and possibly RBCs or WBCs and an occasional cast. In renal parenchymal
disease, the urine usually contains increased numbers of cells and casts discharged from an organ that is otherwise
accessible only by biopsy or surgery ( Table 3.6). Urinary sediment provides information useful for both diagnosis and
prognosis. It provides a direct sampling or urinary tract morphology.

Table 3.6 Microscopic Examination of Urine Sediment
Urine Sediment Component Clinical Significance
Bacteria
Casts
Broad casts
Epithelial (renal) casts
Fatty casts
Granular
Waxy
Hyaline casts
Red blood cell casts
White blood cell casts
Epithelial cells
Renal cells
Squamous cells
Erythrocytes
Fat bodies (oval)
Leukocytes

Urinary tract infection
Tubular or glomerular disorders
Formation occurs in collecting tubules; serious kidney disorder, extreme stasis of flow
Tubular degeneration
Nephrotic syndrome
Renal parenchymal disease
Stasis of flow
Chronic renal failure, chronic renal disease, congestive heart failure; stress or exercise
Acute glomerulonephritis
Pyelonephritis, acute interstitial nephritis
Damage to various parts of urinary tract
Tubular damage
Normal or contamination
Most renal disorders, menstruation; strenuous exercise
Nephrotic syndrome
Most renal disorders; urinary tract infection; pyelonephritis

The urinary sediment is obtained by pouring 1 mL of fresh, well-mixed urine into a conical tube and centrifuging the
sample at a specific speed for 10 minutes. The supernatant is poured off, and 1 mL of the sediment is resuspended. A
small drop is placed on a slide, cover-slipped, and examined microscopically.
The urine sediment can be broken down into cellular elements (RBCs, WBCs, and epithelial cells), casts, crystals, and
bacteria. These may originate anywhere in the urinary tract. When casts do occur in the urine, they may indicate tubular
or glomerular disorders.
Casts are the only elements found in urinary sediment that are unique to the kidneys. They are formed primarily within
the lumen of the distal convoluted tubule and collecting duct, providing a microscopic view of conditions within the
nephron. Their shapes are representative of the tubular lumen.
Cast width is significant in determining the site of origin and may indicate the extent of renal damage. The width of the
cast indicates the diameter of the tubule responsible for its formation. Cast width is described as narrow (as wide as 1 to
2 RBCs), medium-broad (3 to 4 RBCs), or broad (5 RBCs). The broad casts form in the collecting tubule and may be of
any composition. Their presence usually indicates a marked reduction in the functional capacity of the nephron and
suggests severe renal damage or end-stage renal disease.
The major constituent of casts is Tamm-Horsfall protein, a glycoprotein excreted by the renal tubular cells. It is found in
normal and abnormal urine and is not detected by the urine dipstick method.

Clinical Alert
Microscopic examination of urine sediment can provide the following information:
1. Evidence of renal disease as opposed to infection of the lower urinary tract.
2. Type and status of a renal lesion or disease.

An 82-year-old female resident displayed the following signs and symptoms related to a urinary tract infection: high fever
(101.0°F) for 24 hours; lethargy past 2 days; cloudy, foul-smelling urine; and dysuria. Urinalysis microscopic exam and
culture sensitivity were ordered.
URINALYSIS
Interpretation of test results for routine urinalysis and urine culture with interventions.
Urinalysis Report:
Macroscopic Analysis Normal
Date: 06/16/03 Time: 2130
Color
Pale yellow-amber
Yellow
Clarity
Clear to slightly hazy Cloudy *
Urine chemistries
Specific gravity
1.005–1.030
1.0–2.0 *
Glucose
Negative
Negative
Ketones
Negative
Negative
pH
5.0–8.0
8.5 High
Protein
Negative
30 *
Blood
Negative
Small *
Bilirubin
Negative
Negative

Urobilinogen
0.2–1.0 EU/dL
0.2
Nitrite
Negative
Pos *
Leukocyte ester
Negative
Small
Microscopic examination
BACT/hpf
None
4+ *
WBC/hpf
0–2
50–100
RBC/hpf
0–2
2–5 *
SQ EPITH/lpf
0–2
10–20 *
Casts/lpf
None
Present *
Hyaline/lpf
Occasional
2–5 *
Triple Phos
None
Few *(occurs in alkaline, neutral, or slightly acid urine)
* = abnormal, HPF = high-powered field, LPF = low-powered field, NEG = negative, BACT = bacteria, WBC = white blood
cells, RBC = red blood cells, SPEC = specific (as in specific gravity), POS = positive, TRC = trace, ABN = abnormal, EU
= Ehrlich units, MIC = minimum inhibitory concentration (the lowest concentration of the antibiotic that inhibits the
organism's growth), S = sensitive or susceptible, R = resistant, TMP-SMX = trimethoprim sulfamethoxazole

Urine Culture Antibiotic Drug Sensitivity and Organism Susceptibility
Collected: 06/16/03—Time 2130
Received: 06/17/03—Time 1006
Final Report—6/19/03 of antibiotic drug sensitivity and organism susceptibility
>100,000 colonies/mL Streptococcus agalactiae, Group B hemolytic
>100,000 colonies/mL Escherichia coli
Susceptibility Testing— E. coli
S = sensitivity or susceptibility; R = resistant; TMP-SMX = trimethoprim sulfamethoxazole
Susceptibility Interpretation of
Minimum Inhibitory Concentration (MIC) (the lowest
Organism Susceptibility to Antibiotic concentration of antibiotic that inhibits the organism's
growth)
Ampicillin
S
2
Piperacillin
S
<8
Ampicill/Sulbac
S
= 8/4
Cefazolin
S
<8
Gentamicin
S
=1
Tobramycin
S
=1
Tetracycline
S
2
Ciprofloxacin
S
=1
Levofloxacin
S
<2
Nitrofurantoin
S
< 32
TMP-SMX
S
= 5/9.5
Bactrim
Results of the tests were abnormal outcomes and the following interventions started on 06/19/03 with Bactrim DS
(double strength) BID × 7 days; then Bactrim SS (single strength) every day until further orders; force fluids as
appropriate. Repeat urinalysis and culture and sensitivity in 2 weeks. The rationale for Bactrim as drug of choice was
because of both sensitivity and MIC (see legend).

Urine Red Blood Cells and Red Blood Cell Casts
In health, erythrocytes (RBCs) occasionally appear in the urine. However, persistent findings of even small numbers of
RBCs should be thoroughly investigated because these cells come from the kidney and may signal serious renal
disease. They are usually diagnostic of glomerular disease.
Reference Values
Normal
RBCs: 0–3/hpf (high-power field)
RBC casts: 0/lpf (low-power field)
Procedure for Microscopic Urine Examination
1. Collect a random urine specimen. Transport the specimen to the laboratory as soon as possible.
2. Urinary sediment is microscopically examined under both the low-power field (lpf) and the high-power field (hpf).
Low power is used to find and count casts; RBCs, WBCs, and bacteria show up and are counted under high power.
Amounts present are defined in the following terms: few, moderate, packed, and packed solid; or 1+, 2+, 3+, and
4+. Crystals and other elements are also noted.
3. Microscopic results should be correlated with the physical and chemical findings to ensure the accuracy of the
report ( Table 3.7).

Table 3.7 Common Correlations in Urinalysis
Microscopic Elements Physical Examination
Red blood cells
White blood cells

Epithelial cast cells
Bacteria

Crystals
*Positive result.

Dipstick Measurement *

Turbidity, red to brown color Blood
Turbidity
Protein
Nitrite
Leukocytes
Turbidity
Protein
Turbidity, odor
pH
Nitrite
Leukocytes
Turbidity, odor
pH

Clinical Implications
1. RBC casts indicate hemorrhage in the nephron.
a. RBC casts are found in three forms:
1. Intact RBCs
2. Degenerating cells within a protein matrix
3. Homogenous blood casts (“hemoglobin casts”)
b. RBC casts indicate acute inflammatory or vascular disorders in the glomerulus and are found in:
1. Glomerulonephritis (acute and chronic)
2. Renal infarction
3. Lupus nephritis
4. Goodpasture's syndrome
5. Severe pyelonephritis
6. Congestive heart failure
7. Renal vein thrombosis
8. Acute bacterial endocarditis
9. Malignant hypertension
10. Periarteritis nodosa
c. RBCs should be present if RBC casts are in the sediment.
2. Red blood cells
a. The finding of more than 1 or 2 RBCs/hpf is abnormal and can indicate:
1. Renal or systemic disease (glomerulonephritis)
2. Trauma to the kidney (vascular injury)
b. Increased numbers of RBCs occur in:
1. Pyelonephritis
2. Systemic lupus erythematosus (SLE)
3. Renal stones
4. Cystitis (acute or chronic)
5. Prostatitis
6. Tuberculosis (renal)
7. Genitourinary tract malignancies
8. Hemophilia, coagulation disorders
9. Malaria
10. Polyarteritis nodosa
11. Malignant hypertension
12. Acute febrile episodes
c. Greater numbers of RBCs than WBCs indicate bleeding into the urinary tract, as may occur with:
1. Trauma
2. Tumors of rectum, colon, pelvis
3. Aspirin overdose or other toxic drugs
4. Anticoagulant therapy overdose
5. Thrombocytopenia

Clinical Alert
1. In health, RBCs are occasionally found in the urine. However, persistent findings of even small numbers of RBCs
should be thoroughly investigated, the first step being to request a fresh urine specimen for repeat testing.
2. Rule out the possible presence of menstrual blood, vaginal bleeding, or trauma to the perineal area in a female
patient.
Interfering Factors
1. Increased numbers of RBCs may be found after a traumatic catheterization and after passage of urinary tract or
kidney stones.
2. Alkaline urine hemolyzes RBCs and dissolves casts (“ghosts”).
3. Some drugs can cause increased numbers of RBCs in the urine (see Appendix J).
4. RBC casts and RBCs may appear after very strenuous physical activity or participation in contact sports.
5. Heavy smokers show small numbers of RBCs in the urine.
6. Yeast or oil droplets may be mistaken for RBCs.

Interventions
Pretest Patient Preparation
1. Explain test purpose and procedure for random urine sample collection.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and counsel appropriately.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Urine White Blood Cells and White Blood Cell Casts
Leukocytes (WBCs) may originate from anywhere in the genitourinary tract. They are also capable of amoeboid migration
through the tissues to sites of infection or inflammation. An increase in urinary WBCs is called pyuria and indicates the
presence of an infection or inflammation in the genitourinary system. However, WBC casts always come from the kidney
tubules.
Reference Values
Normal
WBCs: 0–4/hpf
Normal women may have slightly more WBCs.
WBC casts: 0/lpf
Procedure
1. Collect a random urine specimen and transport it to the laboratory as soon as possible.
2. Urinary sediment is microscopically examined under high power for cells and under low power for casts.
Clinical Implications
1. White blood cells
a. Large numbers of WBCs (>30/hpf) usually indicate acute bacterial infection within the urinary tract.
b. Increased WBCs are seen in:
1. All renal disease
2. Urinary tract disease (eg, cystitis, prostatitis urethritis)
3. Appendicitis, pancreatitis
4. Strenuous exercise
5. Chronic pyelonephritis
6. Bladder tumors
7. Tuberculosis
8. Lupus erythematosus
9. Interstitial nephritis
10. Glomerulonephritis
c. In bladder infections, WBCs tend to be associated with bacteria, epithelial cells, and relatively few RBCs.
d. Large numbers of lymphocytes and plasma cells in the presence of a kidney transplant may indicate early tissue
rejection (acute renal allograft rejection).
e. Eosinophils are associated with tubulointerstitial disease and hypersensitivity to penicillin.
f. WBC clumps suggest renal origin of WBCs and should be reported when present.
2. WBC casts
a. WBC casts indicate renal parenchymal infection and may occur in:
1. Pyelonephritis (most common cause)
2. Acute glomerulonephritis
3. Interstitial nephritis
4. Lupus nephritis
b. It can be very difficult to differentiate between WBC casts and epithelial cell casts.

Clinical Alert
A urine culture (see Chap. 7) should be done if elevated urine WBCs are found.
Interfering Factors
Vaginal discharge can contaminate a specimen with WBCs. Either a clean-catch urine specimen or a catheterized urine
specimen should be obtained to rule out contamination as the cause for WBCs in the urine.

Clinical Alert
Pyelonephritis may remain completely asymptomatic even though renal tissue is being progressively destroyed.
Therefore, careful examination (using low power) of urinary sediment for leukocyte casts is vital.
Interventions
Pretest Patient Preparation
The pretest care is the same as for the urine RBC test.
Posttest Patient Aftercare
The posttest care is the same as for the urine RBC test.

Urine Epithelial Cells and Epithelial Casts
Renal epithelial cell casts are formed from cast-off tubule cells that slowly degenerate, first into coarse and then into fine
granular material. Epithelial casts are the most rare casts.
Urine epithelial cells are of three kinds:
1. Renal tubule epithelial cells are round and slightly larger than WBCs. Each cell contains a single large nucleus.
These are the types of epithelial cells associated with renal disease. However, the presence of an occasional renal
epithelial cell is not unusual because the renal tubules are continually sloughing old cells. In cases of acute tubular
necrosis, renal tubular epithelial cells containing large nonlipid vacuoles may be seen. These are referred to as
bubble cells. When lipids cross the glomerular membrane, the renal epithelial cells absorb the lipids and become
highly refractive. These are called oval fat bodies. Both of these findings are significant and should be reported.
2. Bladder epithelial cells are larger than renal epithelial cells. They range from round to pear-shaped to columnar.
Also known as “transitional” epithelial cells, they line the urinary tract from the renal pelvis to the proximal two thirds
of the urethra.
3. Squamous epithelial cells are large, flat cells with irregular borders, a single small nucleus, and abundant
cytoplasm. Most of these cells are urethral and vaginal in origin and do not have much diagnostic importance.
Reference Values
Normal
Renal tubule epithelial cells: 0–3/hpf
Squamous epithelial cells are common in normal urine sample.
Renal tubule epithelial casts: 0 (not seen)
Procedure
1. Collect a random urine specimen.
2. Examine the urine sediment microscopically.
Clinical Implications
1. Epithelial cell casts are found when they are also present in the urine after exposure to toxic agents or viruses.
2. Renal tubular epithelial cells are found in:
a. Acute tubular necrosis
b. Acute glomerulonephritis (secondary effects)
c. Pyelonephritis
d. Salicylate overdose (toxic reaction)
e. Impending allograft rejection
f. Viral infections (eg, cytomegalovirus)
g. Poisoning from heavy metals or other toxins
Urine Hyaline Casts
Hyaline casts are clear, colorless casts that are formed when a renal protein within the tubules (Tamm-Horsfall protein)
precipitates and gels. Tamm-Horsfall protein is excreted at a fairly constant rate by the tubule cells and provides
immunologic protection from infection. Hyaline casts can be seen in physiologic states such as strenuous exercise and
even in the mildest renal disease. They are not associated with any one particular disorder.
Reference Values
Normal
Occasional (0–2/lpf)
Procedure
1.
2.
3.
4.

Obtain a fresh urine sample.
Examine urinary sediment microscopically for casts under low power.
Examine casts when the light intensity is reduced because they are colorless and transparent.
Note that wrinkling and convoluting of the cast occurs as it ages.

Clinical Implications
1. Hyaline casts indicate possible damage to the glomerular capillary membrane. These casts appear in:
a. Glomerulonephritis, pyelonephritis
b. Malignant hypertension
c. Chronic renal disease
d. Congestive heart failure
e. Diabetic nephropathy
2. Hyaline casts may be a temporary phenomenon in the presence of:
a. Fever (dehydration)
b. Postural orthostatic lordotic strain
c. Emotional stress
d. Strenuous exercise
e. Heat exposure
3. Nephrotic syndrome may be suspected when large numbers of hyaline casts appear in the urine together with
significant proteinuria, fine granular casts, fatty casts, oval bodies, or fat droplets.

4. In cylindroiduria, large numbers of hyaline casts may be present, but protein in the urine is absent. Cylindroids are
hyaline casts that have been formed at the junction of the ascending loop of Henle and therefore have tapered
ends.

Clinical Alert
Casts may not be found even when proteinuria is significant if the urine is dilute (1.010 SG) or alkaline. In these cases,
the casts are dissolved as soon as they are formed.
Interventions
The pretest and posttest care are the same as for the urine RBC test.
Urine Granular Casts
Granular casts appear homogeneous, coarsely granular, colorless, and very dense. They then further degenerate into
finely granular casts. It is not necessary to distinguish the different granular casts. Granular casts may result from
degradation of cellular casts, or they may represent direct aggregation of serum proteins into a matrix of Tamm-Horsfall
microprotein.
Reference Values
Normal
Occasional (0–2/lpf)
Procedure
1. Collect a random urine specimen and transport it to the laboratory as soon as possible.
2. Examine urinary sediment microscopically under low power.
Clinical Implications
1. Granular casts are found in:
a. Acute tubular necrosis
b. Advanced glomerulonephritis
c. Pyelonephritis
d. Malignant nephrosclerosis
2. Granular casts are found with hyaline casts after strenuous exercise or severe stress.
Interventions
The pretest and posttest care are the same as for the urine RBC test.
Urine Waxy Casts or Broad Casts (Renal Failure Casts) and Fatty Casts
Casts are formed in the collecting tubules under conditions of extreme renal stasis. Waxy casts form from the
degeneration of granular casts.
Broad, waxy casts are 2 to 6 times the width of ordinary casts and appear waxy and granular. Casts may vary in size as
disease distorts the tubular structure (they get wider because they are a mold of the tubules). Also, as urine flow from the
tubules becomes compromised, casts are more likely to form. The finding of broad, waxy casts suggests a serious
prognosis—hence, the term renal failure casts.
Fatty casts are formed from the attachment of fat droplets and degenerating oval fat bodies into a protein matrix. Fatty
casts are highly refractile and contain yellow-brown fat droplets, or oval fat bodies.
Reference Values
Normal
Negative (not seen)
Procedure
Examine urine sediment microscopically under low power.
Clinical Implications
1. Broad and waxy casts occur in:
a. Severe renal failure
b. Tubular inflammation and degeneration (nephrotic syndrome)
c. Localized nephron obstruction (extreme stasis of urine flow)
d. Malignant hypertension
e. Renal amyloidosis
f. Diabetic nephropathy
g. Renal allograft rejection
2. Fatty casts are found in:
a. Disorders causing lipiduria, such as nephrotic syndrome and lipoid nephrosis
b. Chronic glomerulonephritis
c. Kimmelstiel-Wilson syndrome
d. Lupus
e. Toxic renal poisoning

Clinical Alert
The presence of broad, waxy casts signals very serious renal disease.
Interventions
The pretest and posttest care are the same as for the urine RBC test.
Urine Crystals
A variety of crystals may appear in the urine. They can be identified by their specific appearance and solubility
characteristics. Crystals in the urine may present no symptoms, or they may be associated with the formation of urinary
tract calculi and give rise to clinical manifestations associated with partial or complete obstruction of urine flow.
The type and quantity of crystalline precipitate varies with the pH of the urine. Amorphous crystalline material has no
significance and forms as normal urine cools.
Procedure
1.
2.
3.
4.

Collect a random urine specimen. Crystal identification should be done on freshly voided specimens.
Examine the urinary sediment microscopically under high power.
The pH of the urine is an important aid to identification of crystals and must be noted.
The problems associated with the identification of abnormal crystals can be resolved by a check on the medications
the patient is receiving, saving considerable time and energy.

Clinical Implications Table 3.8 describes the meaning of urine crystal findings.
Table 3.8 Urine Crystals
Type of
Crystal
Acid Urine
Amorphous
urates
Uric acid

Color

Shape

Clinical Implications

Pink to brick red

Granules

Normal

Yellow-brown

Polymorphous—whetstones, rosettes or Normal; increased purine metabolism, gout,
prisms, rhombohedral prisms,
Lesch-Nyhan syndrome
hexagonal plate
Fan of slender prisms
No clinical significance

Sodium urate Colorless to
yellow
Cystine (rare) Colorless, highly
refractile
Cholesterol Colorless
(rare)
Leucine
Yellow or brown,
(rare)
highly refractile
Tyrosine
Colorless or
(rare)
yellow
Bilirubin
Reddish-brown

Flat hexagonal plates with well-defined
edges, singly or in clusters
“Broken window panes” with notched
corners
Spheroids with striations; pure form
hexagonal
Fine, silky needles in sheaves or
rosettes
Cubes, rhombic plates, amorphous
needles
Acid, Neutral, or Slightly Alkaline Urine
Calcium
Colorless
Octahedral dumbbells, often
oxalate
small—use high power

Hippuric acid Colorless
Rhombic plates, four-sided prisms
(rare)
Alkaline, Neutral, or Slightly Acid Urine
Triple
Colorless
“Coffin lids,” 3–6 sided prism;
phosphate
occasionally fern-leaf
Alkaline Urine
Calcium
Colorless
Needles, spheres, dumbbells
carbonate
Ammonium Yellow opaque
“Thorn apple” spheres, dumbbells,
biurate
brown
sheaves of needles
Calcium
Colorless
Prisms, plates, needles
phosphate
Amorphous White
Granules
phosphates

Cystinuria; cystinosis—cystine stones in
kidney, crystals also in spleen and eyes
Nephritis, nephrotic syndrome, chyluria
Protein breakdown, severe liver disease,
Fanconi's syndrome
Protein breakdown, severe liver disease,
oasthouse urine disease, tyrosinosis
Elevated bilirubin

Normal; large amounts in fresh urine may
indicate severe chronic renal disease, liver
disease, ethylene glycol poisoning, diabetes
mellitus, large doses of vitamin C
No significance

Urine stasis and chronic cystitis, chronic
pyelitis and enlarged prostate
Normal
Normal
Normal
Normal

Clinical Alert
Specific drugs (most commonly, ampicillin and sulfonamides) can cause increased levels of their own crystals, which
could be a sign of improper hydration.
Interfering Factors
1. Refrigerated urine will precipitate out many crystals because the solubility properties of the compound are altered.
2. Urine left standing at room temperature will also cause precipitation of crystals or the dissolving of the crystals.
3. Radiographic dye can cause crystals in improperly hydrated patients. These resemble uric acid crystals and can be
suspected in specimens that have an abnormally high specific gravity (>1.030).
Interventions
Patient Preparation and Aftercare
The pretest and posttest care are the same as for the urine RBC test.
Urine Shreds
Shreds consist of a mixture of mucus, pus, and epithelial (squamous) cells. They can be seen on gross examination.
Procedure
1. Examine a fresh urine specimen by visually checking for a hazy mass.
2. Centrifuge the specimen and examine the sediment microscopically to verify the presence of formed elements (
Table 3.9).

Table 3.9 Interpreting Urine Laboratory Findings
Disease
Acute
glomerulonephritis

Cause

Laboratory Findings Signs

Anti-basement membrane
Rapid appearance of
antibodies associated with
hematuria, proteinuria,
strep infection, variety of
and casts
infectious agents, toxins,
Varying degree of
allergens
hypertension, renal
Inflammation of the glomeruli insufficiency, and
by which they become
edema
abnormally permeable and
Frequently seen in
leak plasma proteins and
children and young
blood into the renal tubules
adults
Chronic
Represents end-stage result of Symptoms include
glomerulonephritis persistent glomerular damage edema, hypertension,
with continuing and
anemia, metabolic
irreversible loss of renal
acidosis, oliguria
function
progressing to anuria
Progress to end-stage renal
disease
Nephrotic syndrome Glomeruli whose basement
Massive protein,
membrane has become highly edema, high levels of
permeable to plasma proteins serum lipids, and low
of large molecular weight and levels of serum
lipids, allowing them to pass in albumin
the tubules
Acute tubular
Destruction of renal tubular
Oliguria and complete
necrosis
epithelial cells
renal failure
Usually following a
hypotensive event (shock),
toxic element, or drugs and
heavy metals
Cystitis (lower
Infection of the bladder most Frequent and painful
urinary tract)
commonly caused by bacteria; urination
Urethritis (urethra in Escherichia coli most common
males)
(85%)

Chemical
Findings

Microscopic
Findings

Gross
hematuria,
turbid,
smoky

Protein <1.0
g/dL
Blood
positive

Increased RBC,
WBC, renal
tubular epithelial
Casts: RBC,
granular, waxy,
broad

Hematuria

Protein >2.5
g/dL
Blood, small
amount
SG low and
fixed

Increased RBC,
WBC, renal
epithelial
Casts: granular,
waxy, broad

Cloudy

Protein >3.5
g/dL
Blood, small
amount

Increased RBC,
oval fat bodies,
free fat, renal
epithelial
Casts: fatty,
waxy, renal
Slightly
Protein <1.0 Increased RBC,
cloudy
g/dL
WBC, renal
Blood
epithelial
positive
Casts: renal,
SG low
granular, waxy,
broad
Cloudy, foul Protein <0.5 Increased WBC,
smelling
g/dL
bacteria, RBC,
Blood, small transitional
amount
epithelial
Nitrite
positive
(usually)
Leukocyte
esterase
positive
(usually)

Acute pyelonephritis An infection of the kidney or
More frequently in
Turbid, foul
(upper urinary tract) renal pelvis
women with repeated smelling
Caused by infectious organism urinary tract infections
that has traveled through the
urinary tract and invaded the
kidney tissue

Chronic
pyelonephritis

Permanent scarring of the
renal tissue

Polyuria and nocturia
develop as tubular
function is lost
With disease
progression, there is
hypertension and
altered renal and
glomerular flow

Cloudy

Acute interstitial
nephritis

Inflammation of the renal
interstitium caused by drug
toxicity or an allergic reaction

Fever, eosinophilia
Skin rash

Cloudy

Protein <1.0
g/dL
Blood
positive
Nitrite
positive
(usually)
Leukocyte
esterase
positive
(usually)
Protein <2.5
g/dL
Nitrite
positive
(usually)
Leukocyte
esterase
positive
(usually)
SG low
Protein <1
g/dL
Blood
positive
Leukocyte
esterase
positive
(usually)

Increased WBC
(clumps),
bacteria, renal
epithelial
Casts: WBC,
granular, renal
occasionally
waxy

Increased WBC
Casts: granular,
waxy, broad

Increased WBC,
RBC,
eosinophils,
epithelial
Increased casts:
granular, renal
hyaline

SG, specific gravity.
Adapted from Finnegan K: Routine urinalysis. In Lehmann CA, (ed): Saunders Manual of Clinical Laboratory Science.
Philadelphia, W. B. Saunders, 1998.

Clinical Implications
1.
2.
3.
4.

When mucus predominates, the shreds float on the surface.
When epithelial cells predominate, the shreds occupy the middle zone.
When pus (WBCs) predominates, the shreds are drawn to the bottom of the specimen.
Other findings in urine caused by specimen contamination include microscopic yeast, Trichomonas, spermatozoa,
vegetable fibers, parasites, and meat fibers. These should be reported because they have clinical significance.
a. Yeast may indicate urinary moniliasis or vaginal moniliasis ( Candida albicans)
b. Parasites—usually from fecal or vaginal contamination
c. Spermatozoa—seen after sexual intercourse, after nocturnal emissions, or in the presence of prostatic disease

URINE CHEMISTRY
Urine Pregnancy Test; Human Chorionic Gonadotropin (hCG) Test
From the earliest stage of development, the placenta produces hormones, either on its own or in conjunction with the
fetus. The very young placental trophoblast produces appreciable amounts of the hormone human chorionic
gonadotropin (hCG), which is excreted in the urine. This hormone is not found in the urine of men or of normal, young,
nonpregnant women.
Increased urinary hCG levels form the basis of the tests for pregnancy; hCG is present in blood and urine whenever
there is living chorionic/placental tissue. hCG is made up of a- and ß-subunits. The ß-subunit is the most sensitive and
specific test for early pregnancy. hCG can be detected in the urine of pregnant women 26 to 36 days after the first day of
the last menstrual period (ie, 5 to 7 days after conception). Pregnancy tests should return to negative 3 to 4 days after
delivery.
Reference Values
Normal
Positive: pregnancy exists
Negative: nonpregnant state
Procedure
1. Collect an early morning urine specimen. The first morning specimen generally contains the greatest concentration
of hCG. A random specimen may be used, but the SG must be more than 1.005.
2. Do not use grossly bloody specimens. If necessary, a catheterized specimen should be used.
Clinical Implications
1. A positive result usually indicates pregnancy.
2. Positive results also occur in

a. Choriocarcinoma
b. Hydatidiform mole
c. Testicular and trophoblastic tumors in males
d. Chorioepithelioma
e. Chorioadenoma destruens
f. About 65% of ectopic pregnancies
3. Negative or decreased results occur in
a. Fetal demise
b. Abortion, threatened abortion (test remains positive for 1 week after procedure)
Interfering Factors
1. False-negative test results and falsely low levels of hCG may be caused by dilute urine (low SG) or by using a
specimen obtained too early in pregnancy.
2. False-positive tests are associated with
a. Proteinuria
b. Hematuria
c. The presence of excess pituitary gonadotropin
d. Certain drugs (eg, chlorpromazine, phenothiazines, methadone)
Urine Estrogen, Total and Fractions (Estradiol [E 2 ] and Estriol [E 3]), 24-Hour Urine and Total Estrogen—Blood
Estradiol is the most active of the endogenous estrogens. The test evaluates female menstrual and fertility problems. In
men, estradiol is useful for evaluating estrogen-producing tumors. Estriol is the prominent urinary estrogen in pregnancy.
Serial measurements reflect the integrity of the fetal-placental complex.
Total estrogens evaluate ovarian estrogen-producing tumors in premenarchal or postmenopausal females.
These measurements, together with the gonadotropin (follicle-stimulating hormone [FSH]) level (see Chap. 6), are useful
in evaluating menstrual and fertility problems, male feminization characteristics, estrogen-producing tumors, and
pregnancy. Estradiol (E 2) is the most active of the endogenous estrogens. Estriol (E 3) levels in both plasma and urine
rise in pregnancy advances; significant amounts are produced in the third trimester. E 3 is no longer considered useful
for detection of fetal distress. Total estrogens may be helpful to establish time of ovulation and the optimum time for
conception.
Reference Values
Normal
Normal values vary widely between women and men and in the presence or pregnancy, the menopausal state, or the
follicular, ovulatory, or luteal stage of the menstrual cycle.
Urine Estradiol (E 2)
Men:
0–6 µg/24 hours or 0–22 nmol/day
Women: Follicular phase, 0–3 µg/24 hours or 0–11 nmol/day
Ovulatory peak, 4–14 µg/24 hours or 15–51 nmol/day
Luteal phase, 4–10 µg/24 hours or 15–37 nmol/day
Postmenopausal, 0–4 µg/24 hours or 0–15 nmol/day

Urine Estriol (E 3 ) (wide range of normal)
Men:
Women:

Pregnancy:
2nd trimester, 800–12,000 µg/24 hours or 2900–44,000
nmol/day

1–11 µg/24 hours or 4–40 nmol/day
Follicular phase, 0–14 µg/24 hours or 0–51 nmol/day
Ovulatory phase, 13–54 µg/24 hours or 48–198 nmol/day
Luteal phase, 8–60 µg/24 hours or 29–220 nmol/day
Postmenopausal, 0–11 µg/24 hours or 0–40 nmol/day
1st trimester, 0–800 µg/24 hours or 0–2900 nmol/day
3rd trimester, 5,000–50,000 µg/24 hours or 18,000–180,000
nmol/day

Urine Total Estrogens
Men:
Women:

15–40 µg/24 hours or 55–147 nmol/day
Menstruating, 15–80 µg/24 hours or 55–294 nmol/day
Postmenopausal, <20 µg/24 hours or <73 nmol/day
Pregnancy: 1st trimester, 0–800 ug/24 hours or 0–2,900 nmol/day
2nd trimester, 800–5,000 µg/24 hours or 2,900–18,350 nmol/day
3rd trimester, 5,000–50,000 µg/24 hours or 2,900–183,000 nmol/day

Blood Total Estrogens

Men:
20–80 pg/mL or 20–80 ng/L
Women: 60–400 pg/mL or 60–400 ng/L
Postmenopausal: <130 pg/mL or <130 ng/L
Prepuberty: <25 pg/mL or <25 ng/L
Puberty: 30–280 pg/mL or 30–280 ng/mL

NOTE
Total serum estrogen does not measure estriol (E 3) and should not be used in pregnancy or to assess fetal well-being.
Procedure
1. Obtain a venous blood sample if needed for total estrogen.
2. Collect a 24-hour urine specimen and use boric acid preservative for all estrogen tests. Keep the container
refrigerated or on ice during collection.
3. Follow general collection procedures for a 24-hour urine specimen (see Long-Term, Timed Urine Specimen, page
171).
4. Record the age and sex of the patient.
5. Ensure that the number of gestation weeks is communicated if patient is pregnant.
6. Document the number of days into the menstrual cycle for the nonpregnant woman.
Clinical Implications
1. Increased urine E 2 is found in the following conditions:
a. Feminization in children (testicular feminization syndrome)
b. Estrogen-producing tumors
c. Precocious puberty related to adrenal tumors
d. Hepatic cirrhosis
e. Hyperthyroidism
f. In women, estradiol increases during menstruation, before ovulation, and during the 23rd to 41st weeks of
pregnancy.
2. Decreased urine E 2 occurs in:
a. Primary and secondary hypogonadism
b. Kallmann's syndrome
c. Hypofunction or dysfunction of the pituitary or adrenal glands
d. Menopause
3. Increased urine E 3 occurs in pregnancy; there is a sharp rise when delivery is imminent.
4. Decreased urine E 3 is found in:
a. Cases of placental insufficiency or fetal distress (abrupt drop of > 40% on 2 consecutive days). Serial monitoring
of estriol for 4 consecutive days is recommended to evaluate fetal distress.
b. Congenital heart disease
c. Down syndrome
5. Blood and urine total estrogens are increased in:
a. Malignant neoplasm of adrenal gland
b. Malignant neoplasm of cell tumor of ovary
c. Benign neoplasm of ovary
d. Granulosa cell tumor of ovary
e. Lutein cell tumor of ovary
f. Theca cell tumor of ovary
g. Testicular tumors
6. Blood and urine total estrogens are decreased in:
a. Ovarian hypofunction (ovarian agenesis, primary ovarian malfunction)
b. Intrauterine death
c. Preeclampsia
d. Hypopituitarism
e. Hypofunction of adrenal cortex
f. Menopause
g. Anorexia nervosa

Clinical Alert
Estradiol may be used for Pergonal (menotropins, ie, combination of follicle-stimulating and luteinizing hormones used
to promote ovarian follicular growth) monitoring. Serial measurements of E 2 during ovulation induction enable the
physician to minimize high E 2 levels caused by ovarian overstimulation and thereby decrease side effects.

Clinical Alert
Normal values are guidelines and must be interpreted in conjunction with clinical findings.
Interfering Factors
1. Total estrogens
a. Oral contraceptives

b. Estrogen therapy
c. Progesterone therapy
d. Pregnancy and after administration of acetazolamide during pregnancy
2. Estradiol
a. Radioactive pharmaceuticals
b. Oral contraceptives
3. Estriol
a. Glucose and protein interfere with outcome.
b. Day-to-day physiologic variation can be as much as 30%; therefore, single determinations are of limited use.
c. Renal disease—in which case a serum assay would be more accurate.
Interventions
Pretest Patient Preparation
1. Explain the test purpose and procedure.
2. Stress test compliance. The patient must be able to adjust daily activities to accommodate urine collection
protocols.
3. Do not administer radioisotopes for 48 hours before specimen collection.
4. Discontinue all medications for 48 hours before specimen collection (with physician's approval). Drugs deemed
necessary must be documented and communicated.
5. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Resume medications and activity.
2. Interpret test outcomes, monitor, and counsel appropriately.
3. Follow Chapter 1 guidelines for safe, effective, informed posttest care .

URINE DRUG INVESTIGATION SPECIMENS
When screening for unknown drugs, the most valuable samples are obtained from urine, gastric contents, and blood.
Urine drug screening is preferred for several reasons:
1.
2.
3.
4.
5.

Specimens are easily procured.
It is not an invasive procedure (unless bladder catheterization is involved).
Drug concentrations are more elevated in urine or may not be detectable in blood.
Drug metabolites are excreted for a longer period (days or weeks) through urine, indicating past drug use.
Urine test procedures are more easily done and are more economical.

Clinical Alert
Blood is the preferred medium for ethyl alcohol testing because the alcohol concentration is more elevated and
therefore more reliably measured in a blood sample (see Chap. 6).
Toxicology screening should be performed:
1. To confirm clinical or postmortem diagnosis
2. To differentiate drug-induced disease from other causes, such as trauma or metabolic or infectious disease
processes
3. To identify contributing diagnoses, such as ethanol abuse, trauma, presence of other drugs, or underlying
psychosis
4. To seek a basis for high-risk interventions such as hemodialysis
5. To test for drug abuse in the workplace, especially when public safety is at risk or concern; also to test for doping in
athletes
6. As part of preemployment screening for drug use or abuse
7. To test prisoners and parolees randomly to deter or detect drug use ( Chart 3.2)

Chart 3.2 Common Urine Drug Tests *
Alcohol
Amphetamines
Analgesics
Barbiturates
Benzodiazepines
Cocaine, “crack”
Cyanide
Lysergic acid diethylamide (LSD)
Major tranquilizers †
Marijuana
Opiates
Phencyclidine (PCP)
Sedatives
Stimulants
Sympathomimetics
Footnotes
* Many of these drugs are detectable in urine but are not detectable in blood serum. However, all drugs detectable in blood serum are also
detectable in urine, except for glutethimide. † Because minor tranquilizers are almost completely metabolized, they are not likely to be
detected in urine unless an overdose is taken.

Clinical Alert
When reporting drug test results for substance abuse, health care workers and patients need to be aware of the
psychological, social, economic, and legal implications and the potential liabilities associated with mismanaged or
incorrectly reported results. Documented procedures should be established and followed to ensure that before a result
is reported, corroborating evidence exists to support that result. Confirmation of all positive results must be done
through an equally sensitive and specific method that uses a different chemical principle to cross-check the initial
results. Keep in mind that problems associated with incorrect test results are directly proportional to the volume of drug
abuse testing being done.
Urine screening is not a cure-all for preventing substance abuse in the workplace. When properly implemented,
however, it can support a well thought-out substance abuse rehabilitation program. Screening can detect a problem
that the employee may not admit to having. Sure knowledge that an employee abuses drugs allows an employer to
move with confidence toward handling the problem.
Witnessed Urine Sampling for Suspected Substance Abuse
The following procedure is an example of the chain of custody. A chain-of-custody document is originated at the time the
sample is collected. The donor and the individual who witnessed specimen collection must sign and date the document,
as does every person who handles the sample thereafter. The sealed chain-of-custody specimen bag remains in the
possession and control of the collector or is kept in a secured area until shipment to the testing facility. Sealed collections
are placed in large shipping cartons or specially designated bags.
After initial and confirmatory testing, the sample is resealed in a labeled bag and securely stored for 30 days or longer.
All records of tests done on the sample and the chain-of-custody report must be carefully maintained.
The test results should be released only to predesignated, authorized persons to lessen the risk for false or speculative
information being communicated to inappropriate persons.
Several factors may interfere with accurate outcomes and could cause incorrect or false-positive or false-negative
results: higher or lower pH than normal; presence of blood, sodium chloride, detergents, or other contaminants; or low
specific gravity.
Procedure
1. Ensure that the tested patient's signed informed consent form and photo identification are available; they are
required.
2. Instruct patient to remove extra outer garments and leave them outside the bathroom. Make provisions for personal
privacy during specimen procurement.
3. Direct the donor to void a random sample of 60 to 100 mL of urine into the clean specimen cup. The toilet may not
be flushed at any time.
4. Have the witness transfer the contents of the cup into the laboratory specimen bottle on receipt of the voided
specimen from the donor. The donor is present for the entire transfer procedure (viewing this and the following
procedure).
5. Check and record any visible signs of contamination (eg, sediment, discoloration). The entire procedure must be
witnessed by a trained, designated individual who is legally responsible to ensure that the specimen has been
obtained from the correct patient.
6. Affix a temperature-sensing strip to the specimen bottle, and read and record the temperature within 4 minutes of
specimen collection. Temperature strips and collection containers must be at room temperature (urine temperature
must be between 90° and 98°F).
7. Very firmly screw down the cap onto the laboratory specimen bottle to seal it. The rim of the specimen bottle should

8.

9.
10.

11.
12.
13.

be dry.
Affix one end of the tamper-evident tape to the side of specimen bottle. Record the date collected, and have the
donor initial the evidence tape. Wrap the tamper-evident tape across the top of the bottle, and overlap the free end
of the tape with the other end to discourage tampering with the specimen.
Seal the specimen bottle in a zip-lock bag with absorbent material.
After sealing, have the donor sign and date the Drug Screen Request Form in the space provided. The collector
then signs, dates, and provides a telephone number on the Drug Screen Request Form, indicating that all of the
above steps have been followed. Every person who handles the sample thereafter must also sign the form (ie,
chain-of-custody procedure).
Put the original and the first copy of the Drug Screen Form and the sealed laboratory specimen bottle into the
shipping container, and seal it. Place tamper-evident tape across the seal.
Retain the third copy of the form for agency records.
Give the fourth copy of the form to the donor, or send it to the company or place of employment, as required.

Clinical Alert
National Institute for Drug Abuse (NIDA)-approved laboratory standards have stringent requirements. At the collection
site (eg, bathroom), place toilet bluing markers in the toilet tank, and use tamper-proof tape on water faucet and soap
dispensers to prevent water access for specimen dilution.
Clinical Implications Certain drugs can be detected in the urine for hours to several days after ingestion ( Table 3.10).
(Check with agency laboratory for specific drugs and specific time intervals.)
Table 3.10 Screening Limits
Drugs Tested

Screening Cut-off Levels Length of Detection

Alcohol
20 ng/mL
Ethanol (all methods)
Amphetamines
1,000 ng/mL
D-Amphetamine
Methamphetamine
Barbiturates
200 ng/mL
Secobarbital
Benzodiazepines
200 ng/mL
Nordiazepam
Marijuana
50 ng/mL
11-nor-D9-THC-9 COOH
Cocaine metabolite
300 ng/mL
Benzoylecgonine
Methadone
300 ng/mL
Methadone HCl
Methaqualone
300 ng/mL
Methaqualone HCl
Opiates
300 ng/mL
Morphine
PCP
25 ng/mL
Phencyclidine HCl
Propoxyphene
300 ng/mL
D-Propoxyphene HCl
Tricyclic antidepressants (TCAs) 1,000 ng/mL
Desipramine (triage plus TCA)
Heroin
2,000 ng/mL
Acetylmorphine

12 h
2–3 d

Up to 30 d
Up to 40 d
30–60 d
2–4 d
8–60 h
Up to 7 d
2–4 d
2–3 d
1–3 d
1–3 d
1–2 h

Interfering Factors
Factors associated with incorrect test results for urine drug screens include the presence of:
1.
2.
3.
4.
5.
6.

Detergents
Sodium chloride (table salt) (NaCl)
Low SG (dilute urine)
High pH (acid urine)
Low pH (alkaline urine)
Blood in the urine

Interventions
Pretest Patient Preparation
1. Explain the test purpose and the procedure for specimen collection.
2. Follow Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and counsel appropriately regarding results and possible retesting.

2. See Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
Screening tests will be positive for opiates if poppy seeds are ingested (eg, bagels), if the screening cut-off level is 300
ng/mL. Therefore, many screen labs have raised the cut-off level to 2000 ng/mL.

TIMED URINE TESTS
Urine Chloride (Cl), Quantitative (24-Hour)
Normally, the urinary chloride excretion approximates the dietary intake. The amount of chloride excreted in the urine in a
24-hour period is an indication of the state of the electrolyte balance. Chloride is most often associated with sodium
balance and fluid change.
The urine chloride measurement may be used to diagnose dehydration or as a guide in adjusting fluid and electrolyte
balance in postoperative patients. It also serves as a means of monitoring the effects of reduced-salt diets, which are of
great therapeutic importance in patients with cardiovascular disease, hypertension, liver disease, and kidney ailments.
Urine chloride is often ordered along with sodium and potassium as a 24-hour urine test. The urinary anion gap (Na + K)
- Cl is useful for initial evaluation of hyperchloremic metabolic acidosis. It is also used to determine whether a case of
metabolic alkalosis is salt responsive.
Reference Values
Normal
Adult: 140–250 mEq/24 hours or 140–250 mmol/day
Child <6 years old: 15–40 mEq/24 hours or 15–40 mmol/day
Child 10–14 years old: 64–176 mEq/24 hours or 64–176 mmol/day
Children's values are much lower than adult values.
Values vary greatly with salt intake and perspiration.
Different labs may have different values.
It is difficult to talk about normal and abnormal ranges because the test findings have meaning only in relation to salt
intake and output.
Procedure
1. Collect a 24-hour urine specimen.
2. Record the exact starting and ending times on the specimen container and in the patient's health care record.
3. The complete specimen should be sent to the laboratory for refrigeration until it can be analyzed.

Clinical Alert
Because the electrolytes and water balance are so closely related, evaluate the patient's state of hydration by checking
daily weight, by recording accurate intake and output, and by observing and recording skin turgor, the appearance of
the tongue, and the appearance of the urine sample.
Clinical Implications
1. Decreased urine chloride occurs in:
a. Chloride-depleted patients (<10 mEq/L or <10 mmol/L); these patients have low serum chloride and are chloride
responsive (they respond to chloride therapy so that serum and urine levels return to normal).
1. Syndrome of inappropriate antidiuretic hormone (SIADH) secretion
2. Vomiting, diarrhea, excessive sweating
3. Gastric suction
4. Addison's disease
5. Metabolic alkalosis
6. Massive diuresis from any cause
7. Villous tumors of the colon
b. Chloride is decreased by endogenous or exogenous corticosteroids (>20 mEq/L or >20 mmol/L); this condition
is not responsive to chloride administration. Diagnosis of a chloride-resistant metabolic alkalosis helps identify a
corticotropin (ACTH)- or aldosterone-producing neoplasm, such as:
1. Cushing's syndrome
2. Conn's syndrome
3. Mineralocorticoid therapy
4. Postoperative chloride retention
2. Increased urine chloride occurs in:
a. Increased salt intake
b. Adrenocortical insufficiency
c. Potassium depletion
d. Bartter's syndrome
e. Salt-losing nephritis
Interfering Factors
1. Decreased chloride is associated with:

a. Carbenicillin therapy
b. Reduced dietary intake of chloride
c. Ingestion of large amounts of licorice
d. Alkali ingestion
e. Dehydration
2. Increased chloride is associated with:
a. Ammonium chloride administration
b. Excessive infusion of normal saline
c. Ingestion of sulfides, cyanides, halogens, bromides, and sulfhydryl compounds
Interventions
Pretest Patient Preparation
1. Instruct the patient about the test purpose and the method for collecting a 24-hour specimen.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately for fluid imbalances.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .
Urine Sodium (Na), Quantitative (24-Hour)
Sodium is a primary regulator for retaining or excreting water and maintaining acid-base balance. The body has a strong
tendency to maintain a total base content; on a relative scale, only small shifts are found even under pathologic
conditions. As the predominant base substance in the blood, sodium helps to regulate acid-base balance because of its
ability to combine with chloride and bicarbonate. Sodium also promotes the normal balance of electrolytes in the
intracellular and extracellular fluids by acting in conjunction with potassium under the effect of aldosterone. This hormone
promotes the 1:1 exchange of sodium for potassium or the hydrogen ion.
This test measures one aspect of electrolyte balance by determining the amount of sodium excreted in a 24-hour period.
It is done for diagnosis of renal, adrenal, water, and acid-base imbalances.
Reference Values
Normal
Adult: 40–220 mEq/24 hours or 40–220 mmol/day
Child: 41–115 mEq/24 hours or 41–115 mmol/day
Values are diet dependent.
Procedure
1.
2.
3.
4.
5.

Properly label a 24-hour urine container.
The urine container must be refrigerated or kept on ice.
Follow general instructions for 24-hour urine collections (see Long-Term, Timed Urine Specimen, page 171).
Record exact starting and ending times on the specimen container and in the patient's health care record.
Transfer the specimen to the laboratory for proper storage when the test is completed.

Clinical Implications
1. Increased urine sodium occurs in:
a. Adrenal failure (Addison's disease) (primary and secondary)
b. Salt-losing nephritis
c. Renal tubular acidosis
d. SIADH
e. Diabetic acidosis
f. Aldosterone defect (AIDS-related hypoadrenalism)
g. Tubulointerstitial disease
h. Bartter's syndrome
2. Decreased urine sodium occurs in:
a. Excessive sweating, diarrhea
b. Congestive heart failure
c. Adrenocortical hyperfunction
d. Nephrotic syndromes with acute oliguria
e. Prerenal azotemia
f. Cushing's disease
g. Primary aldosteronism
Interfering Factors
1. Increased sodium levels are associated with caffeine intake, diuretic therapy, dehydration, dopamine,
postmenstrual diuresis, increased sodium intake, and vomiting (see Appendix J).
2. Decreased sodium levels are associated with intake of corticosteroids and propranolol; low sodium intake;
premenstrual and water retention; overhydration and stress diuresis (see Appendix J).
Interventions
Pretest Patient Preparation

1. Instruct the patient about the purpose of the test, method of collection, and specimen refrigeration or icing. Written
instructions can be helpful.
2. Encourage intake of food and fluids.
3. Follow Chapter 1 guidelines for safe, effective, informed pretest care.

Clinical Alert
Because electrolytes and water balance are so closely related, determine the patient's state of hydration by checking
and recording daily weights, accurate intake and output of fluids, and observations about skin turgor, the appearance
of the tongue, and the appearance of the urine.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor as necessary for fluid and electrolyte state.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Urine Potassium (K), Quantitative (24-Hour) and Random
Potassium acts as a part of the body's buffer system and serves a vital function in the body's overall electrolyte balance.
Because the kidneys cannot completely conserve potassium, this balance is regulated by the excretion of potassium
through the urine. It takes the kidney 1 to 3 weeks to conserve potassium effectively.
This test provides insight into electrolyte balance by measuring the amount of potassium excreted in 24 hours. This
measurement is useful in the study of renal and adrenal disorders and water and acid-base imbalances. An evaluation of
urinary potassium can be helpful in determining the origin of abnormal potassium levels. Urine potassium values <20
mEq/L (or <20 mmol/L) are associated with nonrenal conditions, whereas values >20 mEq/L (or >20 mmol/L) are
associated with renal causes.
Reference Values
Normal
Adult: 25–125 mEq/24 hours or 25–125 mmol/day
Child: 10–60 mEq/24 hours or 10–60 mmol/day
Values are diet dependent.
Procedure
1.
2.
3.
4.
5.
6.

Label a 24-hour urine container properly.
Refrigerate the urine container or keep it on ice during the collection.
Follow general instructions for 24-hour urine collection (see Long-Term, Timed Urine Specimen, page 171).
Record exact starting and ending times on the container and in the patient's health care record.
Transfer the specimen to the laboratory for proper storage.
A random urine potassium determination may be done.

Clinical Implications
1. Increased urine potassium occurs in:
a. Primary renal diseases
b. Diabetic and renal tubule acidosis
c. Albright-type renal disease
d. Starvation (onset)
e. Primary and secondary aldosteronism
f. Cushing's syndrome
g. Onset of metabolic alkalosis
h. Fanconi's syndrome
i. Bartter's syndrome
2. Decreased urine potassium occurs in:
a. Addison's disease
b. Severe renal disease (eg, pyelonephritis, glomerulonephritis)
c. In patients with potassium deficiency, regardless of the cause, the urine pH tends to fall.
This occurs because hydrogen ions are released in exchange for sodium ions, given that both potassium and hydrogen
are excreted by the same mechanism.
Interfering Factors
1. Increased urinary potassium is associated with:
a. Acetazolamide and other diuretics
b. Cortisone
c. Ethylenediaminetetraacetic acid (EDTA) anticoagulant
d. Penicillin, carbenicillin
e. Thiazides
f. Licorice
g. Sulfates (see Appendix J)
2. Decreased urinary potassium is associated with:
a. Amiloride
b. Diazoxide

c. Intravenous glucose infusion (see Appendix J)

Clinical Alert
In the presence of excessive vomiting or gastric suctioning, the resulting alkalosis maintains urinary potassium
excretion at levels inappropriately high for the degree of actual potassium depletion that occurs.
Interventions
Pretest Patient Preparation
1. Instruct the patient about the purpose of the test, the collection procedure, and the need for refrigeration or icing of
the 24-hour urine specimen. Written instructions can be helpful.
2. Food and fluids are permitted and encouraged.
3. Follow Chapter 1 guidelines for safe, effective, informed pretest care.

Clinical Alert
1. Because electrolytes and water balance are so closely related, determine the patient's state of hydration by
checking and recording daily weights, accurate intake and output of fluids, and observations about skin turgor,
the appearance of the tongue, and the appearance of the urine.
2. Observe for signs of muscle weakness, tremors, changes in electrocardiographic tracings, and dysrhythmias. The
degree of hypokalemia or hyperkalemia at which these symptoms occur varies with each person.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately for signs and symptoms of electrolyte imbalances and kidney
disorders.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .
Urine Uric Acid, Quantitative (24-Hour)
Uric acid is formed from the metabolic breakdown of nucleic acids composed of purines. Excessive uric acid relates to
excessive dietary intake of purines or to endogenous uric acid production in certain disorders. Normally, one third of the
uric acid formed is degraded by bacteria in the intestines.
This test evaluates uric acid metabolism in gout and renal calculus formation. Evaluation of excess uric acid excretion is
important to aid in evaluating stone formation and nephrolithiasis. It also reflects the effects of treatment with uricosuric
agents by measuring the total amount of uric acid excreted within a 24-hour period.
Reference Values
Normal
With normal diet: 250–750 mg/24 hours or 1.48–4.43 mmol/day
With purine-free diet: <400 mg/24 hours or <2.48 mmol/day
With high-purine diet: <1000 mg/24 hours or <5.90 mmol/day
Procedure
1.
2.
3.
4.

Properly label a 24-hour urine container to which the appropriate preservative has been added.
Follow general instructions for 24-hour urine collection (see Long Term, Timed Urine Specimen, page 171).
Record exact starting and ending times on the specimen container and in the patient's health care record.
When collection is completed, send the specimen to the laboratory.

Clinical Implications
1. Increased urine uric acid (uricosuria) occurs in:
a. Nephrolithiasis (primary gout)
b. Chronic myelogenous leukemia (secondary nephrolithiasis)
c. Polycythemia vera
d. Lesch-Nyhan syndrome
e. Wilson's disease
f. Viral hepatitis
g. Sickle cell anemia
h. High uric acid concentration in urine with low urine pH may produce uric acid stones in the urinary tract. (These
patients do not have gout.)
2. Decreased urine uric acid is found in:
a. Chronic kidney disease
b. Xanthinuria
c. Folic acid deficiency
d. Lead toxicity
Interfering Factors
1. Many drugs increase uric acid levels, including:
a. Salicylates (aspirin) and other anti-inflammatory drugs
b. Diuretics
c. Vitamin C (ascorbic acid)

d. Warfarin
e. Cytotoxic drugs used to treat lymphoma and leukemia (see Appendix J)
2. Other factors increasing uric acid urine levels include:
a. X-ray contrast media
b. Strenuous exercise
c. Diet high in purines (eg, kidney, sweetbreads) (see Chap. 6)
3. Allopurinol decreases uric acid levels (see Appendix J)
Interventions
Pretest Patient Preparation
1. Instruct the patient about the test purpose, interfering factors, collection process, and refrigeration or icing of the
24-hour urine specimen. A written reminder may be helpful.
2. Encourage food and fluids. In some situations, a diet high or low in purines may be ordered during and before
specimen collection.
3. Follow Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Resume usual diet.
2. Interpret test outcomes and counsel appropriately regarding prescribed treatment and possible need for further
testing.
3. See Chapter 1 guidelines for safe, effective, informed posttest care .
Urine Calcium (Ca), Quantitative (24-Hour)
Calcium hemostasis is maintained by the parathyroid hormone. The bulk of calcium excreted is eliminated in the stool.
However, a small quantity of calcium is normally excreted in the urine. This amount varies with the quantity of dietary
calcium ingested. Increased calcium in urine results from an increase in intestinal calcium absorption, a lack of renal
tubule reabsorption of calcium, resorption or loss of calcium from bone, or a combination of these mechanisms. Values in
both healthy and sick persons have a wide range.
The urine calcium test is used for evaluation of calcium intake and/or the rate of intestinal absorption, bone resorption,
and renal loss. Urine calcium is high in 30% to 80% of cases of primary hyperparathyroidism but does not reliably
diagnose this disease. Urine calcium test does not have much value in a differential diagnosis.
Reference Values
Normal
Normal diet: 100–300 mg/24 hours or 2.50–7.50 mmol/day
Low-calcium diet: 50–150 mg/24 hours or 1.25–3.75 mmol/day
Procedure
1. Label properly a 24-hour urine container.
2. Procure an acid-washed bottle. See Table 3-3 regarding 24-hour urine collection data.
3. Follow general instructions for 24-hour urine collection (see Long-Term, Timed Urine Specimen, page 171).
Refrigerate during collection.
4. Record exact starting and ending times of the collection on the specimen container and in the patient's health care
record.
5. Send the specimen to the laboratory when collection is completed.
6. Perform a random (Sulkowitch) test in an emergency. Follow directions for random urine collection in first part of the
chapter.
Clinical Implications
1. Increased urine calcium is found in:
a. Hyperparathyroidism (30% to 80% of cases)
b. Sarcoidosis
c. Primary cancers of breast and bladder
d. Osteolytic bone metastases (carcinoma, sarcoma)
e. Multiple myeloma
f. Paget's disease
g. Renal tubular acidosis
h. Fanconi's syndrome
i. Vitamin D intoxication
j. Idiopathic hypercalcuria
k. Osteoporosis (especially after immobilization)
l. Osteitis deforms
m. Thyrotoxicosis
2. Increased urinary calcium almost always accompanies increased blood calcium levels.
3. Calcium excretion levels greater than calcium intake levels are always excessive; urine excretion values > 400–500
mg/24 hours (>10–12.5 mmol/d) are reliably abnormal.
4. Increased calcium excretion occurs whenever calcium is mobilized from the bone, as in metastatic cancer or
prolonged skeletal immobilization.
5. When calcium is excreted in increasing amounts, the situation creates the potential for nephrolithiasis or
nephrocalcinosis, especially with high protein intake.

6. Decreased urine calcium is found in:
a. Hypoparathyroidism
b. Familial hypocalcuria hypercalcemia
c. Vitamin D deficiency
d. Preeclampsia
e. Acute nephrosis, nephritis, renal failure
f. Renal osteodystrophy
g. Vitamin D–resistant rickets
h. Metastatic carcinoma of prostate
i. Malabsorption syndrome—celiac-spruce disease, steatorrhea
7. Urine calcium decreases late in normal pregnancy.
Interfering Factors
1. Falsely elevated levels may be caused by:
a. Some drugs (eg, calcitonin; vitamins A, K, and C; and corticosteroids) (see Appendix J)
b. Urine procured immediately after meals in which high calcium intake has occurred (eg, milk)
c. Increased exposure to sunlight
d. Immobilization (especially in children)
2. Falsely decreased levels may be found with:
a. Increased ingestion of phosphate, bicarbonate, antacids
b. Alkaline urine
c. Thiazide diuretics (can be used to lower calcium levels therapeutically)
d. Oral contraceptives, estrogens
e. Lithium (see Appendix J)
Interventions
Pretest Patient Preparation
1. Instruct the patient about the test purpose and procedure. Written instructions may be helpful.
2. Encourage food and fluids.
3. If the urine calcium test is done because of a metabolic disorder, the patient should eat a low-calcium diet, and
calcium medications should be restricted for 1 to 3 days before specimen collection.
4. For a patient with a history of renal stone formation, urinary calcium results will be more meaningful if the patient's
usual diet is followed for 3 days before specimen collection. Do not stop medications.
5. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes, monitor and counsel accordingly regarding calcium imbalances.
2. Follow Chapter 1 guidelines regarding safe, effective, informed posttest care.

Clinical Alert
1. Observe patients with very low urine calcium levels for signs and symptoms of tetany (muscle spasms, twitching,
hyperirritable nervous system).
2. The first sign of calcium imbalance may be pathologic fracture that can be related to calcium excess.
3. The Sulkowitch test (random urine sample) can be used in an emergency, especially when hypercalcemia is
suspected, because hypercalcemia is life-threatening.
Urine Magnesium (Mg), Quantitative (24-Hour)
Magnesium excretion controls serum magnesium balance. Urinary magnesium excretion is diet dependent. With normal
dietary intake of 200–500 mg/day, urine excretion is normally 75–150 mg/24 hours (3–6 mmol/d). The remainder of the
dietary intake is excreted in the stool.
This test evaluates magnesium metabolism, investigates electrolyte status, and is a component of a workup for
nephrolithiasis. It is useful for assessing the cause of abnormal serum magnesium.
Reference Values
Normal
75–150 mg/24 hours or 3.0–6.0 mEq/24 hours or 3.00–6.00 mmol/day
Procedure
1. Collect a 24-hour urine specimen in a metal-free and acid-rinsed container. The pH must be < 2.
2. Record exact starting and ending times.
3. See Long-Term, Timed Urine Specimen (page 171) for 24-hour urine collection guidelines.
Clinical Implications
1. Increased urine magnesium is associated with:
a. Increased blood alcohol
b. Bartter's syndrome
c. Chronic glomerulonephritis

2. Decreased urine magnesium is associated with:
a. Malabsorption
b. Long-term chronic alcoholism (poor diet)
c. Long-term parenteral therapy
d. Magnesium deficiency
e. Chronic renal disease
f. Hypoparathyroidism
g. Hypercalcuria
h. Decreased renal function (eg, Addison's disease)
Interfering Factors
1. Increased magnesium levels are associated with:
a. Corticosteroids
b. Cisplatin therapy
c. Thiazide diuretics
d. Amphotericin (see Appendix J)
e. Blood in urine
2. Decreased magnesium levels; many drugs affect test outcomes (see Appendix J)
Interventions
Pretest Patient Preparation
1. Explain purpose of test and collection procedures.
2. Instruct that the specimen will be unacceptable if it comes in contact with any type of metal.
3. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately for abnormal magnesium excretion.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Urine Oxalate, Quantitative (24-Hour)
Oxalate is an end product of metabolism. Normal oxalate is derived from dietary oxalic acid (10%) and from the
metabolism of ascorbic acid (35%–50%) and glycine (40%). Patients who form calcium oxalate kidney stones appear to
absorb and excrete a higher proportion of dietary oxalate in the urine.
The 24-hour urine collection for oxalate is indicated in patients with surgical loss of distal small intestine, especially those
with Crohn's disease. The incidence of nephrolithiasis in patients who have inflammatory bowel disease is 2.6% to 10%.
Hyperoxaluria is regularly present after jejunoileal bypass for morbid obesity; such patients may develop nephrolithiasis.
Oxaluria is also a characteristic of ethylene glycol intoxication. Additionally, vitamin C increases oxalate excretion and in
some people may be a risk factor for calcium oxalate nephrolithiasis. Such ingestion can usually be determined through
the patient's history. If oxalate excretion becomes normal after reduction of vitamin C intake, additional therapy to prevent
stones may not be required.
Reference Values
Normal
Men: <55 mg/24 hours or <611 µmol/day
Women: <50 mg/24 hours or <555 µmol/day
Procedure
1. Collect and refrigerate or place on ice a 24-hour urine specimen according to protocols. Do not acidify.
2. See Long-Term, Timed Urine Specimen (page 171) for directions for a 24-hour urine collection.
Clinical Implications
1. Increased urine oxalate is associated with:
a. Ethylene glycol poisoning (>150 mg/24 hours or >1700 µmol/day)
b. Primary hyperoxaluria, a rare genetic disorder (100–600 mg/24 hours or 1100–6700 µmol/ day
[nephrocalcinosis])
c. Pancreatic disorders (diabetes, steatorrhea)
d. Cirrhosis, biliary diversion
e. Vitamin B 6 deficiency (pyridoxine)
f. Sarcoidosis
g. Crohn's disease (inflammatory bowel disease)
h. Celiac disease (sprue)
i. Jejunoileal bypass for treatment of morbid obesity
2. Decreased urine oxalate occurs in renal failure
Interfering Factors
1. Foods containing oxalates, such as rhubarb, strawberries, beans, beets, spinach, tomatoes, gelatin, chocolate,

cocoa, and tea, cause increased levels.
2. Ethylene glycol and methoxyflurane cause increased levels (see Appendix J).
3. Calcium causes decreased levels (see Appendix J).
4. Ascorbic acid (vitamin C) increases levels.
Interventions
Pretest Patient Preparation
1. Explain test purpose and procedure.
2. Advise the patient to avoid foods that promote oxalate excretion before the test. A list of such foods is helpful.
Normal fluid intake should be continued.
3. Vitamin C should not be taken within 24 hours before the beginning of the test nor during the test.
4. The patient should be ambulatory and preferably at home.
5. Follow Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Resume normal diet and exercise.
2. Interpret test outcomes and counsel appropriately about abnormal levels.
3. See Chapter 1 guidelines for safe, effective, informed posttest care .
Urine Pregnanediol (24-Hour)
Pregnanediol levels in normally menstruating women are constant during the follicular phase. Levels increase sharply
during the luteal phase. During pregnancy, levels gradually increase, falling sharply before the onset of labor and
delivery.
This test measures ovarian and placental function. Specifically, it measures a part of the hormone progesterone and its
principal excreted metabolite, pregnanediol. Progesterone exerts its main effect on the endometrium by causing the
endometrium to enter the secretory phase and to become ready for the implantation of the blastocyte should fertilization
take place.
Pregnanediol excretion is elevated in pregnancy and decreased in luteal deficiency or placental failure.

NOTE
A serum progesterone test is more informational and is now used as an index of progesterone production.
Reference Values
Normal
This test is difficult to standardize; it varies with age, sex, and length of existing pregnancy.
Child:
Men:
Women:

<0.1 mg/24 hours or <0.312 µmol/day
0–1.9 mg/24 hours or 0–5.9 µmol/day
Follicular phase, 0–2.6 mg/24 hours or 0–8.1 µmol/day
Luteal, 2.6–10.6 mg/24 hours or 8.1–33.1 µmol/day
Pregnancy: 1st trimester, 10–35 mg/24 hours or 31–109 µmol/day
2nd trimester, 35–70 mg/24 hours or 109–218 µmol/day
3rd trimester, 70–100 mg/24 hours or 218–312 µmol/day

Procedure
1.
2.
3.
4.
5.

Label a 24-hour urine container properly.
Refrigerate the specimen or use a boric acid preservative. Check laboratory policy. Protect the specimen from light.
Follow general instructions for 24-hour urine collection (see Long-Term, Timed Urine Specimen, page 171).
Record exact starting and ending times on the specimen container and in the patient's health care record.
Send the completed specimen to the laboratory.

Clinical Implications
1. Increased urine pregnanediol is associated with:
a. Luteal cysts of ovary (ovarian cyst)
b. Arrhenoblastoma of the ovary
c. Congenital hyperplasia of adrenal gland
d. Granulosa theca cell tumor of ovary
2. Decreased urine pregnanediol is associated with:
a. Amenorrhea (ovarian hypofunction)
b. Threatened abortion (if <5.0 mg/24 hours or <15.6 µmol/day, abortion is imminent)
c. Fetal death, intrauterine death, placental insufficiency
d. Toxemia, eclampsia
e. Ovarian failure
f. Chronic nephritis in pregnancy

Interfering Factors
Decreased values occur with estrogen or progesterone therapy and with the usage of oral contraceptives.
Interventions
Pretest Patient Preparation
1. Instruct the patient about the test purpose and the 24-hour urine specimen collection procedure. A written reminder
may be helpful.
2. Allow food and fluids.
3. See Chapter 1 guidelines regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and counsel appropriately about abnormal ovarian and placental function.
2. Follow Chapter 1 guidelines regarding safe, effective, informed posttest care.
Urine Pregnanetriol (24-Hour)
Pregnanetriol is a ketogenic steroid reflecting one segment of adrenocorticol activity. Pregnanetriol should not be
confused with pregnanediol, despite the similarity of name. This test has been largely replaced with the serum test
17-hydroxyprogesterone.
This 24-hour urine test is done to diagnose congenital adrenal hyperplasia, adrenogenital syndrome, owing to a defect in
21-hydroxylation. The diagnosis of adrenogenital syndrome is indicated in:
1.
2.
3.
4.
5.

Adult women who show signs and symptoms of excessive androgen production with or without hypertension.
Craving for salt
Sexual precocity in boys
Infants who exhibit signs of failure to thrive
Presence of external genitalia in females (pseudohermaphroditism). In males, differentiation must be made between
a virilizing tumor of the adrenal gland, neurogenic and constitutional types of sexual precocity, and interstitial cell
tumor of the testes.

Reference Values
Normal
Adult female: 0–1.4 mg/24 hours or 0–4.2 µmol/day
Adult male: 0.2–2.2 mg/24 hours or 0.6–6.5 µmol/day
Child (<9 years old): <0.3 mg/24 hours or <0.9 µmol/day
Child (10–16 years old): 0.1–0.6 mg/24 hours or 0.3–1.8 µmol/day
Procedure
1. Label a 24-hour urine container properly.
2. Refrigerate the specimen if necessary; some laboratories may require a boric acid preservative in the collection
receptacle.
3. Follow general instructions for 24-hour urine collection (see Long-Term, Timed Urine Specimen, page 171).
4. Record exact starting and ending times on the specimen container and in the patient's health care record.
5. Send the completed specimen to the laboratory.
Clinical Implications
1. Elevated urine pregnanetriol occurs in:
a. Congenital adrenocortical hyperplasia
b. Stein-Leventhal syndrome
c. Ovarian and adrenal tumors
2. Decreased urine pregnanetriol occurs in:
a. Hydroxylase deficiency (rare)
b. Ovarian failure
Interventions
Pretest Patient Preparation
1. Instruct the patient about the test purpose and procedure for collection of a 24-hour urine specimen. A written
reminder may be helpful.
2. Allow food and fluids.
3. Avoid muscular exercise before and during specimen collection.
4. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and counsel appropriately about adrenogenital syndrome.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Urine 5-Hydroxyindoleacetic Acid (5-HIAA) (24-Hour)
Serotonin is a vasoconstricting hormone normally produced by the argentaffin cells of the gastrointestinal tract. The

principal function of the cells is to regulate smooth muscle contraction and peristalsis. 5-hydroxyindoleacetic acid
(5-HIAA) is the major urinary metabolite of serotonin. 5-HIAA assays are more useful than the parent hormone serotonin.
This urine test is conducted to diagnose the presence of a functioning carcinoid tumor, which can be shown by significant
elevations of 5-HIAA. Excess amounts of 5-HIAA are produced by most carcinoid tumors. Carcinoid tumors produce
symptoms of flushing, hepatomegaly, diarrhea, bronchospasm, and heart disease.
Reference Values
Normal
Qualitative: Negative
Quantitative: 2–7 mg/24 hours or 11–37 µmol/day
Procedure
1. Do not allow the patient to eat any bananas, pineapple, tomatoes, eggplants, plums, or avocados for 48 hours
before or during the 24-hour test because these foods contain serotonin.
2. Properly label a 24-hour urine container that contains the preservative (acid).
3. Discontinue the following drugs 48 hours before sample collection: acetaminophen, salicylates, phenacetin,
naproxen, imipramine, and monoamine oxidase inhibitors.
4. Follow general directions for 24-hour urine collection (see Long-Term, Timed Urine Specimen, page 171).
5. Record exact starting and ending times of the collection on the specimen container and in the patient's health care
record.
6. Send the completed specimen to the laboratory.
Clinical Implications
1. Levels > 25 mg/24 hours or > 131 µmol/day indicate large carcinoid tumors, especially when metastatic:
a. Ileal tumors
b. Pancreatic tumors
c. Duodenal tumors
d. Biliary tumors
2. Increased urine 5-HIAA is found in:
a. Ovarian carcinoid tumor
b. Nontropical sprue
c. Bronchial adenoma (carcinoid type)
d. Malabsorption
e. Celiac disease
f. Whipple's disease
g. Oat cell cancer of respiratory system
3. Decreased urine 5-HIAA is found in:
a. Depressive illness
b. Small intestine resection
c. Phenylketonuria (PKU)
d. Hartnup's disease
e. Mastocytosis
Interfering Factors
1. False-positive results occur with:
a. Ingestion of banana, pineapple, plum, walnut, eggplant, tomato, chocolate, and avocado, because of their
serotonin content
b. Many drugs (see Appendix J)
c. After surgery (surgical stress)
2. False-negative results can be caused by specific drugs that depress 5-HIAA production.
Interventions
Pretest Patient Preparation
1. Instruct the patient about test purpose and procedure for collection of the 24-hour urine specimen. Written
instructions may be helpful.
2. Encourage intake of food and water. Foods high in serotonin content must not be eaten for 48 hours before or
during the test.
3. If possible, no drugs should be taken for 72 hours before the test nor during the test (especially aforementioned
drugs), including over-the-counter drugs.
4. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Resume normal diet and medications when test is completed.
2. Interpret test outcome and counsel appropriately about abnormal 5-HIAA levels.
3. Follow Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
A serum serotonin assay may detect some carcinoids missed by the urine 5-HIAA assay.

Urine Vanillylmandelic Acid (VMA); Catecholamines (24-Hour)
The principal substances formed by the adrenal medulla and excreted in urine are VMA, epinephrine, norepinephrine,
metanephrine, and normetanephrine. These substances contain a catechol nucleus together with an amine group and
therefore are referred to as catecholamines. Most of these hormones are changed into metabolites, the principal one
being 3-methoxy-4-hydroxymandelic acid, known as vanillylmandelic acid, or VMA.
VMA is the primary urinary metabolite of the catecholamine group. It has a urine concentration 10 to 100 times greater
than the concentrations of the other amines. It is also fairly simple to detect; methods used for catecholamine
determination are much more complex.
This 24-hour urine test of adrenomedullary function is done primarily when pheochromocytoma, a tumor of the chromaffin
cells of the adrenal medulla, is suspected in a patient with hypertension.
The assay for pheochromocytoma is most valuable when a urine specimen is collected during a hypertensive episode.
Because a 24-hour urine collection represents a longer sampling time than a symptom-directed serum sample, the
24-hour urine test may detect a pheochromocytoma missed by a single blood level determination.
Reference Values
Normal
Adults
VMA: up to 9 mg/24 hours or up to 45 µmol/day
Catecholamines (total): <100 µg/day or <591 nmol/day
Epinephrine: 0–20 µg/24 hours or 0–109 nmol/day
Metanephrine: 74–297 µg/24 hours or 375–1506 nmol/day
Norepinephrine: 15–80 µg/24 hours or 89–473 nmol/day
Normetanephrine: 105–354 µg/24 hours or 573–1933 nmol/day
Dopamine: 65–400 µg/24 hours or 420–2612 nmol/day
Children's levels are different from those of adults. Check with your laboratory for values in children.

NOTE
Different laboratories report values in different units—this should be kept in mind when analyzing results.
Procedure
1. Properly label a 24-hour container with acid preservative and refrigerate the container or keep it on ice.
2. Follow general instructions for 24-hour urine collection (see Long-Term, Timed Urine Specimen, page 171).
3. Record exact starting and ending times of the collection on the specimen container and in the patient's health care
record.
4. Send the specimen to the laboratory.
Clinical Implications
1. Increased urine VMA occurs as follows:
a. High levels in pheochromocytoma
b. Slight to moderate elevations in
1. Neuroblastoma
2. Ganglioneuroma
3. Ganglioblastoma
4. Carcinoid tumor (some cases)
2. Increased urine catecholamines are found in:
a. Pheochromocytoma
1. Norepinephrine, >170 mg/24 hours or >170 mg/day
2. Epinephrine, >35 mg/24 hours or >35 mg/day
b. Neuroblastomas
c. Ganglioneuromas
d. Myocardial infarction (acute)
e. Hypothyroidism
f. Diabetic acidosis
g. Long-term manic-depressive states
3. Decreased urine catecholamines are found in:
a. Diabetic neuropathy
b. Parkinson's disease
Interfering Factors
1. Increased urine VMA and catecholamines are caused by:
a. Hypoglycemia—for this reason, the test should not be scheduled while the patient is receiving nothing by mouth.
b. Many foods, such as the following:
1. Caffeine-containing products (eg, tea, coffee, cocoa, carbonated drinks)
2. Vanilla
3. Fruit, especially bananas
4. Licorice
c. Many drugs cause increased VMA levels, especially reserpine, a-methyldopa, levodopa, monoamine oxidase

inhibitors, sinus and cough medicines, bronchodilators, and appetite suppressants.
d. Exercise, stress, smoking, and pain cause physiologic increases of catecholamines.
e. Heavy alcohol intake increases catecholamine levels.
2. Falsely decreased levels of VMA and catecholamines are caused by:
a. Alkaline urine
b. Uremia (causes toxicity and impaired excretion of VMA)
c. Radiographic contrast agents—for this reason, an intravenous pyelogram should not be scheduled before a
VMA test.
d. Certain drugs (see Appendix J)
Interventions
Pretest Patient Preparation
1. Instruct the patient about the test purpose and the procedure for collection of the 24-hour urine specimen. A written
reminder may be helpful, especially regarding restricted foods.
2. Explain diet and drug restrictions. Diet restrictions vary among laboratories, but coffee, tea, bananas, cocoa
products, vanilla products, and aspirin are always excluded for 3 days (2 days before and 1 day during specimen
collection).
3. Many laboratories require that all drugs be discontinued for 1 week before testing.
4. Encourage adequate rest, food, and fluids.
5. Stress, strenuous exercise, and smoking should be avoided during the test.
6. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. The patient may resume pretest diet, drugs, and activity when the test is completed.
2. Interpret test outcomes and counsel appropriately.
3. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Urine Porphyrins and Porphobilinogens (24-Hour and Random); ?-Aminolevulinic Acid (ALA, ?-ALA)
Porphyrins are cyclic compounds formed from ?-aminolevulinic acid (?-ALA), which plays a role in the formation of
hemoglobin and other hemoproteins that function as carriers of oxygen in the blood and tissues. In health, insignificant
amounts of porphyrin are excreted in the urine. However, in certain conditions, such as porphyria (disturbance in
metabolism of porphyrin), liver disease, and lead poisoning, increased levels of porphyrins and ?-ALA are found in the
urine. Disorders in porphyrin metabolism also result in increased amounts of porphobilinogen in urine. The most common
signs and symptoms of acute intermittent porphyria are abdominal pain, photosensitivity, sensory neuropathy, or
psychosis. Patients with the porphyrias may pass urine that is pink, port wine, or burgundy colored.
When urine is tested for the presence of porphyrins, porphobilinogen, and/or ALA, it is also given the black-light
screening test (Wood's light test). Porphyrins are fluorescent when exposed to black or ultraviolet light. See Chapter 2 for
other tests for porphyria.
This test is used to diagnose porphyrias and lead poisoning in children. The following is a summary of laboratory findings
for various porphyrias.
Congenital Erythropoietic Porphyria. Elevations of urine uroporphyrin and coproporphyrin occur, with the former
exceeding the latter. Lesser amounts of hepta, hexa, and penta carboxyporphyrins are secreted. ALA and
porphobilinogen levels are normal.
Acute Intermittent Porphyria. Porphobilinogen and ?-ALA are elevated in acute attacks, and small increases of urine
uroporphyrin and coproporphyrin may be found. During periods of latency, the values are normal.
Porphyria Cutanea Tarda. A more common form of porphyria—increased uroporphyrins, uroporphyrinogen, and hepta
carboxylporphyrins.
Protoporphyria. Mild disease, which mainly has the clinical symptoms of solar urticaria and solar eczema (exposure to
sunshine). Increased fecal protoporphyrin.
Hereditary Coproporphyria. Urine coproporphyrin and porphobilinogen are markedly increased during acute attacks;
increases of urine uroporphyrin may also be found.
Variegate Porphyria. In acute attacks, results are similar to those seen in acute intermittent porphyria. Porphobilinogen
and ?-ALA usually return to normal between attacks. Urine coproporphyrin exceeds uroporphyrin excretion during acute
attacks.
Chemical Porphyrias. (“Intoxication porphyria.”) Porphyrinogenic chemicals include certain halogenated hydrocarbons,
which cause increased uroporphyrin levels in the urine. Also increased are ALA, coproporphyrin, and porphobilinogen.
Lead Poisoning. ?-ALA levels exceed those of porphobilinogen, which may remain normal. In children, ALA secretion in
urine is more sensitive than blood lead levels.
Reference Values
Normal

Porphobilinogens
Random specimen: 0–2.0 mg/L or negative or 0–8.8 µmol/L
24-hour specimen: 0–1.5 mg/24 hours or 0–6.6 mg/day
?- ALA Random specimen: 0–4.5 mg/L or 0–34 µmol/L
24-hour specimen: 1.5–7.5 mg/24 hours or 11.4–57.2 µmol/day ( Table 3.11)
Table 3.11 Specimen Values
Male
Porphyrins *
Random specimen
24-h Specimens:
Uroporphyrin
Coproporphyrin
Heptacarboxyporphyrin
Pentacarboxyporphyrin
Hexacarboxyporphyrin
*Total porphyrins: 20–121 µg/L or 24–146 nmol/L.

Female

(µg/24 h) (nmol/d) (µg/24 h) (nmol/d)
Negative
8–44
10–109
0–12
0–4
0–5

10–53
15–167
0–15
0–6
0–7

Negative
4–22
3–56
0–9
0–3
0–5

10–26
5–86
0–11
0–4
0–5

Procedure
1. Properly label a 24-hour clean-catch urine container.
2. Provide refrigeration or icing. The specimen must be kept protected from exposure to light. Check with your
laboratory regarding the need for preservatives.
3. Follow general instructions for 24-hour urine collection (see Long-Term, Timed Urine Specimen, page 171).
4. Record exact starting and ending times on the specimen container and in the patient's health care record.
5. Send the specimen to the laboratory.
6. Obtain midmorning or midafternoon specimens for random tests because it is more likely that the patient will
excrete porphyrins at those times. Transport the specimen to the laboratory immediately. Protect the specimen from
light.
7. Observe and record the urine color. If porphyrins are present, the urine may appear amber-red or burgundy in
color, or it may vary from pale pink to almost black. Some patients excrete urine of normal color that turns dark after
standing in the light.
Clinical Implications
1. Increased urine porphobilinogen occurs in:
a. Porphyria (acute intermittent type)
b. Variegate porphyria
c. Hereditary coproporphyria
d. See pages 246–247 for list of other porphyrias.
2. Increased fractionated porphyrins occur in:
a. Acute intermittent porphyria
b. Congenital erythropoietic porphyria
c. Hereditary porphyria
d. Variegate porphyria
e. Chemical porphyria caused by heavy-metal poisoning or carbon tetrachloride
f. Lead poisoning
g. Viral hepatitis
h. Cirrhosis (alcoholism)
i. Newborn of mother with porphyria
j. Congenital hepatic porphyria
3. Increased urine ?- ALA can occur in:
a. Acute intermittent porphyria (acute phase)
b. Variegate porphyria (during crisis)
c. Hereditary coproporphyria
d. Lead poisoning does not increase urine ?-ALA until serum lead levels reach > 40 µg/dL; urine ?-ALA may
remain elevated for several months after control of lead exposure.
e. Congenital hepatic porphyria
f. Slight increase in pregnancy, diabetic acidosis
4. Decreased urine ?- ALA is found in alcoholic liver disease

Clinical Alert
Porphobilinogen is not increased in lead poisoning.
Interfering Factors
1. Oral contraceptives and diazepam can cause acute porphyria attacks in susceptible patients.
2. Alcohol ingestion interferes with the test.
3. Many other drugs, especially phenazopyridine, procaine, sulfamethoxazole, and the tetracyclines, interfere with the

test (see Appendix J).
Interventions
Pretest Patient Preparation
1. Instruct the patient about the purpose and procedure of collection a 24-hour urine specimen. A written reminder
may be helpful.
2. Allow food and fluids, but alcohol and excessive fluid intake should be avoided during the 24-hour collection.
3. If possible, discontinue all drugs for 2 to 4 weeks before the test so that results will be accurate.
4. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. The patient may resume normal activities and medications.
2. Interpret test outcomes and counsel appropriately.
3. Follow Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
This test should not be ordered for patients receiving Donnatal or other barbiturate preparations. However, if
intermittent porphyria is suspected, the patient should take those medications according to prescribed protocols
because these drugs may provoke an attack of porphyria.
Urine Amylase Excretion and Clearance (Random, Timed Urine, and Blood)
Amylase is an enzyme that changes starch to sugar. It is produced in the salivary glands, pancreas, liver, and fallopian
tubes and is normally excreted in small amounts in the urine. If the pancreas or salivary glands are inflamed, much more
of the enzyme enters the blood and, consequently, more amylase is excreted in the urine.
This test of blood and urine indicates pancreatic function and is done to differentiate acute pancreatitis from other causes
of abdominal pain, epigastric discomfort, or nausea and vomiting.
In patients with acute pancreatitis, the urine often shows a prolonged elevation of amylase, compared with a short-lived
peak in the blood. Moreover, urine amylase may be elevated when blood amylase is within normal range, and,
conversely, the blood amylase may be elevated when the urine amylase is within normal range. The advantage of the
amylase-creatinine clearance test is that it can be done on a single random urine specimen and a single serum sample
instead of having to wait for a 2- or 24-hour urine collection. The ratio is increased in certain conditions other than acute
pancreatitis, such as diabetic acidosis and renal insufficiency. Although the usefulness of this test in pancreatic disease
has been questioned, it can be helpful to screen for macroamylasia.
Reference Values
Normal
Amylase/creatinine clearance ratio: 1%–4% or 0.01–0.04 clearance fraction
This is a ratio calculated as follows:

Urine Amylase
2-hour specimen: 2–34 U or 16–283 nkat/hour
24-hour specimen: 24–408 U or 400–6800 nkat/day
Values vary according to laboratory methods used. Check with your lab.

NOTE
kat = katal, which is a measure of enzyme activity.
Procedure
For the amylase clearance test, a venous blood sample of 4 mL must be collected at the same time the random urine
specimen is obtained.
1.
2.
3.
4.

Order a random, 2-hour, or 24-hour timed urine specimen. A 2-hour specimen is usually collected.
Refrigerate the urine specimen. Amylase is unstable in acidic urine. The pH must be adjusted to pH > 7.0.
Follow general instructions for the appropriate urine collection.
Record exact starting and ending times on the specimen container and on the health care record. This is very
important for calculation of results.
5. Send the specimen to the laboratory.
Clinical Implications
1. Amylase/creatinine clearance is increased in:
a. Pancreatitis, pancreatic cancer
b. Diabetic ketoacidosis (some patients)
c. Toxemia of pregnancy, hyperemesis of pregnancy
d. Renal insufficiency
2. Amylase/creatinine clearance is decreased in macroamylasia.

3. Urine amylase is increased in:
a. Pancreatitis
b. Parotitis
c. Intestinal obstruction
d. Diabetic ketoacidosis
e. Strangulated bowel
f. Pancreatic cyst
g. Peritonitis
h. Biliary tract disease
i. Some lung and ovarian tumors
4. Urine amylase is decreased in:
a. Pancreatic insufficiency
b. Advanced cystic fibrosis
c. Severe liver disease
d. Renal failure
e. Macroamylasemia
Interfering Factor
1. Acid pH—decreases urine amylase.
2. Some drugs produce increased amylase and possible pancreatitis.
Interventions
Pretest Patient Preparation
1. Instruct the patient about the test purpose and procedure for urine specimen collection. A written instruction sheet
may be helpful.
2. Encourage fluids, if they are not restricted.
3. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and monitor appropriately.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
Follow-up calcium levels should be checked in fulminating pancreatitis because extremely low calcium levels can
occur.
Phenylketonuria (PKU); Urine Phenylalanine (Random Urine and Blood)
Routine blood and urine tests are done on newborns to detect phenylketonuria (PKU), an inherited disease that can lead
to mental retardation and brain damage if untreated. This disease is characterized by a lack of the enzyme that converts
phenylalanine, an amino acid, to tyrosine, which is necessary for normal metabolic function. Because dietary
phenylalanine is not converted to tyrosine, phenylalanine, phenylpyruvic acid, and other metabolites accumulate in blood
and urine. Tyrosine and the derivative catecholamines are deficient, which results in mental retardation. Both sexes are
affected equally, with most cases occurring in persons of northern European ancestry.
This test is used for newborns to detect the metabolic disorder hyperphenylalaninemia. If untreated, this disorder can
lead to mental retardation. Dietary restrictions of phenylalanine have shown good results.
Reference Values
Normal
Blood: <2 mg/dL (2–5 days after birth) or <121 µmol/L
Urine: Negative dipstick (detects phenylalanine in range of 5–10 mg/dL or 302–605 µmol/L)
24-hour urine: 1.2–1.7 mg/24 hours (10 days to 7 weeks after birth) or 7.2–10.3 µmol/day
Adults: <16.5 mg/24 hours or <100 µmol/day
Children (3–12 years old): 4.0–17.5 mg/24 hours or 24–106 µmol/day
Procedure
Collecting the Blood Sample
1. Cleanse the skin with an antiseptic and pierce the infant's heel with a sterile disposable lancet.
2. Support the infant, if bleeding is slow, so that the blood flows by means of gravity while spotting the blood with filter
paper.
3. Fill the circles on the filter paper completely. This can best be done by placing one side of the filter paper against
the infant's heel and watching for the blood to appear on the other side of the paper until it completely fills the
circle.
4. Do not touch blood circles until they are completely dry. Keep in cool, dry area.
5. Transport samples to testing site within 12 to 24 hours.
6. Confirm all positive filter paper tests with a quantitative blood or urine test.
Collecting the Urine Sample in Nursery or at Home

1. Dip the reagent strip into a fresh sample of urine or press it against a wet diaper (phenylalanines and phenylpyruvic
acid may not appear in urine until the infant is 2 to 3 weeks of age).
2. After exactly 30 seconds, compare the strip with a color chart according to manufacturer's directions.
3. Salicylates and phenothiazine may cause abnormal color reactions.
4. All positive tests must be confirmed with a quantitative chemical test.
Clinical Implications Increased phenylalanine is found in:
1. Hyperphenylalaninemia. In a positive test for PKU, the blood phenylalanine is > 15 mg/dL or > 907 µmol/L. Blood
tyrosine is < 5 mg/dL or < 276 µmol/L; it is never increased in PKU.
2. Obesity
3. In low-birth-weight or premature infants, transient hyperphenylalaninemia, along with transient hypertyrosinemia,
may occur.
Interfering Factors
1. Premature infants, those weighing < 2.3 kg (<5 pounds), may have elevated phenylalanine and tyrosine levels
without having the genetic disease. This is a result of delayed development of appropriate enzyme activity in the
liver (liver immaturity).
2. Antibiotics interfere with the blood assay.
3. Cord blood cannot be used for analysis.
4. Two days of protein feeding must be done before blood is taken.
Instructions to Mothers
1. Inform the mother about the purpose of the test and the methods of collecting the specimens.
2. Most parents are interested to know that PKU (a genetic disease in which a defective gene is passed on from each
parent) was first recognized by a young mother of two mentally retarded children. She was aware that the urine of
these children had a peculiar odor and, on the basis of this, was able to have a biochemist study the urine and
identify phenylpyruvic acid. Her discovery led to the first successful dietary treatment, restriction of phenylalanine
(eg, in milk) for those newborn babies identified as having PKU. This resulted in normal mental development of
these children.
3. Interpret test outcomes and counsel regarding diet if results are positive.

Clinical Alert
The established standard is that all newborn infants should be tested for PKU and congenital hypothyroidism before
discharge.
1. The blood test must be performed at least 3 days after birth or after the child has ingested protein (milk) for at
least 24 to 48 hours.
2. Urine testing is usually done at the 4- or 6-week checkup if a blood test was not done.
3. PKU studies should be done on all infants who weigh = 2.3 kg (=5 pounds) before they leave the hospital.
4. Sick or premature infants should be tested within 7 days after birth regardless of protein intake, weight, or
antibiotic therapy.
D-Xylose Absorption (Timed Urine and Blood)
The D-xylose test is a diagnostic measure for evaluating malabsorptive conditions and intestinal absorption of D-xylose,
a pentose not normally present in the blood in significant amounts. It is passively absorbed in the proximal small bowel,
passes unchanged in the liver, and is excreted by the kidneys.
This test directly measures intestinal absorption. When D-xylose (which is not metabolized by the body) is administered
orally, blood and urine levels are checked for absorption rates. Absorption is normal in pancreatic insufficiency but is
impaired in intestinal malabsorption. It is a reliable index of the functional integrity of the jejunum in pediatric patients.
Reference Values
Normal Blood
1-hour absorption of 5-g dose—infant: >15 mg/dL or >1.0 mmol/L
1-hour absorption of 5-g dose—child: >20 mg/dL or >1.3 mmol/L
2-hour absorption of 5-g dose—adult: >20 mg/dL or >1.3 mmol/L
2-hour absorption of 25-g dose—adult: >25 mg/dL or >1.6 mmol/L
Urine Xylose 5-Hour Reference Range for 25-g dose
Child: 16%–33% of 5-g dose
Adult: >16% of 5-g dose or >4.0 g of max (0.5 g/kg to a maximum of 25 g)
Adult, 65 years of age and older: >14% of dose or >3.5 g of maximum
Procedure
1. Have the patient refrain from foods containing pentose for 24 hours before test.
2. Do not allow food or liquids by mouth for at least 8 hours before the start of the test. Pediatric patients should fast
only 4 hours.
3. Have the patient void at the beginning of the test. Discard this urine.
4. Administer the oral dose of D-xylose after it has been dissolved in 100 mL of water. Adult dosage is 25 g; for

children younger than 12 years of age, a 5-g oral dose is recommended. For adults, additional water up to 250 mL
should be taken at this time and another 250 mL in 1 hour. Record these times on the patient's health care record.
Give no further fluids (except water) or food until the test is completed.
5. Draw a 3-mL sample of venous blood within 60 to 120 minutes later.
6. Have the patient rest quietly in one place until the test is completed.
7. Have the patient void 5 hours from the start of the test. Save all urine voided during the test.
Clinical Implications
1. Urine D-xylose is decreased in:
a. Intestinal malabsorption
b. Impaired renal function
c. Small bowel ischemia
d. Whipple's disease
e. Viral gastroenteritis (vomiting)
f. Bacterial overgrowth in small intestine.
2. The D-xylose test is normal in the following conditions:
a. Malabsorption due to pancreatic insufficiency
b. Postgastrectomy
c. Malnutrition
Interfering Factors
1.
2.
3.
4.
5.
6.

Many drugs and antibiotics (see Appendix J)
Nonfasting state, treatment with hyperalimentation
Foods rich in pentose (fruits and preserves)
Vomiting of the xylose test meal (25-g dose may cause gastrointestinal distress).
Impaired renal function—use serum test only
In adults, the serum test has little value—use 5-hour urine test.

Interventions
Pretest Patient Preparation
1. Explain purpose and procedure of the test and the urine collection process. The entire 5-hour specimen must be
collected.
2. The patient must fast at least 8 hours before the start of the test; children younger than 9 years of age should fast
for only 4 hours.
3. Water may be taken at any time.
4. Weigh the patient to determine the proper dose of D-xylose.
5. The patient must not ingest contraindicated drugs for 1 week before the test.
6. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Normal food, fluids, and activities can be resumed.
2. See Chapter 1 guidelines for safe, effective, informed posttest care .

Clinical Alert
Nausea, vomiting, and diarrhea may result from ingestion of the D-xylose. If vomiting occurs, the test is invalid and
must be repeated. A 5-gram dose is more tolerated but is less sensitive.
Urine Creatinine; Creatinine Clearance (Timed Urine and Blood)
Creatinine is a substance that, in health, is easily excreted by the kidney. It is the byproduct of muscle energy metabolism
and is produced at a constant rate according to the muscle mass of the individual. Endogenous creatinine production is
constant as long as the muscle mass remains constant. Because all creatinine filtered by the kidneys in a given time
interval is excreted into the urine, creatinine levels are equivalent to the glomerular filtration rate (GFR). Disorders of
kidney function prevent maximum excretion of creatinine. The creatinine clearance test is part of most batteries of
quantitative urine tests. Creatinine clearance is measured together with other urinary components in order to interpret the
overall excretion rate of the various urinary components.
The creatinine clearance test is a specific measurement of kidney function, primarily glomerular filtration. It measures the
rate at which the kidneys clear creatinine from the blood. In a broad sense, clearance of a substance may be defined as
the imaginary volume (in milliliters) of plasma from which the substance would have to be completely extracted in order
for the kidney to excrete that amount in 1 minute. In addition to estimating the GFR, this test is used to evaluate renal
function in patients.
Because the excretion of creatinine in a given person is relatively constant, the 24-hour urine creatinine level is used as
a check on the completeness of a 24-hour urine collection. It is of no help in the evaluation of renal function unless it is
done as part of a creatinine clearance test.
Reference Values
Normal

Urine creatinine, men: 14–26 mg/kg/24 hours or 124–230 µmol/kg/day
Urine creatinine, women: 11–20 mg/kg/24 hours or 97–177 µmol/kg/day
Blood creatinine: 0.8–1.2 mg/dL or 71–106 µmol/L ( Table 3.12)
Table 3.12 Mean Creatinine Clearance (mL/min/1.73 m 2) *
Age (y) Men
20–30

90–140 or 0.8–1.3 mL/sec/m 2

Women
72–110 or 0.69–1.06 mL/sec/m 2

59–137 or 0.5–1.3 mL/sec/m 2
71–121 or 0.68–1.17 mL/sec/m 2
*Values slowly increase to adult levels, then slowly decrease each decade thereafter (the decrease per decade is
approximately 6.5 mL/min/1.73 m 2 or 0.06 mL/sec/m 2).
30–40

Procedure
1.
2.
3.
4.
5.
6.
7.

Properly label a 12-hour or 24-hour urine container.
Refrigerate or ice the specimen.
Follow general instructions for 24-hour urine collection (see Long-Term, Timed Urine Specimen, page 171).
Record exact starting and ending times on the specimen container and in the patient's health care record.
Send the entire specimen to the laboratory.
Obtain a 5-mL venous blood sample for creatinine when the test begins.
Record the patient's height and weight on the container and in the patient's health care record. Creatinine
clearance values are based on the body surface area, and these values are needed to calculate the surface area.
8. Ensure that the patient is adequately hydrated throughout the test to provide proper urine flow.
Clinical Implications
1. Decreased creatinine clearance is found in any condition that decreases renal blood flow:
a. Impaired kidney function, intrinsic renal disease, glomerulonephritis, pyelonephritis, nephrotic syndrome, acute
tubular dysfunction, amyloidosis, interstitial nephritis
b. Shock, dehydration
c. Hemorrhage
d. Chronic obstructive lung disease
e. Congestive heart failure
2. Increased creatinine clearance is found in:
a. State of high cardiac output
b. Pregnancy
c. Burns
d. Carbon monoxide poisoning
3. Increased urine creatinine is found in:
a. Acromegaly
b. Gigantism
c. Diabetes mellitus
d. Hypothyroidism
4. Decreased urine creatinine is found in:
a. Hyperthyroidism
b. Anemia
c. Muscular dystrophy
d. Polymyositis, neurogenic atrophy
e. Inflammatory muscle disease
f. Advanced renal disease, renal stenosis
g. Leukemia
Interfering Factors
1.
2.
3.
4.

Exercise may increase creatinine clearance and urine creatinine.
Pregnancy substantially increases creatinine clearance.
Many drugs decrease creatinine clearance (see Appendix J).
The creatinine clearance overestimates the GFR when there is severe renal impairment. The serum creatinine is
more indicative of the GFR in this situation.
5. A diet high in meat may elevate the urine creatinine concentration.
6. Proteinuria and advanced renal failure make creatinine clearance an unreliable method for determining GFR.

Clinical Alert
Determination of urine creatinine is of little value for evaluating renal function unless it is done as part of a creatinine
clearance test.
Interventions
Pretest Patient Preparation
1. Instruct the patient about the purpose and procedure of the test and urine specimen collection. A written reminder
may be helpful.
2. Allow food and encourage fluids for good hydration. Large urine volumes ensure optimal test results. Avoid tea and

3.
4.
5.
6.

coffee (diuretics).
Avoid vigorous exercise during the test.
Drugs affecting the results should be stopped beforehand (especially adrenocorticotropic hormone [ACTH],
cortisone, or typoxine). Check with physician.
Avoid eating large amounts of meat. Check with physician.
See Chapter 1 guidelines for safe, effective, informed pretest care.

Posttest Patient Aftercare
1. The patient may resume normal food, fluids, and activity.
2. Interpret test outcomes and monitor appropriately.
3. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Urine Cystine (Random and 24-Hour)
Cystinuria is a condition characterized by increased amounts of the amino acid cystine in the urine. The presence of
increased urinary cystine is caused not by a defect in the metabolism of cystine but rather by the inability of the renal
tubules to reabsorb cystine filtered by the glomeruli. The tubules fail to reabsorb not only cystine but also lysine,
ornithine, and arginine; this rules out the possibility of an error in metabolism, even though the condition is inherited.
These urine tests are useful for the differential diagnosis of cystinuria, an inherited disease characterized by bladder
calculi (cystine has low solubility). Patients with cystine stones face recurrent urolithiasis and repeated urinary infections.
Reference Values
Normal
Random specimen: Negative
24-hour specimen, adult: <38 mg/24 hours or <316 µmol/day
24-hour specimen, child: 5–31 mg/24 hours or 42–258 µmol/day
Procedure
1. Obtain a random 20-mL urine specimen for a qualitative screening test.
2. When collecting a 24-hour urine specimen, the container needs a preservative (toluene). Follow general
procedures for a 24-hour urine specimen (see Long-Term, Timed Urine Specimen, page 171).
Clinical Implications
1. Urine cystine is increased in cystinuria (up to 20 times normal).
2. Urine cystine is decreased in burn patients.

Clinical Alert
1. Cystinosis, a different entity from cystinuria, is not detected by cystine studies. Most patients with infantile
nephropathic cystinosis have neurologic defects that become apparent in infancy. Failure to thrive and renal
dysfunction are evidence of this disease.
2. Patients with cystinosis have a defect in renal tubular reabsorption that develops into Fanconi's syndrome, which
leads to a generalized amino aciduria. Cystine is elevated in the urine in the same proportion as all amino acids;
the concentration is not high enough to form cystine stones. Plasma cystine is normal, but cystine is elevated in
kidneys, eyes, spleen, and bone marrow; for purposes of diagnosis, it is usually measured in WBCs.
Interventions
Pretest Patient Preparation
1. Explain test purpose and procedure for timed urine collection.
2. See Chapter 1 guidelines regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and counsel appropriately.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Urine Hydroxyproline (Timed Urine and Blood)
Hydroxyproline is an amino acid found only in collagen. It increases during periods of rapid growth, in bone diseases,
and in some endocrine disorders. Urine hydroxyproline is almost entirely peptide bound, and only 10% is in the free form.
Total hydroxyproline is considered to be a marker for bone resorption because 50% of human collagen resides in bone.
This test indicates the presence of reabsorption of bone collagen in various disorders and evaluates the degree of
destruction from primary or secondary bone tumors. Free hydroxyproline is used as an aid to diagnose
hydroxyprolinemia, a rare genetic disorder characterized by mental retardation and thrombocytopenia.

NOTE
During periods of rapid growth in early childhood and in puberty, total hydroxyproline is greatly increased.

Reference Values
Normal Urine:
Total hydroxyproline (24-hour): 15–45 mg/24 hours or 115–345 µmol/day
Adult females: 0.4–2.9 mg/2-hour specimen or 3–22 µmol/2 hours
Adult males: 0.4–5.0 mg/2-hour specimen or 3–38 µmol/2 hours
Children < 5 years old: 100–400 µg/mg creatinine or 86–345 mmol/day
Children 5–12 years: 100–150 µg/mg creatinine or 86–129 mmol/day
Blood (Plasma)—Free Hydroxyproline:
Newborn: 0.52 ± 0.52 mg/dL or 40 ± 40 µmol/L
Child (male): <0.66 mg/dL or <50 µmol/L
Child (female): <0.58 mg/dL or <44 µmol/L
Adult (male): <0.55 mg/dL or <42 µmol/L
Adult (female): <0.45 mg/dL or <34 µmol/L
Procedure
1. Obtain a 2-hour specimen after the patient has fasted overnight (preferred method).
2. Notify the laboratory of the patient's age and sex.
3. If ordered, collect a 24-hour urine specimen. No preservative is required, but the specimen must be refrigerated or
placed on ice.
4. Follow 24-hour urine collection procedures. The laboratory will record the total 24-hour volume.
5. Note that the preferred method of testing in the first few months of life is blood sampling (free hydroxyproline only
for genetic screening).
Clinical Implications
1. Free hydroxyproline is increased in:
a. Hydroxyprolinemia, a hereditary autosomal recessive condition (very rare)
b. Familial iminoglycinuria, also inherited and rare
2. Total hydroxyproline is increased in:
a. Hyperparathyroidism, hyperthyroidism
b. Paget's disease—measures the severity and the response to treatment
c. Marfan's syndrome, acromegaly
d. Osteoporosis
e. Myeloma
f. Severe burns
3. Total hydroxyproline is increased in:
a. Hypopituitarism
b. Hypothyroidism
c. Hypoparathyroidism
Interfering Factors
1. Gelatin may affect test results (false-positive test). For best results, the patient should be on a nonprotein diet.
2. Bed rest increases values
3. Pregnancy increases values
Interventions
Pretest Patient Preparation
1. Explain the test purpose and procedure for a timed urine collection. Fasting and special fluid requirements before
testing are often required for a 24-hour timed procedure. Check with laboratory.
2. Avoid gelatin foods for several days before the test.
3. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. The patient may resume normal diet and activity.
2. Interpret test outcomes and counsel appropriately.
3. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Urine Lysozyme (Random, 24-Hour Urine, and Blood)
Lysozyme (muramidase) in blood or urine is a bacteriolytic enzyme that comes from degradation of granulocytes and
monocytes, but not lymphocytes. It is increased in leukemia owing to degradation of granulocytic or monocytic cells.
This blood and urine test differentiates acute myelogenous or monocytic leukemia from acute lymphatic leukemia. It is
useful to monitor the response to treatment of acute myelogenous and active monocytic leukemia.
Reference Values
Normal
Blood plasma: 0.4–1.3 mg/dL or 4–13 mg/L
Urine, 24-hour specimen: 0–3 mg/24 hours
Reference values are not established for random urine specimens.
Procedure

1. Collect a 5-mL EDTA-anticoagulated blood sample or urine specimen.
2. Follow general instructions for 24-hour urine collections. Transport the sample to the laboratory immediately after
collection.
Clinical Implications
1. Lysozyme levels are increased in:
a. Acute myelogenous leukemia (granulocytic)
b. Acute monocytic leukemia
c. Malignant histiocytosis
2. Lysozyme levels may be increased in:
a. Renal disorders and transplant rejection
b. Tuberculosis
c. Sarcoidosis (sarcoid lymph nodes)
d. Crohn's disease
e. Polycythemia vera
3. Lysozyme levels are normal in acute lymphatic leukemia.
4. Lysozyme levels are decreased in neutropenia with hypoplasia of bone marrow.
Interventions
Pretest Patient Preparation
1. Explain the test purpose and procedure for urine or blood collection.
2. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and counsel appropriately.
2. Follow Chapter 1 guidelines for safe, effective, informed posttest care .
Urine Amino Acids, Total and Fractions (Random, 24-Hour Urine, and Blood)
Many abnormalities in amino acid transport or metabolism can be detected by physiologic fluid analysis (urine, plasma,
or cerebrospinal fluid). Free amino acids are found in urine and in acid filtrates of protein-containing fluids. Urine is used
for initial screening of inborn metabolic errors. Both transport errors and metabolic errors can be detected by changes in
observed amino acid patterns. In many cases, metabolic errors are detected when amino acid or metabolite exceeds its
renal threshold.
This test is useful for the diagnosis and monitoring of inborn errors of metabolism and transport in cases of suspected
genetic abnormalities in patients with mental retardation, reduced growth, or other unexplained symptoms. More than 50
aminoacidopathies are now recognized.
Reference Values
Normal
Urine and blood amino acid values are age dependent.
Procedure
1. Obtain a fasting blood specimen.
2. Collect a random 24-hour timed urine specimen. Keep the specimen refrigerated or on ice.
Clinical Implications
1. Total plasma amino acids are increased in:
a. Specific aminoacidopathies ( Table 3.13)
Table 3.13 Aminoacidurias
Aminoacidurias

Amino Acids Increased in Urine and Blood

Presence of Abnormal Enzymes

Phenylketonuria
Tyrosinosis

Phenylketonuria
Tyrosine

Histidinemia
Maple syrup urine
disease
Hypervalinemia
Hyperglycinemia

Histidine
Valine, leucine, and isoleucine

Phenylamine hydroxylase
p-Hydroxyphenyl-pyruvic acid
oxidase
Histidase
Branched chain ketoacid
decarboxylase
Probably valine transaminase
Increased glycine and propionic
acid

Valine
Glycine (lysine on high-protein diet)

Hyperprolinemia
Type I
Type II

Proline

Hydroxyprolinemia

Hydroxyproline

Proline oxidase
pyrroline-5-carboxylate
dehydrogenase
Hydroxyproline oxidase

Homocystinuria
Hyperlysinemia
Citrullinemia
Alkaptonuria
Oasthouse urine
disease

Methionine, homocystine
Lysine
Citrulline
Homogentisic acid (2,5-dihydroxyphenylacetic
acid); no abnormal amino acid
Methionine, phenylalanine, valine, leucine,
isoleucine, and tyrosine, and also a-hydroxybutyric
acid in urine

Cystathionine synthetase
Lysine-a-ketoglutarate reductase
Argininosuccinic acid synthetase
Homogentisic acid oxidase
Possibly methionine
malabsorption syndrome

b. Secondary causes
1. Diabetes with ketosis
2. Malabsorption
3. Hereditary fructose intolerance
4. Conditions with severe brain damage
5. Reye's syndrome
6. Acute and chronic renal failure
7. Eclampsia
8. Specific aminoacidopathies
2. Total plasma amino acids are decreased in:
a. Adrenocortical hyperfunction
b. Huntington's chorea
c. Phlebotomus fever
d. Nephritic syndrome
e. Rheumatoid arthritis
f. Hartnup's disease
3. Total urine amino acids are increased in specific aminoacidurias (see Table 3-13).
4. Absence of amino acids occurs as listed in Table 3-14.
Table 3.14 Absence of Amino Acids
Disease

Amino Acids in Urine

Presence of Abnormal Exzyme

Argininosuccinic aciduria
Cystathionunuria
Homocystinuria
Hypophosphatasia

Argininosuccinic acid (also citrulline)
Cystathionine
Homocystine
Phosphoethanolamine

Argininosuccinase
Cystathionines
Cystathionine synthetase
Serum alkaline phosphate

5. Renal transport aminoacidurias include the elements listed in Table 3-15.
Table 3.15 Renal Transport Aminoacidurias
Disease

Amino Acids in Urine

Abnormality

Cystinuria
(cystine
stones)
Hartnup's
disease

Cystine; lysine; arginine, ornithine (basic amino
acids)

Incomplete absorption of cystine, lysine,
arginine, ornithine

Monoaminomonocarboxylic (neutral) amino acids
(proline, glycine, hydroxyproline, and methionine not
increased)
Glycine—proline, hydroxyproline

Incomplete absorption of
monoaminomonocarboxyamino acids

Glycinuria,
renal type
Familial iminoglycinuria

Membrane transport defect

6. Secondary aminoacidurias occur in the following:
a. Viral hepatitis
b. Multiple myeloma
c. Hyperparathyroidism
d. Rickets (vitamin D resistant)
e. Osteomalacia
f. Hereditary fructose intolerance
g. Galactosemia
h. Liver disease or necrosis
i. Renal failure, renal disease
j. Cystinosis
k. Muscular dystrophy (progressive)
Interfering Factors
1. Amino acid concentration displays a marked circadian rhythm—30% variation, highest in midafternoon and lowest
in morning.
2. Hyperalimentation and intravenous therapy affect outcome.
3. Drugs such as amphetamines, norepinephrine, levodopa, and all antibiotics affect results.
4. Age is a significant factor, especially in newborns and infants.

5. Pregnancy decreases values.
Interventions
Pretest Patient Preparation
1. Genetic counseling is recommended before specimen collection.
2. Instruct the patient regarding the test purpose, collection procedure, and need for refrigeration. A written reminder
may be helpful.
3. Allow foods and moderate amounts of fluids (do not overhydrate).
4. It may be necessary to consume proteins or carbohydrates for a challenge load to produce certain amino acid
metabolites.
5. See Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and counsel appropriately. Genetic counseling may be necessary.
2. Follow Chapter 1 guidelines regarding safe, effective, informed posttest care.
BIBLIOGRAPHY
Ali A: Proteinuria: How much evaluation is appropriate? Postgrad Med 101: 173, 1997
Belsey R, Baer DM: Specimen collection for diagnosing UTI. Medical Laboratory Observer 28: 29, 1996
Cooper C: What color is that urine specimen. Am J Nurs 93(8): 37, 1990
Finnegan K: Correlating routine urinalysis with selected kidney disorders. Advances for Laboratory Professionals 2(12), June 1999
Goroll AH, May LA, Mully AG Jr: Primary Medicine, 4th ed. Philadelphia, Lippincott Williams & Wilkins, 2000
Graff L: Handbook of Routine Urinalysis. Philadelphia, JB Lippincott, 1983
Klee GG: Maximizing Efficacy of Endocrine Tests: Importance of Decision-focused Testing Strategies and Appropriate Patient Preparation. Clin
Chem 45(8): 1323–1330, Special Issue 1999, Part 2 of 2, Proceedings of the Twenty-Second Annual Arnold O. Beckman Conference in Clinical
Chemistry Feb 21–22, 1999
Kunin CM: Urinary Tract Infections: Detection, Prevention, and Management, 5th ed. Baltimore, Williams & Wilkins, 1996
Leavelle DE: Interpretive Data for Diagnostic Laboratory Tests. Rochester, MN, Mayo Medical Laboratories, 2001
Lehmann CA (ed): Saunders Manual of Clinical Laboratory Science. Philadelphia, WB Saunders, 1998
Marchiondo K, Credit CE: A new look at urinary tract infections. Am J Nurs 98(3): 34–39, 1998
McBride LJ: Textbook of Urinalysis and Body Fluids. Philadelphia, Lippincott Williams & Wilkins, 1998
Newland JA: Cystitis in women. Am J Nurs 98(1): 16AAA, 1998
Quantimetrix Corporation: Urinalysis Made Simple. Redondo Beach, CA, Author, 2000
Speicher CE: The Right Test: A Physician's Guide to Laboratory Medicine, 3rd ed. Philadelphia, WB Saunders, 1998
Strasinger SK: Urinalysis and Body Fluids, 4th ed. Philadelphia, FA Davis, 2001
Thompson WG: Things that go red in the urine; and others that don't. Lancet 347: 5, 1996
Tietz N: Clinical Guide to Laboratory Tests, 3rd ed. Philadelphia, WB Saunders, 1995
Toffaletti J: Renal Function and Failure. Washington, DC, AACC Press, 1999
Wallach J: Interpretation of Diagnostic Tests, 7th ed. Philadelphia, Lippincott Williams & Wilkins, 2000
Young DS: Effects of Drugs on Clinical Laboratory Tests, 5th ed. Washington, DC, AACC Press, 1999

4 Stool Studies
A Manual of Laboratory and Diagnostic Tests

4
Stool Studies
OVERVIEW OF STOOL STUDIES
STOOL ANALYSIS
Random Collection and Transport of Stool Specimens
Collection and Transport of Specimens for Ova and Parasites
Collection and Transport of Specimens for Enteric Pathogens
STOOL STUDIES
Stool Consistency, Shape, Form, Amount, and Odor
Stool Color
Blood in Stool; Occult Blood
Apt Test for Swallowed Blood
Mucus in Stool
Stool pH
Stool Reducing Substances Test
Leukocytes in Stool
Collection and Transport of 24-, 48-, 72-, and 96-Hour Stool Specimens
Fat in Stool; Fecal Fat Stain
Meat Fibers in Stool; Stool Muscle Fiber
Urobilinogen in Stool
Trypsin in Stool: Fecal Chymotrypsin
Procedural Alert
Stool Electrolytes: Sodium, Chloride, Potassium, and Osmolality
BIBLIOGRAPHY

OVERVIEW OF STOOL STUDIES
The elimination of digestive waste products from the body is essential to health. These excreted waste products are
known as stool or feces. Stool examination is often done for evaluation of gastrointestinal (GI) disorders. These studies
are helpful in detecting GI bleeding, GI obstruction, obstructive jaundice, parasitic disease, dysentery, ulcerative colitis,
and increased fat excretion. (See Stool Analysis on p. 266.)
An adult excretes 100 to 200 g of fecal matter a day, of which as much as 75% may be water. The feces are what remain
of the 8 to 10 L of digested fluid-like material that enters the intestinal tract each day, and oral food and fluids, saliva,
gastric secretions, pancreatic juice, and bile add to the formation of feces.
Feces are composed of the following materials:
1.
2.
3.
4.
5.
6.
7.
8.

Waste residue of indigestible material (eg, cellulose) from food eaten during the previous 4 days
Bile (pigments and salts): stool color is normally due to bile pigments that have been altered by bacterial action.
Intestinal secretions
Water and electrolytes
Epithelial cells that have been shed
Large numbers of bacteria
Inorganic material (10%–20%), chiefly calcium and phosphates
Undigested or unabsorbed food (normally present in very small quantities)

The output of feces depends on a complex series of absorptive, secretory, and fermentative processes. Normal function
of the colon involves three physiologic processes: (1) absorption of fluid and electrolytes; (2) contractions that churn and
expose the contents to the GI tract mucosa and transport the contents to the rectum; and (3) defecation.
The small intestine is approximately 23 feet (7 m) long, and the large intestine is 4 to 5 feet (1.2–1.5 m) long. The small
intestine degrades ingested fats, proteins, and carbohydrates to absorbable units and then absorbs them. Pancreatic,
gastric, and biliary secretions exert their effects on the GI contents to prepare this material for active mucosal transport.
Other active substances absorbed in the small intestine include fat-soluble vitamins, iron, and calcium. Vitamin B 12, after
combining with intrinsic factors, is absorbed in the ileum. The small intestine also absorbs as much as 9.5 L of water and
electrolytes for return to the bloodstream. Small intestine contents (ie, chyme) begin to enter the rectum as soon as 2 to 3
hours after a meal, but the process is not complete until 6 to 9 hours after eating.
The large intestine performs less complex functions than the small intestine. The proximal or right colon absorbs most of
the water remaining after the GI contents have passed through the small intestine. Colonic absorption of water, sodium,
and chloride is a passive process. Fecal water excretion is only about 100 mL/day. The colon mainly moves the luminal
contents to and fro by seemingly random contractions of circular smooth muscle. Increased propulsive activity (ie,
peristalsis) occurs after eating. Peristaltic waves are caused by the gastrocolic and duodenocolic reflexes, which are
initiated after meals and stimulated by the emptying of the stomach into the duodenum. The muscles of the colon are
innervated by the autonomic nervous system. Additionally, the parasympathetic nervous system stimulates movement,
and the sympathetic system inhibits movement. Massive peristalsis usually occurs several times a day. Resultant
distention of the rectum initiates the urge to defecate. In persons with normal motility and a mixed dietary intake, normal

colon transit time is 24 to 48 hours.

STOOL ANALYSIS
Stool analysis determines the various properties of the stool for diagnostic purposes. Some of the more frequently
ordered tests on feces include tests for leukocytes, blood, fat, ova, parasites, and pathogens ( Table 4.1). (Stool culture
is explained in Chap. 7, Microbiologic Studies.) Stool is also examined by chromatographic analysis for the presence of
gallstones. The recovery of a gallstone from feces provides the only proof that a common bile duct stone has been
dislodged and excreted. Stool testing also screens for colon cancer and asymptomatic ulcerations or other masses of the
GI tract and evaluates GI diseases in the presence of diarrhea and/or constipation. Stool testing is done in
immunocompromised persons for parasitic diseases. Fat analysis is used as the gold standard to diagnose
malabsorption syndrome.

Table 4.1 Stool Testing for Infections
Source of Stool Infection

Clinical Signs or
Symptoms

Laboratory Test (Sequence or
Follow-up)

Community Acquired from intermediate hosts, ie:
Home—pets, dogs, contaminated water
Occupational
Fishing—snails and worms
Meat cutters—from contaminated animals
Health care workers—from patients
Farm workers—animals (cows, pigs), garden, flies,
mosquitoes, insects, fleas, bugs
Recreational—backpacking, poor sanitation
Travel—Third World—contaminated water supply
Contact with fair animals
Hookworm infection—not fecal or oral; it is direct penetration
of skin by larva in contaminated soil or in animal droppings

Diarrhea, bloody,
purulent
Steatorrhea
Cramping, bloating,
belching
Small bowel
obstruction, weight
loss
Generalized skin
rash
Huge swelling of
legs, arms, or
scrotum
Huge lymphatic
swelling
Fever, chills, night
sweats
Diarrhea
Medication history
of antibiotic use

Screen stool for ova and parasites
Microscopic exam of stool for ova
and parasites
Stool culture— Clostridium difficile
assay (some patients may require
more than one assay)
Eosinophilia in blood sample
Exam for worms in stool or around
anus
Fecal smear for leukocytes and
yeast

Nosocomial Acquired from institutions such as hospitals or
nursing homes

Personal Contact with an infected host when patient is
compromised (weakened immune system, ie, HIV) or
debilitated as in frail children or elderly

Eosinophilia in blood sample
Exam for worms in stool or around
anus
Microscopic exam of stool for ova
and parasites
Stool culture for Clostridium difficile
Fecal smear for leukocytes and
yeast
Screen stool for ova and parasites
Microscopic exam of stool for ova
and parasites
Stool culture for Clostridium difficile
Toxin stool assay
Acid-fast bacilli (AFB) in stool for
tuberculosis
Microsporidium

Patients and health care personnel may dislike collecting and examining fecal material; however, this natural aversion
must be overcome in light of the value of a stool examination for diagnosing disturbances and diseases of the GI tract,
the liver, and the pancreas.
Random Collection and Transport of Stool Specimens
1. Observe standard/universal precautions (see Appendix A) when procuring and handling specimens to avoid
infectious pathogens (eg, hepatitis A, Salmonella, and Shigella).
2. Collect feces in a dry, clean, urine-free container that has a properly fitting cover.
3. The specimen should be uncontaminated with urine or other bodily secretions such as menstrual blood. Stool can
be collected from the diaper of an infant or incontinent adult. Samples can be collected from temporary ostomy
bags.
4. While wearing gloves, collect the entire stool specimen and transfer it to a container using a clean tongue blade or
similar object. A sample 2.5-cm (1-inch) long or 64.7 mg (1 oz) of liquid stool may be sufficient for some tests.
5. For best results, cover specimens and deliver to the laboratory immediately after collection. Depending on the
examination to be performed, the specimen should be either refrigerated or kept warm. If you are unsure of how to
handle the specimen, contact the laboratory for detailed instructions concerning the disposition of the fecal
specimen before collection is begun.
6. Post signs in bathrooms that say “DO NOT DISCARD STOOL” or “SAVE STOOL” to serve as reminders that fecal

specimen collection is in progress.
Collection and Transport of Specimens for Ova and Parasites
1. Wear gloves. Observe standard precautions (see Appendix A). Collect feces in a dry, clean, urine-free container. If
unsure of how to collect specimen, contact the laboratory before collection is begun.
2. Warm stools are best for detection of ova and parasites. Do not refrigerate specimens for ova and parasites.
3. Special vials that contain 10% formalin and polyvinyl alcohol (PVA) fixative may be used for collecting stool
samples to test for ova and parasites. In this case, specimen storage temperature is not critical.
4. Because of the cyclic life cycle of parasites, three separate random stool specimens for analysis are recommended.
5. Place the specimen in a biohazard bag.
Collection and Transport of Specimens for Enteric Pathogens
1. While wearing gloves, collect feces in a dry, clean, urine-free container. If unsure of how to collect the specimen,
contact the laboratory before collection is begun. Observe standard precautions.
2. Some coliform bacilli produce antibiotic substances that destroy enteric pathogens. Refrigerate the specimen
immediately to prevent this from happening in the sample.
3. A diarrheal stool will usually give accurate results.
4. A freshly passed stool is the specimen of choice.
5. Collect stool specimens before antibiotic therapy is initiated and as early in the course of the disease as possible.
6. If mucus or blood is present, it definitely should be included with the specimen because pathogens are more likely
to be found in these substances. If only a small amount of stool is available, a walnut-sized specimen is usually
adequate.
7. Accurately label all stool specimens with the patient's name, date, and tests ordered on the specimen. Keep the
outside of the container free from contamination and immediately send the sealed container to the laboratory.
8. For best preservation and transport of pathogens, a Cary-Blair solution vial with indicator should be used.
Interfering Factors for All Types of Stool Collection
1. Stool specimens from patients receiving tetracyclines, antidiarrheal medications, barium, bismuth, oil, iron, or
magnesium may not yield accurate results.
2. Bismuth found in paper towels and toilet tissue interferes with accurate results.
3. Do not collect or retrieve stool from the toilet bowl or use a specimen that has been contaminated with urine, water,
or toilet bowl cleaner. A clean, dry bedpan may be the best receptacle for defecation.
4. Inaccurate test results may result if the sample is not representative of the entire stool evacuation.
5. Lifestyle, personal habits, travel, home and work environments, and bathroom accessibility are some of the factors
that may interfere with proper sample procurement.
6. Specimen not transported promptly. Trophozites in liquid stool disintegrate rapidly after defecation; therefore, the
specimen needs to be examined 30 minutes from start of collection of specimen, not 30 minutes from end of
collection. Semi-formed stool should be examined within 60 minutes after defecation. No trophozites are seen in
formed stool.
Interventions
Pretest Patient Preparation
1. Explain the collection purpose, procedure, and interfering factors in language the patient understands. Because the
specimen cannot be obtained on demand, it is important to provide detailed instructions before the test so that the
specimen is collected when the opportunity presents itself. Provide written instructions if necessary.
2. Provide proper containers and other collection supplies. Instruct the patient to defecate in a large-mouthed plastic
container, bag, or clean bedpan. Provide for and respect the patient's privacy.
3. Instruct the patient not to urinate into the collecting container or bedpan.
4. Do not place toilet paper in the container or bedpan because it interferes with testing.
5. If the patient has diarrhea, a large plastic bag attached by adhesive tape to the toilet seat may be helpful in the
collection process. After defecation, the bag can be placed into a gallon container.
6. Specimens for most tests can be produced by a warm saline enema or Fleet Phospho-Soda enema.
7. Tests for both ova and parasites and cultures for enteric pathogens may be ordered together. In this case, the
specimen should be divided into two samples, with one portion refrigerated for culture testing and one portion kept
at room temperature for ova and parasite testing. There are commercial collection kits that require the stool to be
divided and placed into separate vials for better recovery of ova and parasites and enteric pathogens. (See Chap.
7, Microbiologic Studies.)
8. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Provide patient privacy and the opportunity to cleanse perineal area and hands. Assist as necessary.
2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Clinical Alert
1. Any stool collected may harbor highly infective pathogens. Use extreme caution and proper handling techniques
at all times.
2. Instruct patients in proper hand-washing techniques after each use of the bathroom.

STOOL STUDIES
Stool Consistency, Shape, Form, Amount, and Odor
Inspection of the feces is an important diagnostic tool. The quantity, form, consistency, and color of the stool should be
noted. When diarrhea is present, the stool is watery. Large amounts of mushy, frothy, foul-smelling stool are
characteristic of steatorrhea. Constipation is associated with firm, spherical masses of stool. Feces have a characteristic
odor that varies with diet and the pH of the stool.
Normally, evacuated feces reflect the shape and caliber of the colonic lumen as well as the colonic motility. The normal
consistency is somewhat plastic and neither fluid, mushy, nor hard. Consistency can also be described as formed, soft,
mushy, frothy, or watery. The odor of normal stool is caused by indole and skatole, formed by bacterial fermentation and
putrefaction.
Reference Values
Normal
1. 100–200 g/d
2. Characteristic odor present; plastic, soft, formed; soft and bulky on a high-fiber diet; small and dry on a high-protein
diet; seeds and small amounts of vegetable fiber present (as opposed to muscle fiber) ( Table 4.2)
Table 4.2 Normal Values in Stool Analysis
Macroscopic Examination

Normal Value

Amount
Color
Odor
Consistency
Size and shape
Gross blood
Mucus
Pus
Parasites

100–200 g/d
Brown
Varies with pH of stool and depends on bacterial fermentation and putrefaction
Plastic; not unusual to see fiber, vegetable skins, and seeds; soft and bulky in
high-vegetable diet; small and dry in high-meat diet
Formed
None
None
None
None

Microscopic Examination

Normal Values

Fat
Undigested food, meat fibers,
starch, trypsin
Eggs and segments of
parasites
Bacteria and viruses
Yeasts
Leukocytes

Colorless, neutral fat (18%) and fatty acid crystals and soaps
None to small amount

Chemical Examination

Normal Values

Water
pH
Occult blood
Urobilinogen
Porphyrins

Up to 75%
Neutral to weakly alkaline (pH 7.0–7.5)
Negative
50–300 mg/24 h
Corporphyrins: 400–1200 µg/24 h (611–1832 nmol/d)
Uroporphyrins: 10–40 µg/24 h (12–48 nmol/d)
<2.5 g/24 h (<178 mmol/d)
Negative in adults; positive in newborns
20–95 U/g
200–250 mOsm

None
None
None
None

Nitrogen
Apt test for swallowed blood
Trypsin
Osmolality, used with stool
Na + K to calculate osmotic gap
Sodium
5.8–9.8 mEq/24 h (5.8–9.8 mmol/d)
Chloride
2.5–3.9 mEq/24 h (2.5–3.9 mmol/d)
Potassium
15.7–20.7 mEq/24 h (15.7–20.7 mmol/d)
Lipids (fatty acids)
0–6 g/24 h (0–21 mmol/d)
Carbohydrates (as reducting
<0.25 g/dL
substances)
Note: Reference values for electrolytes differ greatly from laboratory to laboratory.

Procedure Collect a random stool specimen in a plastic container.
Clinical Implications

1. Fecal consistency alterations
a. Diarrhea due to the following:
1. Infection— Salmonella, Shigella, Yersinia, human immunodeficiency virus (HIV) enteropathy, Campylobacter
2. Inflammatory disorder—Crohn's disease, ulcerative colitis
3. Steatorrhea—sprue, celiac disease
4. Carbohydrate malabsorption—lactose or sucrose deficiency
5. Endocrine abnormalities—diabetes mellitus, hyperthyroid or hypothyroid, adrenal insufficiency
6. Hormone-producing tumors—Zollinger-Ellison syndrome, gastrinoma, medullary thyroid carcinoma, villous
adenoma
7. Colon carcinoma
8. Infiltration of lesions due to lymphoma, scleroderma of bowel
9. Drugs, antibiotics, cardiac medications, chemotherapy
10. Osmotically active dietary items—sorbitol, psyllium fiber, caffeine, ethanol
11. GI surgery—gastrectomy, stomach stapling, intestinal resection
12. Factitious—self-induced laxative abuse associated with psychiatric disorders
b. “Pasty” stool associated with high-fat content can be caused by the following:
1. Common bile duct obstruction
2. Celiac disease (sprue and steatorrhea); stool resembles aluminum paint
3. Cystic fibrosis—greasy “butter” stool appearance due to pancreatic involvement
c. Bulky or frothy stool is usually due to steatorrhea and celiac disease.
2. Alterations in stool size or shape indicate altered motility or colon wall abnormalities.
a. A narrow, ribbon-like stool suggests the possibility of spastic bowel, rectal narrowing or stricture, decreased
elasticity, or a partial obstruction.
b. Excessively hard stools are usually due to increased fluid absorption because of prolonged contact of luminal
contents with colon mucosa during delayed transmit time through the colon.
c. A large-circumference stool indicates dilatation of the viscus.
d. Small, round, hard stools (ie, scybala) accompany habitual, moderate constipation.
e. Severe fecal retention can produce huge, firm, impacted stool masses with a small amount of liquid stool as
overflow. These must be removed manually, occasionally under light anesthesia.
3. Fecal odor should be assessed whenever a stool specimen is collected.
a. A foul odor is caused by dehydration of undigested protein and is produced by excessive carbohydrate
ingestion.
b. A sickly sweet odor is produced by volatile fatty acids and undigested lactose.
4. Mucus in stool occurs in constipation, malignancy, and colitis (see p. 278).
Interventions
Pretest Patient Preparation
1. Ensure that the patient avoids barium procedures and laxative preparations for 1 week before stool specimen
collection.
2. Advise the patient of the purpose of test and instruct him or her in collection techniques and refrigeration of
specimen. Provide collection container.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Assessment of Diarrhea and Constipation
1. When performing a workup for the differential diagnosis of diarrhea or constipation, a patient history is most
important. The following factors should be charted:
a. An estimate of volume and frequency of fecal output
b. Stool consistency and presence of blood, pus, mucus, oiliness, or bad odor in specimen; evaluate through direct
observation
c. Decrease or increase in frequency of defecation
d. Sensations of rectal fullness with incomplete stool evacuation
e. Painful defecation
2. Assess dietary habits and food allergies.
3. Assess emotional state of patient—psychological stress may be major cause of altered bowel habits.
4. Be alert for signs of laxative abuse.
Posttest Patient Aftercare
1. Evaluate outcome; interpret, report, and record findings. If abnormalities are detected, counsel patient
appropriately. If patient has watery diarrhea, note history of contact with affected family members, travel to a
developing country, involvement in vacation or resort backpacking, community and municipal water supply, or
contact with farm animals. Explain that additional testing (eg, colonoscopy) may be necessary.
2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Stool Color
The brown color of normal feces is probably due to stercobilin (urobilin), a bile pigment derivative, which results from the
action of reducing bacteria in bilirubin and other undetermined factors.
The first indication of GI disturbances is often a change in the normal brown color of the feces. A change in color can
provide information about pathologic conditions, organic dysfunction, or intake of drugs. Color abnormalities may aid the

clinician in selection of appropriate diagnostic chemical and microbiologic stool tests.
Reference Values
Normal Brown
Procedure Collect a random stool specimen. Observe standard precautions.
Clinical Implications The color of feces changes in some disease states is as follows:
1. Yellow, yellow-green, or green: severe diarrhea
2. Black, with a tarry consistency: usually the result of bleeding in the upper GI tract (>100 mL blood)
3. Maroon, red, or pink: possibly the result of bleeding of the lower GI tract from tumors, hemorrhoids, fissures, or an
inflammatory process
4. Clay-colored (tan-gray-white): biliary obstruction
5. Pale, with a greasy consistency: pancreatic deficiency causing malabsorption of fat

Clinical Alert
Grossly visible blood always indicates abnormal state.
1. Blood streaked on the outer surface of stool usually indicates hemorrhoids or anal abnormalities.
2. Blood present in stool can also be caused by abnormalities higher in the colon. If transmit time is sufficiently
rapid, blood from the stomach or duodenum can appear as bright red, dark red, or maroon in stool.
Interfering Factors
1. Stool darkens on standing.
2. The color of stool is influenced by diet (certain foods), food dyes, and drugs (see Appendix J).
a. Yellow-rhubarb; yellow to yellow-green color occurs in the stool of breast-fed infants who lack normal intestinal
flora.
b. Pale yellow, white, or gray stools are due to barium intake.
c. Green color occurs with diets high in chlorophyll-rich green vegetables such as spinach or with some drugs (see
Appendix J).
d. Black color may be due to foods such as cherries, an unusually high proportion of dietary meat, artificially
colored foods such as black jelly beans, or drugs and supplements such as charcoal, bismuth, or iron.
e. Light-colored stool with little odor may be due to diets high in milk and low in meat.
f. Clay-like color may be due to a diet with excessive fat intake or barium intake.
g. Red color may be due to a diet high in beets or tomatoes, red food coloring, or peridium compound.
h. Certain color changes may result from specific drugs (see Appendix J).

Clinical Alert
A complete dietary and drug history will help to differentiate significant abnormalities from interfering factors.
Interventions
Pretest Patient Preparation
1. Advise patient of purpose of test. Ask patient to notify clinician about stool color changes. Follow guidelines in
Chapter 1 for safe, effective, informed pretest care.
2. Record dietary and drug history.
3. Ensure that the patient avoids laxatives and barium procedures for 1 week before collection.
Posttest Patient Aftercare
1. Interpret and document abnormal appearance and colors of stool; counsel patient appropriately regarding the
meaning of color changes and explain need for further testing (eg, GI studies).
2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Blood in Stool; Occult Blood
The most frequently performed fecal analysis is chemical screening for the detection of occult (ie, hidden) blood.
Bleeding in the upper GI tract may produce a black, tarry stool. Bleeding in the lower GI tract may result in an overtly
bloody stool. However, no visible signs of bleeding may be present with smaller amounts of blood found in early stages of
GI diseases; thus, the chemical detection of occult blood is necessary to identify and treat disease early in its course.
Occult blood testing is also controversial owing to many false-positive and false-negative results. If the patient
preparation and collection of specimen is followed explicitly, the results are more accurate.
An average, healthy person passes up to 2.0 mL of blood per 150 g of stool into the GI tract daily. Passage of more than
2.0 mL of blood in the stool in 24 hours is pathologically significant. Detection of occult blood in the stool is very useful in
detecting early disease of the GI tract. This test demonstrates the presence of blood produced by upper GI bleeding, as
in the presence of gastric ulcer; it also screens for colonic carcinomas while they are still in the localized stages. With
proper medical follow-up, an 84% survival rate has been demonstrated for treatment of colonic carcinoma.
Reference Values
Normal Negative for blood
Procedure

1. Obtain a random stool specimen. Observe standard precautions. Tests for detecting fecal blood use the
pseudoperoxidase activity of hemoglobin reacting with hydrogen peroxide to oxidize a colorless compound to a
colored one (usually blue). Hemoccult II (Smith-Kline) is the most widely used commercial test with the lowest
percentage of false-positive results (1%–12%). This test system uses guaiac-impregnated filter paper as the
chromogen that produces the blue color in a positive reaction.
2. Apply a thin smear of stool inside the indicated circle using a wood applicator stick and allow it to dry. If stool is
bloody, the collector may be at risk for hepatitis B, hepatitis C, or HIV infection.
3. Protect the Hemoccult slide from light, heat, and humidity. Do not refrigerate.
4. Do not allow the delay between smearing the stool and testing to exceed 14 days. Do not refrigerate sample before
testing.
Clinical Implications
1. Stool that appears dark red to tarry black indicates a loss of 50.0 to 75.0 mL of blood from the upper GI tract.
Smaller quantities of blood in the GI tract can produce similar-appearing stools or appear as bright red blood.
2. A stool sample should be considered grossly bloody only after a chemical testing for presence of blood. This will
eliminate the possibility that abnormal coloring caused by diet or drugs may be mistaken for bleeding in the GI tract.
3. Positive testing for occult blood may be caused by the following conditions:
a. Carcinoma of colon
b. Ulcerative colitis and other inflammatory lesions
c. Adenoma
d. Diaphragmatic hernia
e. Gastric carcinoma
f. Rectal carcinoma
g. Peptic ulcer
h. Gastritis
i. Vasculitis
j. Amyloidosis
k. Kaposi's sarcoma

Clinical Alert
1. To be accurate, the test employed must be repeated three to six times on different stool samples; some bowel
lesions may bleed intermittently.
2. The patient's diet should be free of meat and vegetable sources of peroxidase activity (eg, turnips, horseradish,
red or rare meat, cauliflower, broccoli, cantaloupe, parsnips). Only after following this regimen can a positive
series of tests be considered an indication for further patient evaluation and testing.
Interfering Factors
1. Drugs such as salicylates (aspirin), steroids, indomethacin, nonsteroidal anti-inflammatory drugs (NSAIDs),
anticoagulants, colchicine, and antimetabolites are associated with increased GI blood loss in average, healthy
persons and with more pronounced bleeding when disease is present. GI bleeding can also follow parenteral
administration of the above-mentioned drugs and should be avoided 7 days before testing.
2. Drugs that may cause false-positive results for occult blood testing include the following:
a. Boric acid
b. Bromides
c. Colchicine
d. Iodine, povidone-iodine (Betadine)
e. See Appendix J for other drugs.
3. Foods that may cause false-positive results for occult blood testing include the following:
a. Meats, including processed meats and liver, which in the diet contain hemoglobin, myoglobin, and certain
enzymes that can give false-positive test results for up to 4 days after consumption.
b. Vegetables and fruits with peroxidase activity (eg, turnips, horseradish, mushrooms, broccoli, apples, radishes,
bananas, cantaloupe)
4. Substances that cause false-negative results for occult blood testing include the following:
a. Ascorbic acid (vitamin C) in excess of 250 mg/day
b. Vitamin C–enriched foods and juices
c. Iron supplements that contain vitamin C in excess of 250 mg
d. See Appendix J for other drugs.
5. Other factors affecting test results include the following:
a. Bleeding hemorrhoids may produce erroneous results; take samples from center of stool to avoid this error.
b. Collection of specimen during menstrual period
c. Hematuria (ie, blood in urine)
d. Some long-distance runners (23%) have positive outcomes for occult blood.
e. Toilet bowl cleansers may interfere with the chemical reaction of the test; remove bowl cleaners and flush twice
before proceeding with test.
Interventions
Pretest Patient Preparation
1. Explain the purpose, procedure, and interfering factors of the test as well as the need to follow appropriate stool
collection protocols for using special kit for fecal occult blood or a plastic container with a lid.
2. Recommend that the patient consume a high-residue diet, starting 72 hours before and continuing throughout the
collection period. Roughage in diet can increase test accuracy by helping to uncover silent lesions that bleed

intermittently. The diet may include the following:
a. Meats: only small amounts of chicken, turkey, and tuna
b. Vegetables: generous amounts of both raw and cooked vegetables, including lettuce, corn, spinach, carrots,
and celery; avoid vegetables with high peroxidase activity (see 3b above)
c. Fruits: plenty of fruits, especially prunes
d. Cereals: bran and bran-containing cereals
e. Moderate amounts of peanuts and popcorn daily. If any of the above foods are known to cause discomfort, the
patient should consult the physician.
3. Ensure that the patient receives no barium enemas 72 hours before or during testing.

Education Alert
Do not collect samples during or until 3 days after your menstrual period, or while you have bleeding hemorrhoids
or blood in your urine.
Do not consume the following medications, vitamins, and foods: for 7 days before and during the test period,
avoid aspirin or other NSAIDs; for 72 hours before and during the test period, avoid vitamin C in excess of 250
mg/d (from all sources, dietary and supplementary), red meat (eg, beef, lamb), including processed meats and
liver, and raw fruits and vegetables (especially melons, radishes, turnips, and horseradish).
Remove toilet bowl cleaners from toilet tank and flush twice before proceeding to defecate.
Collect samples from three consecutive bowel movements or three bowel movements closely spaced in time and
spread a small stool sample (minimum, 1 mL) on each of the three slides or card provided.
Protect card or slides from heat, light, and volatile chemicals (eg, iodine, bleach). Keep cover flap of slides closed
when not in use.
Posttest Patient Aftercare
1. Patient may resume normal diet after testing is complete.
2. Interpret occult blood test results and record findings. Counsel the patient regarding abnormal findings and monitor
as necessary. Advise that further testing (eg, barium enema, defecography) and follow-up may be required.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Clinical Alert
Blood in the stool is abnormal and should be reported and recorded.
Apt Test for Swallowed Blood
Dr. L. Apt developed the test for identifying the swallowed blood syndrome. The swallowed blood syndrome refers to
bloody stools usually passed on the second or third day of life. The blood may be swallowed during delivery or may be
from a fissure of the mother's nipple in breast-fed infants. This condition must be differentiated from GI hemorrhage of the
newborn. The test is based on the fact that the infant's blood contains largely fetal hemoglobin (Hb F), which is alkali
resistant. This blood can be differentiated from the mother's blood using laboratory methods.
The Apt test is used to differentiate swallowed blood syndrome from infant GI hemorrhage. The test can be done on
feces or vomitus. In the laboratory, the blood is dissolved and treated with NaOH for alkali denaturation. Fetal
hemoglobin is alkali resistant, and the solution of blood remains pink. Swallowed blood of maternal origin contains adult
hemoglobin, which is converted to brownish hematin when the alkali is added.
Reference Values
Normal Test result will indicate whether blood present in newborn feces or vomitus is of maternal or fetal origin.
Procedure
1. Collect a random stool specimen from a newborn infant; observe standard precautions.
2. The following are acceptable specimens:
a. Blood-stained diaper
b. Grossly bloody stool
c. Bloody vomitus or gastric aspiration
3. Place specimen or specimens in a biohazard bag and deliver to the laboratory as soon as possible. Refrigerate the
specimen or specimens if there is any delay.
Clinical Implications
1. Fetal hemoglobin, which is pink in color, is present in gastric hemorrhage of the newborn.
2. Adult hemoglobin, which is brownish in color, is present in swallowed blood syndrome in the infant.
Interfering Factors
1.
2.
3.
4.

The test is invalid with black, tarry stools because the blood has already been converted to hematin.
The test is invalid if there is insufficient blood present; grossly visible blood must be present in the specimen.
Vomitus with pH < 3.9 produces an invalid test result.
The presence of maternal thalassemia major produces a false-positive test result because of increased maternal
hemoglobin F.

Interventions

Pretest Patient Preparation
1. Advise parent or parents of the purpose of the test.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Review test results and counsel the parent or parents regarding test outcome, further testing, and possible
treatment for infant GI hemorrhage.
2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Mucus in Stool
The mucosa of the colon secretes mucus in response to parasympathetic stimulation. Recognizable mucus in a stool
specimen is abnormal and should be reported and recorded.
Reference Values
Normal Negative for mucus
Procedure Collect a random stool specimen. Observe and report findings of mucus.
Clinical Implications
1. Translucent gelatinous mucus clinging to the surface of formed stool occurs in the following conditions:
a. Spastic constipation
b. Mucous colitis
c. Emotionally disturbed patients
d. Excessive straining at stool
2. Bloody mucus clinging to the feces suggests the following conditions:
a. Neoplasm
b. Inflammation of the rectal canal
3. In villous adenoma of the colon, copious quantities of mucus may be passed (up to 3–4 L in 24 hours).
4. Mucus and diarrhea with white and red blood cells is associated with the following conditions:
a. Ulcerative colitis (Shigella)
b. Bacillary dysentery (Salmonella)
c. Ulcerating cancer of colon
d. Acute diverticulitis
e. Intestinal tuberculosis
f. Regional enteritis
g. Amebiasis
Interventions
Pretest Patient Preparation
1. Advise patient of purpose of observing for stool mucus.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
3. Ensure that the patient avoids laxatives and barium procedures for 1 week before test.
Posttest Patient Aftercare
1. Report and record presence, type, and amount of mucus.
2. Counsel patient appropriately. Monitor bowel habits. Explain that further testing and follow-up monitoring may be
necessary.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Stool pH
Stool pH is diet dependent and is based on bacterial fermentation in the small intestine. Carbohydrate fermentation
changes the pH to acid; protein breakdown changes the pH to alkaline.
Stool pH testing is done to evaluate carbohydrate and fat malabsorption and assess disaccharidase deficiency.
Breast-fed infants have slightly acid stool; bottle-fed infants have slightly alkaline stools.
Reference Values
Normal
1. Neutral to slightly acid or alkaline: pH 7.0–7.5 depending on diet
2. Newborns: pH 5.0–7.5
Procedure
1. Collect a fresh, random stool specimen in a plastic container with a tight-fitting lid (see p. 266).
2. Refrigerate specimen.
Clinical Implications

1. Increased pH (alkaline)
a. Secretory diarrhea without food intake
b. Colitis
c. Villous adenoma
d. Antibiotic use (impaired colonic fermentation)
2. Decreased pH (acid)
a. Carbohydrate malabsorption
b. Fat malabsorption
c. Disaccharidase deficiency (intestinal)
Interfering Factors
1. Barium procedures and laxatives affect test outcomes. They should be avoided for 1 week before stool sample
collection.
2. Specimens contaminated with urine will invalidate the test.
Interventions
Pretest Patient Preparation
1. Explain the purpose and procedure of the test, following general guidelines in Chapter 1 for safe, effective,
informed pretest care.
2. Advise patient that laxatives and barium procedures should be avoided for 1 week before stool sampling.
Posttest Patient Aftercare
1. Interpret pH outcome and record findings. If abnormal pH is found, assess dietary patterns and antibiotic use.
2. Monitor as appropriate for malabsorption syndrome.
3. Order a stool reducing substance test if disaccharidase deficiency is suspected (see Stool Reducing Substances
Test below).
4. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Stool Reducing Substances Test
Normally, sugars are rapidly absorbed in the upper small intestine. However, if this is not the case, they remain in the
intestine and cause osmotic diarrhea due to osmotic pressure of the unabsorbed sugar in the intestine, drawing fluid and
electrolytes into the gut. The unabsorbed sugars are measured as reducing substances. Reducing substances that can
be detected in the stool include glucose, fructose, lactose, galactose, and pentose. Carbohydrate malabsorption is a
major cause of watery diarrhea and electrolyte imbalance seen in patients with the short bowel syndrome. Idiopathic
lactase deficiency is common, occurring in 70% to 75% of Southern European Greeks and Italians, 70% of Black adults,
>90% of Asian adults, and 5% to 20% of Caucasian American adults.
The finding of elevated levels of reducing substances in the stool is abnormal and suggests carbohydrate malabsorption.
A presumptive diagnosis of disaccharide intolerance can be made with an elevated reducing substance level along with
an acid (ie, low) pH.
Reference Values
Normal
1. Normal: <0.25 g/dL (or <13.9 mmol/L) reducing substances in stool
2. Questionable: 0.25–0.50 g/dL (or 13.9–27.8 mmol/L) reducing substances in stool
Abnormal >0.5 g/dL (or >27.8 mmol/L)reducing substances in stool
Procedure Collect a fresh, random stool specimen and immediately deliver it to the laboratory (see p. 266).
Clinical Implications Elevated reducing substances in stool are found in the following conditions:
1.
2.
3.
4.

Disaccharidase deficiency (intestinal)
Short bowel syndrome
Idiopathic lactase deficiency, primary alactasia (enzyme deficiency leading to lactose intolerance)
Carbohydrate malabsorption abnormalities due to:
a. Sprue
b. Celiac disease
c. Viral gastroenteritis

Interfering Factors
1. Bacterial fermentation of sugars may give falsely low results if the stool is not tested immediately.
2. Newborns may normally have elevated results.
3. Drug may cause malabsorption (eg, neomycin, kanamycin, methotrexate).
Interventions
Pretest Patient Preparation
1. Explain the purpose of the test and interfering factors.

2. Follow guidelines in Chapter 1 regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes. Follow guidelines in Chapter 1 for safe, effective, informed posttest care .
2. If outcome is positive, further testing (lactose intolerance) and/or treatment (dietary therapy) may be necessary.
Leukocytes in Stool
Microscopic examination of the feces for the presence of white blood cells (leukocytes) is performed as a preliminary
procedure in determining the cause of diarrhea. Leukocytes are normally not present in stools and are a response to
infection or inflammation.
The presence or absence of fecal leukocytes can provide diagnostic information before the isolation of a bacterial
pathogen. Neutrophils (>3 neutrophils per high-power field) are seen in the feces in conditions that affect the intestinal
wall (eg, ulcerative colitis, invasive bacterial pathogen infection). Viruses and parasites usually do not cause neutrophils
in the stool. The greater the number of leukocytes, the greater the likelihood that an invasive pathogen is present.
Reference Values
Normal Negative for leukocytes
Procedure Collect a random stool specimen (see p. 266). Mucus or a liquid stool specimen can be used. A fresh
specimen is preferred, or it may be preserved in PVA.
Clinical Implications
1. Large amounts of leukocytes (primarily neutrophils) accompany the following conditions:
a. Chronic ulcerative colitis
b. Bacillary dysentery
c. Localized abscesses
d. Fistulas of the sigmoid rectum or anus
e. Shigellosis
f. Salmonellosis
g. Yersinia infection
h. Invasive Escherichia coli diarrhea
i. Campylobacter
2. Primarily mononuclear leukocytes appear in typhoid. Few leukocytes are sometimes seen in amebiasis.
3. Absence of leukocytes is associated with the following conditions:
a. Cholera
b. Nonspecific diarrhea (eg, drug or food induced)
c. Viral diarrhea
d. Amebic colitis (many red blood cells)
e. Noninvasive E. coli diarrhea
f. Toxigenic bacteria (eg, Staphylococcus, Clostridium)
g. Parasites (eg, Giardia, Entamoeba)
Interfering Factors Fecal leukocytes cannot be performed on formalin-preserved specimens.
Interventions
Pretest Patient Preparation
1. Explain the purpose of the test and the collection procedure. Follow guidelines in Chapter 1 for safe, effective,
informed pretest care.
2. Ensure that the patient avoids barium procedures and laxatives for 1 week before test.
3. Withhold antibiotic therapy until after collection.
Posttest Patient Aftercare
1. Interpret abnormal test results. Monitor for diarrhea. Counsel patient concerning the need for follow-up tests (stool
culture) and treatment (drugs, eg, antibiotics).
2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Collection and Transport of 24-, 48-, 72-, and 96-Hour Stool Specimens
This method is used to test for fat, porphyrins, urobilinogen, nitrogen, and electrolytes.
Special Instructions for Submitting Individual Specimens
1. Collect all stool specimens for 1 to 3 days. The entire stool should be collected. Some procedures may require 4
days.
2. Label specimens with day of test (eg, Day 1, Day 2, Day 3, Day 4), time of day collected, patient's name, and tests
ordered. It is important for calculations to disclose the number of days collected.
3. Submit individual specimens to the laboratory as soon as they are collected.
Special Instructions for Submitting Total Specimens
1. Obtain a 1-gallon container from the laboratory (a 1-gallon paint tin or covered plastic pail is preferred).

2. Save all stool and place in the container. Keep refrigerated or in a container with canned ice and replace ice as
needed.
3. Transfer the properly labeled container to the laboratory at the end of the collection period.
4. Record dates, duration of collection time period, tests to be performed, patient's name, and other vital information
on the collection receptacle.
Fat in Stool; Fecal Fat Stain
Fecal fat is the gold standard test for diagnosing steatorrhea (malabsorption). The three major causes of steatorrhea,
which is a pathologic increase in fecal fat, are impairment of intestinal absorption, deficiency of pancreatic digestive
enzymes, and deficiency of bile.
Specimens from patients suspected of having steatorrhea can be screened microscopically for the presence of excess
fecal fat. This procedure can also be used to monitor patients undergoing treatment for malabsorption disorders. In
general, there is good correlation between the qualitative and quantitative fecal fat procedures. Lipids included in the
microscopic examination of feces are neutral fats (triglycerides), fatty acid salts (soaps), fatty acids, and cholesterol. The
presence of these lipids can be observed microscopically by staining with Sudan III, Sudan IV, or oil red O dye. The
staining procedure consists of two parts: the neutral fat stain and the split fat stain for fatty acids.
Reference Values
Normal
1. Qualitative
a. Neutral fat: <50 fat globules per high-power field
b. Fatty acids: <100 fat globules per high-power field
2. Quantitative
a. Adult: 2–7 g/24 h (or 2–7 g/d) and <20% of total solids
b. Infant: <1.0 g/24 h (or <1.0 g/d) and breast fed 10%–40% of total solids; bottle fed 30%–50% of total solids
Procedure
1. Collect a 48- to 96-hour specimen for the quantitative test. A random specimen can be used for the qualitative test.
Each individual stool specimen is collected and identified with the name of the patient, time and date of collection,
and test to be performed. Also indicate the length (actual time frame) of the collection period. The specimen should
be sent immediately to the laboratory.
2. Follow the procedure for the collection of 24-, 48-, or 72-hour specimens.
Clinical Implications
1. Increases in fecal fat and fatty acids are associated with malabsorption syndrome caused by the following
conditions:
a. Celiac disease
b. Crohn's disease
c. Whipple's disease
d. Cystic fibrosis
e. Regional enteritis
f. Sprue
g. Atrophy of malnutrition
2. Increases in fecal fat and fatty acids are also found in the following conditions:
a. Enteritis and pancreatic diseases in which there is a lack of lipase (eg, chronic pancreatitis)
b. Surgical removal of a section of the intestine
3. Fecal fat test does not provide a diagnostic explanation for the presence of steatorrhea. It is not useful for
differentiating among pancreatic diseases.
a. D-Xylose absorption test may be ordered for the differential diagnosis of malabsorption.
Interfering Factors
1. Increased neutral fat may occur under the following nondisease conditions:
a. Use of rectal suppositories and/or oily creams applied to the perineum
b. Ingestion of castor oil, mineral oil
c. Ingestion of dietetic low-calorie mayonnaise, oily salad dressings
d. Ingestion of high-fiber diet (>100 g/24 h or >100 g/d)
e. Use of psyllium-based stool softeners (eg, Metamucil)
2. Use of barium and bismuth interfere with test results.
3. Urine contaminates the specimen.
4. A random stool specimen is not an acceptable sample for the quantitative fat test.
Interventions
Pretest Patient Preparation
1. Explain the purpose of the test, interfering factors, and the procedure for the collection of specimens. Follow
guidelines in Chapter 1 concerning diverse patient needs and safe, effective, informed pretest care.
2. For a 72- to 96-hour stool collection, ensure the patient has a diet containing 100–150 g of fat, 100 g of protein, and
180 g of carbohydrate for 6 days before and during the test.
3. Do not allow patient to have laxatives for 3 days before the test.

4. Follow the procedure for the collection of 72-hour stool specimens.
Posttest Patient Aftercare
1. Resume normal diet.
2. Record appearance, color, and odor of all stools in persons suspected of having steatorrhea. The typical stool in
patients with this condition is foamy, greasy, soft, pasty, and foul smelling.
3. Counsel patient concerning test outcome and possible need for further testing (eg, colonoscopy) and treatment (eg,
elimination of certain foods from the diet).
4. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Meat Fibers in Stool; Stool Muscle Fiber
The presence of undigested meat fibers (ie, muscle fibers) in stool implies impaired intraluminal digestion. There is
positive correlation between the presence of meat or muscle fibers and the presence of fat excreted in the stool.
Reference Values
Normal Negative (no undigested meat fibers present in the normal stool)
Procedure
1. Ensure that the patient eats 4 to 6 ounces of red meat for 24 to 72 hours before testing.
2. Collect a random specimen (see p. 266). Specimens obtained with warm saline enema or Fleet Phospho-Soda are
acceptable.
3. Record method and type of stool procurement.
Clinical Implications Increased amounts of meat fibers are found in the following conditions:
1. Malabsorption syndromes caused by biliary obstruction
2. Pancreatic exocrine dysfunction (cystic fibrosis)
3. Gastrocolic fistula
Interfering Factors
1. Specimens should not be obtained with mineral oil, bismuth, or magnesium compounds.
2. Barium procedures and laxatives should be avoided for 1 week before collection.
Interventions
Pretest Patient Preparation
1. Explain the purpose of the test and interfering factors.
2. Ensure that the patient eats a high-meat diet for 72 hours before test.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Resume normal diet.
2. Interpret test outcomes.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Urobilinogen in Stool
Increased destruction of red blood cells, as in hemolytic anemia, increases the amount of urobilinogen excreted. Liver
disease, in general, reduces the flow of bilirubin to the intestine and thereby decreases the fecal excretion of
urobilinogen. In addition, complete obstruction of the bile duct reduces urobilinogen to very low levels.
This test investigates hemolytic diseases and hepatic obstructive conditions. Determination of stool urobilinogen is an
estimation of the total excretion of bile pigments, which are the breakdown products of hemoglobin.
Reference Values
Normal
1. 50–300 mg/24 h or 100–400 Ehrlich units/100 g
2. Newborns–6 months: negative
Procedure
1. Collect a 48-hour specimen.
2. Protect the specimen from light. Send to the laboratory as soon as possible.
Clinical Implications
1. Increased values are associated with hemolytic anemias.
2. Decreased values are associated with the following conditions:

a.
b.
c.
d.

Complete biliary obstruction (clay-colored feces result)
Severe liver disease (eg, infectious hepatitis)
Oral antibiotic therapy that alters intestinal bacterial flora
Aplastic anemia, which results in decreased hemoglobin turnover

Interfering Factors See Appendix J for drugs that affect test outcomes.
Interventions
Pretest Patient Preparation
1.
2.
3.
4.

Explain purpose of test.
Ensure that the patient does not receive oral antibiotic therapy for 1 week before test.
Ensure that the patient avoids laxatives and barium procedure 1 week before test.
Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Aftercare
1. Interpret test outcomes. Counsel patient appropriately regarding further testing. Monitor patient for liver disease,
biliary obstruction, and diarrhea.
2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Trypsin in Stool: Fecal Chymotrypsin
Trypsin is a proteolytic enzyme formed in the small intestine. In older children and adults, trypsin is destroyed by bacteria
in the GI tract. Inadequate trypsin secretion can lead to malabsorption and abdominal discomfort. Chymotrypsin, an
intestinal proteolytic enzyme secreted by the pancreas, can be used to assess pancreatic function. Fecal chymotrypsin is
a more reliable measurement of pancreatic function than trypsin.

Procedural Alert
This test will probably be replaced by immunoassays. It is an unreliable test in older children and adults.
Reference Values
Normal Trypsin, 20–950 U/g or 20–950 µg/g stool Chymotrypsin, 74–1200 µg/g or 74–1200 mg/kg stool
Procedure
1. Collect random specimens and send to the laboratory. Three separate, fresh stools are usually collected.
2. Ensure that the specimen is taken to the laboratory and tested within 2 hours.
3. Give a cathartic before obtaining a specimen from older children (saline or Fleet only).
Clinical Implications Decreased amounts of trypsin occur in the following conditions:
1. Pancreatic deficiency syndromes (0–33 U/g or 0–33 µg/g stool)
2. Cystic fibrosis (sweat chloride test is diagnostic) (<20 U/g or <20 µg/g stool)
Interfering Factors
1. No trypsin activity is detectable in constipated stools owing to prolonged exposure to intestinal bacteria, which
inactivates trypsin.
2. Barium and laxatives used less than 1 week before test affect results.
3. In adults, the test is unreliable owing to trypsin inactivation by intestinal flora.
4. Bacterial proteases may produce positive reactions when no trypsin is present.
Interventions
Pretest Patient Preparation
1. Explain purpose of test and interfering factors.
2. Ensure that the patient avoids barium procedures and laxatives for 1 week before stool collection.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret abnormal test results and counsel patient concerning possible need for follow-up testing (eg, sweat
testing) and treatment (enzymes).
2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Clinical Alert
1. Diagnosis of pancreatic insufficiency should not be made until three specimens exhibit no trypsin activity.
2. Bacterial protease may produce positive reactions when no trypsin is present; therefore, both positive and
negative reactions should be carefully interpreted.
Stool Electrolytes: Sodium, Chloride, Potassium, and Osmolality

Normal colon function involves absorption of fluid and electrolytes.
Stool electrolyte tests are used to assess electrolyte imbalance in patients with diarrhea. Stool electrolytes must be
evaluated along with the serum and urine electrolytes as well as clinical findings in the patient. Stool osmolality is used in
conjunction with blood serum osmolality to calculate the osmotic gap and to diagnose intestinal disaccharide deficiency.
Reference Values
Normal
1.
2.
3.
4.
5.

Sodium: 5.8–9.8 mEq/24 h or 5.8–9.8 mmol/d
Chloride: 2.5–3.9 mEq/24 h or 2.5–3.9 mmol/d
Potassium: 15.7–20.7 mEq/24 h or 15.7–20.7 mmol/d
Osmolality: 275–295 mOsm/kg
Osmotic gap: measured osmolality (2 [NA + K])

Reference values vary from laboratory to laboratory. Check with your laboratory for normal values.
Procedure
1. Collect a random or 24-hour liquid stool specimen.
2. Keep the specimen covered and refrigerated.
Clinical Implications
1. Electrolyte abnormalities occur in the following conditions:
a. Idiopathic proctocolitis: increased sodium (Na) and chloride (Cl); normal potassium (K)
b. Ileostomy: increased sodium (Na) and chloride (Cl), low potassium (K)
c. Cholera: increased sodium (Na) and chloride (Cl)
2. Chloride is greatly increased in stool in the following conditions:
a. Congenital chloride diarrhea
b. Acquired chloride diarrhea or secondary chloride diarrhea
c. Idiopathic proctocolitis
d. Cholera
3. Stool osmolality 500 mg/dL per day is suspicious for factitious disorders (eg, laxative abuse, ingestion of rat
poison). Higher levels indicate high amounts of stool reducing substances. The osmotic gap is increased in osmotic
diarrhea caused by the following conditions:
a. Saline laxatives
b. Sodium or magnesium citrate
c. Carbohydrates (lactulose or sorbitol candy)
Interfering Factors
1. Formed stools invalidate the results. Stools must be liquid for electrolyte tests.
2. The stool cannot be contaminated with urine.
3. Surreptitious addition of water to the stool specimen considerably lowers the osmolality. Stool osmolality must be
less than 240 mOsm/kg (or <240 mmol/kg H 2O) to calculate the osmotic gap.
4. See Appendix J for drugs that cause increased values.
Interventions
Pretest Patient Preparation
1. Explain purpose of test, procedure for stool collection, and interfering factors.
2. Ensure the patient avoids barium procedures and laxatives for 1 week before collection of specimen.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret abnormal test outcomes. Monitor diarrhea episodes and record findings. Assess patient for electrolyte
imbalances and counsel regarding further testing and treatment.
2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
BIBLIOGRAPHY
Bakerman S: ABCs of Interpretive Laboratory Data, 3rd ed. Greenville, NC, Interpretive Laboratory Data Inc., 1993
Bauer TM, et al: Derivation and validation of guidelines for stool cultures for enteropathogenic bacteria other than Clostridium difficile in
hospitalized adults. JAMA, 285:313–319, 2001
Bennett JC, Goldman L, (eds): Cecil Textbook of Medicine, 21st ed. Philadelphia, WB Saunders, 2000
Henry JB (ed): Clinical Diagnosis and Management by Laboratory Methods, 20th ed. Philadelphia, WB Saunders, 2001
Leaville DE (ed): Medical Laboratories Interpretive Handbook. Rochester, MN, Mayo Medical Laboratories, 2001
Lehman CA (ed): Saunders Manual of Clinical Laboratory Science. Philadelphia, WB Saunders, 1998

Levin B, Hess K, Johnson C: Screening for colorectal cancer. A comparison of 3 fecal occult blood tests. Arch Intern Med 157:970, 1997
Mylonakis E, Ryan ET, Calderwood SB: Clostridium difficile-associated diarrhea. Arch Intern Med, 161:525–533, 2001
Novak RW: Identifying leukocytes in fecal specimens. Lab Med 27:433, 1996
Sentongo TA, Rutstein RM, Stettler N, Stallings VA, Rudy B, Mulberg AE: Association between steatorrhea, growth, and immunologic status in
children with perinatally acquired HIV infection. Arch Pediatr Adolesc Med, 155:149–153, 2001
Speicher CE: The Right Test, A Physician's Guide to Laboratory Medicine, 3rd ed. Philadelphia, WB Saunders, 1998
Strasinger S, DiLorenzo MS: Urinalysis and Body Fluids, 4th ed. Philadelphia, FA Davis, 2001
Tietz, N: Clinical Guide to Laboratory Tests, 3rd ed. Philadelphia, WB Saunders, 1995
Wallach J: Interpretation of Laboratory Tests, Synopsis of Laboratory Medicine, 7th ed. Boston, Little, Brown & Co., 2000
Young DS: Effects of Drugs in Clinical Laboratory Tests, 5th ed. Washington, DC, AACC Press, 1999
Young DS, Friedman RB: Effects of Disease on Clinical Laboratory Tests, 4th ed. Washington, DC, AACC Press, 2001

5 Cerebrospinal Fluid Studies
A Manual of Laboratory and Diagnostic Tests

5
Cerebrospinal Fluid Studies
OVERVIEW OF CEREBROSPINAL FLUID (CSF)
Description, Formation, and Composition of CSF
Explanation of Tests
Clinical Alert
Clinical Alert
CEREBROSPINAL FLUID TESTS
Lumbar Puncture (Spinal Tap)
CSF Pressure
CSF Color and Appearance
CSF Microscopic Examination of Cells; Total Cell Count; Differential Cell Count
CSF Glucose
CSF Glutamine
CSF Lactic Acid
CSF Lactate Dehydrogenase (LD/LDH); CSF Lactate Dehydrogenase (LDH) Isoenzymes
CSF Total Protein
CSF Albumin and Immunoglobulin G (IgG)
CSF Protein Electrophoresis; Oligoclonal Bands; Multiple Sclerosis Panel
CSF Syphilis Serology
BIBLIOGRAPHY

OVERVIEW OF CEREBROSPINAL FLUID (CSF)
Description, Formation, and Composition of CSF
Cerebrospinal fluid (CSF) is a clear, colorless fluid formed within the cavities (ie, ventricles) of the brain. The choroid
plexus produces about 70% of the CSF by ultrafiltration and secretion. The ependymal lining of the ventricles and
cerebral subarachnoid space produce the remainder of the CSF total volume. Approximately 500 mL of CSF fluid is
formed per day, although only 90 to 150 mL is present in the system at any one time. Reabsorption of CSF occurs at the
arachnoid villi.
CSF circulates slowly from the ventricular system into the space surrounding the brain and spinal cord and serves as a
hydraulic shock absorber, diffusing external forces to the skull that might otherwise cause severe injury. The CSF also
helps to regulate intracranial pressure (ICP), supply nutrients to the nervous tissues, and remove waste products. The
chemical composition of CSF does not resemble an ultrafiltrate of plasma. Certain chemicals in the CSF are regulated by
specific transport systems (eg, K +, Ca 2+, Mg 2+ ), whereas other substances (eg, glucose, urea, creatinine) diffuse
freely. Proteins enter the CSF by passive diffusion at a rate dependent on the plasma-to-CSF concentration gradient.
The term blood-brain barrier is used to represent the control and filtration of blood plasma components (eg, restriction of
protein diffusion from blood into brain tissue) to the CSF and then to the brain capillaries. The ratio of increased albumin
in CSF to blood serum is always caused by blood-brain barrier dysfunction because albumin is found extensively in
blood. A decreased CSF flow rate is due to decreased production or restriction or blockage of flow.
Most CSF constituents are present in the same or lower concentrations as in the blood plasma, except for chloride
concentrations, which are usually higher. Disease, however, can cause elements ordinarily restrained by the blood-brain
barrier to enter the spinal fluid. Erythrocytes and leukocytes can enter the CSF from the rupture of blood vessels or from
meningeal reaction to irritation. Bilirubin can be found in the spinal fluid after intracranial hemorrhage. In such cases, the
arachnoid granulations and the nerve root sheaths will reabsorb the bloody fluid. Normal CSF pressure will consequently
be maintained by the reabsorption of CSF in amounts equal to its production. Blockage causes an increase in the amount
of CSF, resulting in hydrocephalus in infants or increased ICP in adults. Of the many factors that regulate the level of
CSF pressure, venous pressure is the most important because the reabsorbed fluid ultimately drains into the venous
system.
Despite the continuous production (˜0.3 mL/min) and reabsorption of CSF and the exchange of substances between the
CSF and the blood plasma, considerable pooling occurs in the lumbar sac. The lumbar sac, located at L4 to L5, is the
usual site used for puncture to obtain CSF specimens because damage to the nervous system is less likely to occur in
this area. In infants, the spinal cord is situated more caudally than in adults (L3–L4 until 9 months of age, when the cord
ascends to L1–L2); therefore; a low lumbar puncture should be made in these patients ( Table 5.1).

Table 5.1 Normal CSF Values
Volume
Appearance
Pressure
Total cell count

Adult: 90–150 mL; child: 60–100 mL
Crystal clear, colorless
Adults: 90–180 mm H 2O; child: 10–100 mm H 2 O
Essentially free cells

WBCs
Differential
Lymphocytes
Monocytes
Polys
RBCs (has limited diagnostic value)
Specific gravity
Clinical Tests
Glucose
Protein
Lumbar

Adults

Newborn (0–14
d)

0–5 cells

0–30 cells

40%–80%
15%–45%
0%–6%

5%–35%
50%–90%
0%–8%

1.006–1.008
40–70 mg/dL (2.2–3.9 mmol/L)

Adults: 15–45 mg/dL (150–450 mg/L)
Neonates: 15–100 mg/dL (150–1000 mg/L)
Elderly (>60 y): 15–60 mg/dL
Cisternal
15–25 mg/dL (150–250 mg/L)
Ventricular
5–15 mg/dL (50–150 mg/L)
Lactic acid (lactate)
10–24 mg/dL (1.11–2.66 mmol/L)
Glutamine
5–20 mg/dL (0.34–1.37 mmol/L)
Albumin
10–35 mg/dL (1.52–5.32 µmol/L)
Urea nitrogen
6–16 mg/dL (2.14–5.71 mmol/L)
Creatinine
0.5–1.2 mg/dL (44–106 µmol/L)
Uric acid
0.5–4.5 mg/dL (29.7–268 µmol/L)
Bilirubin
0 (none)
Phosphorous
1.2–2.0 mg/dL (387–646 µmol/L)
Ammonia
10–35 µg/dL (5.87–20.5 µmol/L)
Lactate dehydrogenase (LDH) (10% of serum level) Adult: 0–40 U/L (0–0.67 µkat/L)
Electrolytes and pH
pH
Lumbar
7.28–7.32
Cisternal
7.32–7.34
Chloride
115–130 mEq/L (mmol/L)
Sodium
135–160 mEq/L (mmol/L)
Potassium
2.6–3.0 mEq/L (mmol/L)
CO 2 content
20–25 mEq/L (mmol/L)
PCO 2
44–50 mm Hg (5.8–6.6 kPa)
PO 2
40–44 mm Hg (5.3–5.8 kPa)
Calcium
2.0–2.8 mEq/L
Magnesium
2.4–3.0 mEq/L
Osmolality
280–300 mOsm/kg (280–300 mmol/kg)
Serology and Microbiology
VDRL
Negative
Bacteria
None present
Viruses
None present
Antibody index
>1.5 indicates chronic inflammatory process
<0.4 probably not acute inflammatory process
Be sure to include patient's age because it is needed to evaluate borderline values.

60–80 mg/dL

1.0–1.4 mmol/L
1.2–1.5 mmol/L

Explanation of Tests
Cerebrospinal fluid, obtained by lumbar/intrathecal puncture, is the main diagnostic tool for neurologic disorders. A
lumbar/intrathecal puncture is done for the following reasons:
1. To examine the spinal fluid for diagnosis of four major disease categories:
a. Meningitis
b. Subarachnoid hemorrhage
c. CNS malignancy (meningeal carcinoma, tumor metastasis)
d. Autoimmune disease and multiple sclerosis
2. To determine level of CSF pressure, to document impaired CSF flow, or to lower pressure by removing volume of
fluid. (Fluid removal should be done with caution.)
3. To identify disease-related immunoglobulin patterns (IgG, IgA, and IgM referenced to albumin) in
neurotuberculosis, neuroborreliosis (after a tick bite), or opportunistic infections.
4. To introduce anesthetics, drugs, or contrast media used for radiographic studies and nuclear scans into the spinal
cord.
5. Confirm the identity of pathogens involved in acute inflammatory or chronic inflammatory disorders (eg, multiple
sclerosis and blood-brain barrier dysfunction).
6. Identify extent of brain infarction/stroke.

7. Formulate antibody index (AI) of the IgG class for polyspecific immune response in CNS. Examples: measles,
rubella, and zoster (MRZ) antibodies to viruses in multiple sclerosis (MS); HSV antibodies in MS; toxoplasma
antibodies in MS; and autoantibodies to dsDNA (double-stranded deoxyribonucleic acid).
8. Identify brain-derived proteins, such as neuron-specific enolase present after brain trauma.
See Figure 5.1 for an example of a CSF analysis report.

FIGURE 5.1 Cerebrospinal fluid analysis report. Source: Regeniter A, Steiger JU, Scholer A, Huber PR, Siede WH:
Windows to the ward: Graphically oriented report forms. Presentation of complex, interrelated laboratory data for
electrophoresis/immunofixation, cerebrospinal fluid, and urinary protein profiles. Clinical Chemistry, 49:1, 41–50, 2003.

Clinical Alert
The MRZ reaction occurs in MS, lupus erythematosus, Sjögren syndrome, or Wegener granulomatosis.
Certain observations are made each time lumbar puncture is performed:
1. CSF pressure is measured.
2. General appearance, consistency, and tendency of the CSF to clot are noted.
3. CSF cell count is performed to distinguish types of cells present; this must be done within 2 hours of obtaining the
CSF sample.
4. CSF protein and glucose concentrations are determined.
5. Other clinical serologic and bacteriologic tests are done when the patient's condition warrants (eg, culture for
aerobes and anaerobes or tuberculosis).
6. Tumor markers may be present in CSF; these tests are useful as supplements to CSF cytology analysis ( Table
5.2).
Table 5.2 Tumor Markers in CSF
Determination

Used in Diagnosis of

Normal Values *

Alpha-fetoprotein
(AFP)
Beta-Glucuronidase

CNS dysgerminomas and meningeal carcinomas

<1.5 mg/mL (<1.5
µg/L)
<49 mU/L (<0.82
nKat/L) normal; 47–70
mU/L (0.78–1.17
nKat/L), suspicious
>70 mU/L (>1.17
nKat/L) abnormal
<0.6 mg/mL (<0.6
µg/L)

Possible meningeal adenocarcinoma

Acute myeloblastic leukemia
Carcinoembryonic
antigen (CEA)

Meningeal carcinomatosis; intradural or extradural, or brain
parenchymal metastasis from adenocarcinoma; although the
assay appears to be specific for adenocarcinoma and
squamous cell carcinoma, increased CEA values in CSF are
not seen in all such tumors of the brain
Adjunct in determining CNS dysgerminomas and meningeal
carcinomatosis
CNS tumors, especially myoclonal and monocytic leukemia

Human chorionic
gonadotropin (HCG)
Lysozyme
(muramidase)
Note: The value of tumor markers in CSF for routine clinical diagnosis has not been
established.
*Normal values vary greatly; check with your reference laboratory.

<0.21 U/L (<1.5 IU/L)
4–13 µg/mL

Clinical Alert
1. Blood levels for specific substances should always be measured simultaneously with CSF determinations for
meaningful interpretation of results.
2. Before lumbar puncture, check eyegrounds for evidence of papilledema, because its presence may signal
potential problems or complications of lumbar puncture.
3. A mass lesion should be precluded by CT scan before lumbar puncture, because this can lead to brain stem
herniation.
4. However, if increased pressure is found while performing the lumbar puncture, it should not be necessary to stop
the procedure unless neurologic signs are present.

CEREBROSPINAL FLUID TESTS
Lumbar Puncture (Spinal Tap)
Procedure
1. Place the patient in a side-lying position with the head flexed onto the chest and knees drawn up to, but not
compressing, the abdomen to “bow” the back. This position helps to increase the space between the lower lumbar
vertebrae so that the spinal needle can be inserted more easily between the spinal processes. However, a sitting
position with the head flexed to the chest can be used. The patient is helped to relax and instructed to breathe
slowly and deeply with his or her mouth open.
2. Select the puncture site, usually between L4 and L5 or lower. There is a small bony landmark at the L5-S1
interspace known as the “surgeon's delight” that helps to locate the puncture site. The site is thoroughly cleansed
with an antiseptic solution, and the surrounding area is draped with sterile towels in such a way that the drapes do
not obscure important landmarks ( Fig. 5.2).

FIGURE 5.2 Spinal tap technique. The patient lies on his side with knees flexed and back arched to separate the
lumbar vertebrae. The patient is surgically draped and an area overlying the lumbar spine is disinfected ( A). The
space between lumbar vertebrae L 4 and L 5 is palpated with sterilely gloved forefinger ( B) and the spinal needle is
carefully directed between the spinous processes, through the infraspinous ligaments into the spinal canal ( C).
3. Inject a local anesthetic slowly into the dermis around the intended puncture site.
4. Insert a spinal needle with stylet into the midline between the spines of the lumbar space and slowly advance until it
enters the subarachnoid space. The patient may feel the entry as a “pop” of the needle through the dura mater.
Once this happens, the patient can be helped to straighten his or her legs slowly to relieve abdominal compression.
5. Remove the stylet with the needle remaining in the subarachnoid space, and attach a pressure manometer to the
needle to record the opening CSF pressure.
6. Remove a specimen consisting of up to 20 mL CSF. Take up to four samples of 2 to 3 mL each, place in separate
sterile vials, and label sequentially. Tube 1 is used for chemistry and serology; tube 2 is used for microbiology
studies; tube 3 is used for hematology cell counts; and tube 4 is used for special studies such as cryptococcal
antigens, syphilis testing (Venereal Disease Research Laboratory [VDRL]), protein electrophoresis, and other
immunologic studies. A closing pressure reading may be taken before the needle is withdrawn. In cases of
increased intracranial pressure (ICP), no more than 2 mL is withdrawn because of the risk that the brain stem may
shift.
7. Apply a small sterile dressing to the puncture site.
8. Label tubes correctly with the proper sequential number (1, 2, 3, or 4), the patient's name, and the date of
collection. Specimens of CSF must be immediately delivered to the laboratory, where they should be given to
laboratory personnel with specific instructions regarding the testing. CSF samples should never be placed in the
refrigerator because refrigeration alters the results of bacteriologic and fungal studies. Analysis should be started
immediately. If viral studies are to be done, a portion of the specimen should be frozen.
9. Record procedure start and completion times, patient's status, CSF appearance, and CSF pressure readings.

Procedural Alert
1. If the opening pressure is >200 mm H 2 O in a relaxed patient, no more than 2 mL of CSF should be withdrawn.
2. If the initial pressure is normal, the Queckenstedt's test may be done. (This test is not done if a central nervous
system [CNS] tumor is suspected.) In this test, pressure is placed on both jugular veins to occlude them
temporarily and to produce an acute rise in CSF pressure. Normally, pressure rapidly returns to average levels
after jugular vein occlusion is removed. Total or partial spinal fluid blockage is diagnosed if the lumbar pressure
fails to rise when both jugular veins are compressed or if the pressure requires >20 seconds to fall after
compression is released.
Interventions
Pretest Patient Preparation

1. Explain the purpose, benefits, and risks of lumbar puncture and explain tests to be performed on the CSF
specimen; present a step-by-step description of the actual procedure. Emphasize the need for patient cooperation.
Assess for contraindications or impediments such as arthritis. Sedation or analgesia may be used.
2. Help the patient to relax by having him or her breathe slowly and deeply. The patient must refrain from breath
holding, straining, moving, and talking during the procedure.
3. Follow guidelines in Chapter 1 regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have the patient lie prone (flat or horizontal, or on the abdomen) for approximately 4 to 8 hours. Turning from side
to side is permitted as long as the body is kept in a horizontal position.
2. Women may have difficulty voiding in this position. The use of a fracture bedpan may help.
3. Fluids are encouraged to help prevent or relieve headache, which is a possible result of lumbar puncture.
4. Interpret test outcomes. Assess and monitor for abnormal outcomes and complications such as paralysis (or
progression of paralysis, as with spinal tumor), hematoma, meningitis, asphyxiation of infants due to tracheal
obstruction from pushing the head forward, and infection. Institute infection control precautions if test outcomes
reveal an infectious process.
5. Observe for neurologic changes such as altered level of consciousness, change of pupils, change in temperature,
increased blood pressure, irritability, and numbness and tingling sensations, especially in the lower extremities.
6. If headache occurs, administer analgesics as ordered and encourage a longer period of prone bed rest. If
headache persists, a “blood patch” may need to be done, in which a small amount of the patient's own blood is
introduced into the spinal canal at the same level that the canal was previously entered. For reasons not totally
understood, this blood patch very effectively stops spinal headaches within a very short period.
7. Check the puncture site for leakage.
8. Document the procedure completion and any problems encountered or complaints voiced by the patient.
9. Follow guidelines in Chapter 1 regarding safe, effective, informed posttest care.

Clinical Alert
1. Extreme caution should be used when performing lumbar puncture:
a. If ICP is elevated, especially in the presence of papilledema or split cranial sutures. However, with some
cases of increased ICP, such as with a coma, intracranial bleeding, or suspected meningitis, the need to
establish a diagnosis is absolutely essential and outweighs the risks of the procedure.
b. A relative contraindication would be ICP from a suspected mass lesion. To reduce the risk for brain herniation,
a less invasive procedure such as a CT scan or MRI should be done.
2. Contraindications to lumbar puncture include the following conditions:
a. Suspected epidural infection
b. Infection or severe dermatologic disease in the lumbar area, which may be introduced into the spinal canal
c. Severe psychiatric or neurotic problems
d. Chronic back pain
e. Anatomic malformations, scarring in puncture site areas, or previous spinal surgery at the site
3. If there is CSF leakage at the puncture site, notify the physician immediately and document findings.
4. Follow standard precautions (see Appendix A) when handling CSF specimens.
CSF Pressure
The CSF pressure is directly related to pressure in the jugular and vertebral veins that connect with the intracranial dural
sinuses and the spinal dura. In conditions such as congestive heart failure or obstruction of the superior vena cava, CSF
pressure is increased, whereas in circulatory collapse, CSF pressure is decreased.
Pressure measurement is done to detect impairment of CSF flow or to lower the CSF pressure by removing a small
volume of CSF fluid. Provided initial pressure is not elevated and there is no marked fall in the pressure as fluid is
removed, 10 to 20 mL of CSF may be removed without danger to the patient. Elevation of the opening CSF pressure may
be the only abnormality found in patients with cryptococcal meningitis and pseudotumor cerebri. Repeated lumbar
punctures are performed for ICP elevation in cryptococcal meningitis to decrease the CSF pressure.
Reference Values
Normal Adult: 90–180 mm H 2O in the lateral recumbent position. (This value is position dependent and will change with
a horizontal or sitting position.) Child (<8 years of age): 10–100 mm H 2O
Procedure
1. Measure the CSF pressure before any fluid is withdrawn.
2. Take up to four samples of 2 to 3 mL each, place in separate sterile vials, and label sequentially. Tube 1 is used for
chemistry and serology; tube 2 is used for microbiology studies; tube 3 is used for hematology cell counts; and tube
4 is used for special studies.
Clinical Implications
1. Increases in CSF pressure can be a significant finding in the following conditions:
a. Intracranial tumors; abscess; lesions
b. Meningitis (bacterial, fungal, viral, or syphilitic)
c. Hypoosmolality as a result of hemodialysis
d. Congestive heart failure

e. Superior vena cava syndrome
f. Subarachnoid hemorrhage
g. Cerebral edema
h. Thrombosis of venous sinuses
i. Conditions inhibiting CSF absorption
2. Decreases in pressure can be a significant finding in the following conditions:
a. Circulatory collapse
b. Severe dehydration
c. Hyperosmolality
d. Leakage of spinal fluid
e. Spinal-subarachnoid block
3. Significant variations between opening and closing CSF pressure can be found in the following conditions:
a. Tumors or spinal blockage above the puncture site when there is a large pressure drop (no further fluid should
be withdrawn)
b. Hydrocephalus when there is a small pressure drop that is indicative of a large CSF pool
Interfering Factors
1. Slight elevations of CSF pressure may occur in an anxious patient who holds his or her breath or tenses his or her
muscles.
2. If the patient's knees are flexed too firmly against the abdomen, venous compression will cause an elevation in CSF
pressure. This can occur in patients of normal weight and in those who are obese.
Interventions
Pretest Patient Preparation
1. See page 296 for care before lumbar puncture.
2. Follow guidelines in Chapter 1 regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret abnormal pressure levels and monitor and intervene appropriately to prevent complications.
2. See page 296 for care after lumbar puncture .
3. Follow guidelines in Chapter 1 regarding safe, effective, informed posttest care.
CSF Color and Appearance
Normal CSF is crystal clear, with the appearance and viscosity of water. Abnormal CSF may appear hazy, cloudy, smoky,
or bloody. Clotting of CSF is abnormal and indicates increased protein or fibrinogen levels.
The initial appearance of CSF can provide various types of diagnostic information. Inflammatory diseases, hemorrhage,
tumors, and trauma produce elevated cell counts and corresponding changes in appearance.
Reference Values
Normal Clear and colorless
Procedure Compare the CSF with a test tube of distilled water held against a white background. If there is no turbidity,
newsprint can be read through normal CSF in the tube.
Clinical Implications
1. Abnormal appearance ( Table 5.3)—causes and indications:
Table 5.3 Color Changes in CSF Suggestive of Disease States
Appearance

Condition

Opalescent, slightly yellow, with delicate clot
Opalescent to purulent, slightly yellow, with coarse
clot
Slightly yellow; may be clear or opalescent, with
delicate clot
Bloody, purulent, may be turbid
Generally clear, but may be xanthochromic
Xanthochromic
Viscous

Tuberculous meningitis
Acute pyogenic meningitis
Acute anterior poliomyelitis
Primary amebic meningoencephalitis
Tumor of brain or cord
Toxoplasmosis
Metastatic colon cancer, severe meningeal infection,
cryptococcus, injury

a. Blood. The blood is evenly mixed in all three tubes in subarachnoid and cerebral hemorrhage. Table 5.4
describes differentiation of bloody spinal tap from cerebral hemorrhage. Clear CSF fluid does not rule out
intracranial hemorrhage.
Table 5.4 Differentiation of Bloody CSF Caused by Subarachnoid Hemorrhage Versus Traumatic Lumbar
Puncture
CSF Findings

Subarachnoid Hemorrhage

Traumatic Lumbar Puncture *

CSF Pressure
Blood in tubes for collecting CSF
CSF clotting
Xanthochromia
Immediate repeat of lumbar puncture
at higher level

Often increased
Mixture with blood is uniform in all
tubes
Does not clot
Present if >8–12 h since cerebral
hemorrhage
CSF same as initial puncture

Normal
Tubes 1 and 2 more bloody
than tube 3 or 4
Often clots
Absent unless patient is
jaundiced
CSF clear (if atraumatic)

*CSF with RBCs >6000 per mm 3 appears grossly bloody

b. Turbidity is graded from 1+ (slightly cloudy) to 4+ (very cloudy) and may be caused by the following conditions:
1. Leukocytes (pleocytosis)
2. Erythrocytes
3. Microorganisms such as fungi and amebae
4. Protein
5. Epidural fat aspirated (pale pink to dark yellow)
6. Contrast media
c. Xanthochromia (pale pink to dark yellow) can be caused by the following conditions:
1. Oxyhemoglobin from lysed red blood cells (RBCs) present in CSF before lumbar puncture
2. Methemoglobin
3. Bilirubin (>6 mg/dL or >103 µmol/L)
4. Increased protein (>150 mg/dL or >1500 mg/L)
5. Melanin (meningeal melanocarcinoma)
6. Carotene (systemic carotenemia)
7. Prior bleeding within 2–36 hours (eg, traumatic puncture >72 hours before)
d. Yellow color (bilirubin >10 mg/dL or >171 µmol/L) due to a prior hemorrhage (10 hour to 4 weeks before)

Clinical Alert
1. Spinal fluid should be cultured for bacteria, fungi, and tuberculosis. In children, Haemophilus influenzae type B is
the most common cause of bacterial meningitis; in adults, the most common bacterial pathogens for meningitis
are meningococci and pneumococci.
2. Spinal fluid with any degree of cloudiness should be treated with extreme care because this could be an
indication of contagious disease.
Interfering Factors
1. CSF can look xanthochromic from contamination with methylate used to disinfect the skin.
2. If the blood in the specimen is due to a traumatic spinal tap, the CSF in the third tube should be clearer than that in
tube 1 or 2; a traumatic tap makes interpretation of results very difficult to impossible.
Interventions
Pretest Patient Preparation
1. Observations of color and appearance of CSF are always noted.
2. See page 296 for care before lumbar puncture.
Posttest Patient Aftercare
1. Recognize abnormal color and presence of turbidity and monitor patient appropriately.
2. See page 296 for care after lumbar puncture .
CSF Microscopic Examination of Cells; Total Cell Count; Differential Cell Count
Normal CSF contains a small number of lymphocytes and monocytes in a ratio of approximately 70:30 in adults. A higher
proportion of monocytes is present in young children. An increase in the number of white blood cells (WBCs) in CSF is
termed pleocytosis. Disease processes may lead to abrupt increases or decreases in numbers of cells.
CSF is examined for the presence of RBCs and WBCs. The cells are counted and identified by cell type; the percentage
of cell type is compared with the total number of WBCs or RBCs present. In general, inflammatory disease, hemorrhage,
neoplasms, and trauma cause an elevated WBC count.
Reference Values
Normal Normal CSF is essentially free of cells ( Table 5.5 and Table 5.6).
Table 5.5 Cell Counts
Differential

Adults

Newborn (0–14 d)

Lymphocytes
40%–80% 5%–35%
Monocytes
15%–45% 50%–90%
Polys (Neutrophils) 0%–6% 0%–8%

Table 5.6 Major Cells Seen in Microscopic Examination of CSF
Cell Types

Occurrence

Findings

Blast forms
Ependymal and
choroidal cells
Lymphocytes

Acute leukemia
Trauma (diagnostic procedures)

Lymphoblasts or myeloblasts
Clusters with distinct nuclei and distinct cell walls

Normal
Viral, tubercular, and fungal meningitis
Multiple sclerosis
Macrophages
Viral, tubercular, and fungal meningitis
RBCs in spinal fluid
Contrast media
Malignant cells
Metastatic carcinomas
Monocytes
Chronic bacterial meningitis
Viral and tubercular meningitis
Multiple sclerosis
Neutrophils
Bacterial meningitis
Early cases of viral, tubercular, and fungal
meningitis
Pia arachnoid
Normal, mixed reactions, including
mesothelial (PAM) cells lymphocytes, neutrophils, monocytes, and
plasma cells
Plasma cells
Multiple sclerosis
Tuberculosis
Meningitis
Sarcoidosis

All stages of development possible

May contain phagocytized RBCs (appearing as
empty vacuoles or ghost cells) and hemosiderin
granules
Clusters with fusing of cell borders and nuclei
Mixed with lymphocytes and neutrophils

Granules may be less prominent than in blood

Resemble young monocytes with a round, not
indented, nucleus
Transitional and classic forms seen

Adults: 0–5 WBCs/µL or 0–5 × 10 6 WBCs/L Newborn: 0–30 WBCs/µL or 0–30 × 10 6 WBCs/L Child: 0–15 WBCs/µL or
0–15 × 10 6 WBCs/L
Procedure Use tube 3 for counting the cells present in the CSF sample. The cells are counted by a manual counting
chamber or by electronic means. A CSF smear is made, and various types of cells present are counted to determine
differentiation of cells.
Clinical Implications
1. The total CSF cell count (includes neutrophils, lymphocytes, mixed cells, and cells after hemorrhage) is the most
sensitive index of acute inflammation of the CNS.
2. WBC counts >500 WBCs/µL or >500 × 10 6 WBCs/L usually arise from a purulent infection and are preponderantly
granulocytes (ie, neutrophils). Neutrophilic reaction classically suggests meningitis caused by a pyogenic organism,
in which case the WBC count can exceed 1000 WBCs/µL or 1000 × 10 6 WBCs/L and even reach 20,000 WBCs/µL
or 20,000 × 10 6 WBCs/L.
a. Increases in neutrophils are associated with the following conditions:
1. Bacterial meningitis (see Table 5.7)
Table 5.7 Abnormal CSF Findings in Types of Meningitis
Bacterial

Viral

Tubercular

Fungal

Total WBCs
Differential

Increased
Neutrophils
present

Increased
Lymphocytes
present

Increased
Lymphocytes and
monocytes present

Protein

Marked
increase

Moderate
increase

Glucose

Markedly
decreased
Increased
LD
isoenzymes 4
and 5
increased
Positive

Normal

Moderate to marked
increase; clots occur
with protein >150
mg/dL (>1500 mg/L)
Decreased

Increased
Lymphocytes
and monocytes
present
Moderate to
marked increase

Lactate
LDH fractions

Limulus amebocyte
Lysate: indicator of
endotoxin produced by
gram-negative bacteria
(Not affected by antibiotic
therapy)

Normal
LD isoenzymes
1, 2, and 3
increased

Increased
LD isoenzymes 1, 2,
and 3 increased

—

Pellicle formation
when protein >150
mg/dL (>1500 mg/L)

Normal to
decreased
Increased
—

Positive India
ink with
neoformans

3.

4.

5.
6.

7.
8.
9.
10.
11.

2. Early viral meningitis
3. Early tubercular meningitis
4. Fungal mycositic meningitis
5. Amebic encephalomyelitis
6. Early stages of cerebral abscess
b. Noninfectious causes of neutrophilia include the following:
1. Reaction to CNS hemorrhage
2. Injection of foreign materials into the subarachnoid space (eg, x-ray contrast medium, anticancer drugs)
3. CSF infarct
4. Metastatic tumor in contact with CSF
5. Reaction to repeated lumbar puncture
WBC counts of 300–500/µL or 300–500 × 10 6 with preponderantly lymphocytes are indicative of the following
conditions:
a. Viral meningitis
b. Syphilis of CNS (ie, meningoencephalitis)
c. Tuberculous meningitis
d. Parasitic infestation of the CNS
e. Bacterial meningitis due to unusual organisms (eg, Listeria species)
f. Multiple sclerosis (MS) (reactive lymph present)
g. Encephalopathy caused by drug abuse
h. Guillain-Barré syndrome (15%)
i. Acute disseminated encephalomyelitis
j. Sarcoidosis of meninges
k. Human T-lymphotropic virus type III (HTLV III)
l. Aseptic meningitis due to peptic focus adjacent to meninges
m. Fungal meningitis
n. Polyneuritis
WBC counts with = 40% monocytes occur in the following conditions:
a. Chronic bacterial meningitis
b. Toxoplasmosis and amebic meningitis
c. MS
d. Rupture of brain abscess
Malignant cells (lymphocytes or histiocytes) may be present with primary and metastatic brain tumors, especially
when there is meningeal extension.
Increased numbers of plasma cells occur in the following conditions:
a. Acute viral infections
b. MS
c. Sarcoidosis
d. Syphilitic meningoencephalitis
e. Subacute sclerosing panencephalitis
f. Tuberculous meningitis
g. Parasitic infestations of CSF
h. Guillain-Barré syndrome
i. Lymphocytic reactions
Plasma cells are responsible for an increase in immunoglobulin G (IgG) and altered patterns in
immunoelectrophoresis.
Macrophages are present in tuberculous or viral meningitis and in reactions to erythrocytes, foreign substances, or
lipids in the CSF.
Ependymal and plexus cells may be present after surgical procedures or trauma to the CNS (not clinically
significant).
Blast cells appear in CSF when acute leukemia is present (lymphoblasts or myeloblasts).
Eosinophils are present in the following conditions:
a. Parasitic infections
b. Fungal infections
c. Rickettsial infections (Rocky Mountain spotted fever)
d. Idiopathic hypereosinophilic syndrome
e. Reaction to foreign materials in CSF (eg, drugs, shunts)
f. Sarcoidosis

Clinical Alert
Neutrophilic reaction classically suggests meningitis caused by a pyogenic organism.
Interventions
Pretest Patient Preparation
1. See page 296 for care before lumbar puncture.
2. Follow guidelines in Chapter 1 regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret abnormal cell counts. Monitor, intervene, and counsel as appropriate for infection and malignancy.
2. See page 296 for care after lumbar puncture .
3. Follow guidelines in Chapter 1 regarding safe, effective, informed posttest care.

CSF Glucose
The CSF glucose level varies with the blood glucose levels. It is usually about 60% of the blood glucose level. A blood
glucose specimen should be obtained at least 60 minutes before lumbar puncture for comparisons. Any changes in blood
sugar are reflected in the CSF approximately 1 hour later because of the lag in CSF glucose equilibrium time.
This measurement is helpful in determining impaired transport of glucose from plasma to CSF, increased use of glucose
in the CNS, and glucose utilization by leukocytes and microorganisms. The finding of a markedly decreased CSF glucose
level accompanied by an increased WBC count with a large percentage of neutrophils is indicative of bacterial
meningitis.
Reference Values
Normal Adult: 40–70 mg/dL or 2.2–3.9 mmol/L Child: 60–80 mg/dL or 3.3–4.4 mmol/L CSF-to-plasma glucose ratio: <0.5
CSF glucose level: 60%–70% of blood glucose levels
Procedure Place 1 mL of CSF in a sterile tube. The glucose test should be done on tube 1 when three tubes of CSF are
taken. Accurate evaluation of CSF glucose requires a plasma glucose measurement. A blood glucose level ideally should
be drawn 1 hour before the lumbar puncture.
Clinical Implications
1. Decreased CSF glucose levels are associated with the following conditions:
a. Acute bacterial meningitis
b. Tuberculosis, fungal, and amebic meningitis
c. Systemic hypoglycemia
d. Subarachnoid hemorrhage
2. CSF glucose levels are uncommonly decreased in the following conditions:
a. Malignant tumor with meningeal involvement
b. Acute syphilitic meningitis
c. Nonbacterial meningoencephalitis
3. Increased CSF glucose levels are associated with diabetes and diabetic hyperglycemia. Elevated CSF levels are
always a result of high plasma values.
Interfering Factors
1. Falsely decreased levels may be due to cellular and bacterial metabolism if the test is not performed immediately
after specimen collection.
2. A traumatic tap may produce misleading results owing to glucose present in blood.
3. See Appendix J for drugs that affect test outcomes.

Clinical Alert
1. All types of organisms consume glucose; therefore, decreased glucose levels reflect abnormal activity.
2. The panic value for CSF glucose level is <20 mg/dL (<1.1 mmol/L); below this level, damage to the CNS will
occur.
3. The findings of a markedly decreased CSF glucose and an increased WBC count with a high percentage of
neutrophils are indicative of bacterial meningitis.
Interventions
Pretest Patient Preparation
1. See page 296 for care before lumbar puncture.
2. Explain the need for a blood specimen test for glucose to compare with CSF glucose.
3. Follow guidelines in Chapter 1 regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret abnormal CSF glucose levels and correlate with the presence of meningitis, cancer, hemorrhage, and
diabetes. Monitor and intervene appropriately to prevent complications.
2. See page 296 for care after lumbar puncture .
3. Follow guidelines in Chapter 1 regarding safe, effective, informed posttest care.
CSF Glutamine
Glutamine is synthesized in brain tissue from ammonia and alpha-ketoglutarate. Production of glutamine provides a
mechanism for removing the ammonia, a toxic metabolic waste product, from the CNS.
The determination of CSF glutamine level provides an indirect test for the presence of excess ammonia in the CSF. As
the concentration of ammonia in the CSF increases, the supply of alpha-ketoglutarate becomes depleted; consequently,
glutamine can no longer be produced to remove the toxic ammonia, and coma ensues. A CSF glutamine test is therefore
frequently requested for patients with coma of unknown origin. A glutamine value of >35 mg/dL (>2.4 mmol/L) usually
results in loss of consciousness.
Reference Values
Normal 8–18 mg/dL or 0.4–1.2 mmol/L

Procedure
1. Use 1 mL of CSF for the glutamine test. Tube 1 is used for this chemistry test.
2. Centrifuge the samples if cells are present.
Clinical Implications Increased CSF glutamine levels are associated with the following conditions:
1. Hepatic encephalopathy (glutamine values >35 mg/dL or >2.4 mmol/L are diagnostic)
2. Reye's syndrome
3. Encephalopathy secondary to hypercapnia or sepsis
Interventions
Pretest Patient Preparation
1. See page 296 for care before lumbar puncture.
2. Follow guidelines in Chapter 1 regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret abnormal glutamine levels and correlate with clinical symptoms. Monitor and intervene appropriately to
prevent complications.
2. See page 296 for care after lumbar puncture .
3. Follow guidelines in Chapter 1 regarding safe, effective, informed posttest care.
CSF Lactic Acid
The source of CSF lactic acid is CNS anaerobic metabolism. Lactic acid in CSF varies independently with the level of
lactic acid in the blood. Destruction of tissue within the CNS because of oxygen deprivation causes the production of
increased CSF lactic acid levels. Thus, elevated CSF lactic acid levels can result from any condition that decreases the
flow of oxygen to brain tissues.
The CSF lactic acid test is used to differentiate between bacterial and nonbacterial meningitis. Elevated CSF lactate
levels are not limited to meningitis and can result from any condition that decreases the flow of oxygen to the brain. CSF
lactate levels are frequently used to monitor severe head injuries.
Reference Values
Normal Adult: 10–22 mg/dL or 1.1–2.4 mmol/L Newborn: 10–60 mg/dL or 1.1–6.7 mmol/L
Procedure
1. Collect 0.5 mL of CSF in a sterile test tube; tube 1 should be used.
2. Refrigerate the sample.
Clinical Implications Increased CSF lactic acid levels are associated with the following conditions:
1.
2.
3.
4.
5.
6.

Bacterial meningitis (>38 mg/dL or >4.2 mmol/L)
Brain abscess or tumor
Cerebral ischemia
Cerebral trauma
Seizures
Stroke (cerebral infarct)

Interfering Factors Traumatic tap causes elevated levels: RBCs contain large amounts of lactate. Hemolyzed or
xanthochromic specimens will give falsely elevated results.
Interventions
Pretest Patient Preparation
1. See page 296 for care before lumbar puncture.
2. Follow guidelines in Chapter 1 regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes; monitor and intervene appropriately to detect CNS disease and prevent complications.
Results must be interpreted in light of clinical symptoms.
2. See page 296 for care after lumbar puncture .
3. Follow guidelines in Chapter 1 regarding safe, effective, informed posttest care.

Clinical Alert
Increases in CSF lactic acid levels must be interpreted in light of the clinical findings and in conjunction with glucose
levels, protein levels, and cell counts in the CSF. Equivocal results in some instances of aseptic meningitis may lead to
erroneous diagnosis of a bacterial etiology. Increased lactate in CSF following head injury suggests poor prognosis.

CSF Lactate Dehydrogenase (LD/LDH); CSF Lactate Dehydrogenase (LDH) Isoenzymes
Although many different enzymes have been measured in CSF, only lactate dehydrogenase (LDH) appears useful
clinically. Sources of LDH in normal CSF include diffusion across the blood-CSF barrier, diffusion across the brain-CSF
barrier, and LDH activity in cellular elements of the CSF, such as leukocytes, bacteria, and tumor cells. Because brain
tissue is rich in LDH, damaged CNS tissue can cause increased levels of LDH in the CSF.
High levels of LDH occur in about 90% of cases of bacterial meningitis and in only 10% of cases of viral meningitis.
When high levels of LDH do occur in viral meningitis, the condition is usually associated with encephalitis and a poor
prognosis. Tests of LDH isoenzymes have been used to improve the specificity of LDH measurements and are useful for
making the differential diagnosis of viral versus bacterial meningitis (see Chap. 6 for a complete description of
isoenzymes). Elevated LDH levels following resuscitation predict a poor outcome in patients with hypoxic brain injury.
Reference Values
Normal Adults: <20 U/L or approximately 10% of serum levels
Procedure
1. Obtain 1 mL of CSF for the LDH test; use tube 1 for LDH examination.
2. Take the sample to the laboratory as quickly as possible.
Clinical Implications
1. Increased CSF/LDH levels are associated with the following conditions:
a. Bacterial meningitis (90% of cases)
b. Viral meningitis (10% of cases)
c. Massive cerebrovascular accident
d. Leukemia or lymphoma with meningeal infiltration
e. Metastatic carcinoma of the CNS
2. The presence of CSF/LDH isoenzymes 1, 2, and 3 reflects a CNS lymphocytic reaction, suggesting viral meningitis.
3. The CSF/LDH isoenzyme pattern reflects a granulocytic (neutrophilic) reaction with LDH isoenzymes 4 and 5,
suggesting bacterial meningitis.
4. High levels of CSF/LDH isoenzymes 1 and 2 suggest extensive CNS damage and a poor prognosis (ie, they are
indicative of destruction of brain tissue).
5. CSF/LDH isoenzymes 3 and 4 suggest lymphatic leukemia or lymphoma.
Interfering Factors For the LDH test to be valid, CSF must not be contaminated with blood. A traumatic lumbar tap will
make results difficult to interpret.
Interventions
Pretest Patient Preparation
1. See page 296 for care before lumbar puncture.
2. Follow guidelines in Chapter 1 regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret abnormal LDH test patterns and monitor and intervene appropriately to detect and prevent complications.
2. See page 296 for care after lumbar puncture .
3. Follow guidelines in Chapter 1 regarding safe, effective, informed posttest care.
CSF Total Protein
The CSF normally contains very little protein because the protein in the blood plasma does not cross the blood-brain
barrier easily. Protein concentration normally increases caudally from the ventricles to the cisterns and finally to the
lumbar sac.
The CSF protein is a nonspecific but reliable indication of CNS pathology such as meningitis, brain abscess, MS, and
other degenerative processes causing neoplastic disease. Elevated CSF protein levels may be caused by increased
permeability of the blood-brain barrier, decreased resorption of the arachnoid villi, mechanical obstruction of the CSF
flow, or increased intrathecal immunologic synthesis.
Reference Values
Normal Results vary by method used; check with the laboratory for reference values. Total protein: Adults: 15–45 mg/dL
or 150–450 mg/L (lumbar) Adults: 15–25 mg/dL or 150–250 mg/L (cisternal) Adults: 5–15 mg/dL or 50–150 mg/L
(ventricular) Neonates: 15–100 mg/dL or 150–1000 mg/L (lumbar) Elderly patients (>60 years of age): 15–60 mg/dL or
150–600 mg/L (lumbar)
Procedure
1. Obtain 1 mL of CSF for protein analysis. Tube 1 should be used.
2. Measure serum protein levels concurrently to interpret CSF protein values.
Clinical Implications
1. Increased CSF protein occurs in the following situations:

a. Traumatic tap with normal CSF pressure: CSF initially streaked with blood, clearing in subsequent tubes
b. Increased permeability of blood-CSF barrier: CSF protein 100–500 mg/dL (1000–5000 mg/L)
1. Infectious conditions
i. Bacterial meningitis: Gram stain usually positive; culture may be negative if antibiotics have been
administered
ii. Tuberculosis: CSF protein 50–300 mg/dL (500–3000 mg/L); mixed cellular reaction typical
iii. Fungal meningitis: CSF protein 50–300 mg/dL (500–3000 mg/L); special stains helpful
iv. Viral meningitis: CSF protein usually <200 mg/dL (<2000 mg/L)
2. Noninfectious conditions
i. Subarachnoid hemorrhage: xanthochromia 2–4 hours after onset
ii. Intracerebral hemorrhage: CSF protein 20–200 mg/dL (200–2000 mg/L); marked fall in pressure after
removing small amounts of CSF; xanthochromia
iii. Cerebral thrombosis: slightly increased CSF protein in 40% of cases (usually, <100 mg/dL or <1000
mg/L)
iv. Endocrine disorders, diabetic neuropathy, myxedema, hyperadrenalism, hypoparathyroidism: CSF protein
50–150 mg/dL (500–1500 mg/L) in ˜50% of cases
v. Metabolic disorders, uremia, hypercalcemia, hypercapnia, dehydration: CSF protein slightly elevated
(usually, <100 mg/dL or <1000 mg/L)
vi. Drug toxicity, ethanol, phenytoin, phenothiazines: CSF protein slightly elevated in about 40% of cases
(usually, <200 mg/dL or <2000 mg/L)
c. Obstruction to circulation of CSF occurs in the following circumstances:
1. Mechanical obstruction (eg, tumor, abscess), herniated disk: rapid fall in pressure (yellow CSF, contains
excess protein)
2. Loculated effusion of CSF: repeated taps may show a progressive increase in CSF protein; diagnosis by
myelography
d. Increased CSF/IgG synthesis occurs in the following conditions:
1. MS: CSF protein level slightly increased
2. Subacute sclerosing panencephalitis: increased CSF protein
3. Neurosyphilis: CSF protein normal or slightly increased (usually, <100 mg/dL or <1000 mg/L)
e. Increased CSF/IgG synthesis and increased permeability of blood-CSF barrier occur in the following conditions:
1. Guillain-Barré syndrome (infectious polyneuritis): CSF protein usually 100–400 mg/dL (1000–4000 mg/L)
2. Collagen diseases (eg, periarteritis, lupus): CSF protein usually < 400 mg/dL (or <4000 mg/L)
3. Chronic inflammatory demyelinating polyradiculopathy
f. Decreased CSF protein occurs in the following conditions:
1. Leakage of CSF due to trauma
2. Removal of a large volume of CSF
3. Intracranial hypertension
4. Hyperthyroidism
5. Young children between 6 months and 2 years of age

Clinical Alert
More than 1000 mg/dL (>10,000 mg/L) of protein in CSF suggests subarachnoid block. In a complete spinal block, the
lower the tumor location, the higher the CSF protein value.
Interfering Factors
1. Hemolyzed or xanthochromic drugs may falsely depress results.
2. Traumatic tap will invalidate the protein results.
3. See Appendix J for drugs that affect test outcomes.
Interventions
Pretest Patient Preparation
1. See page 296 for care before lumbar puncture.
2. Follow guidelines in Chapter 1 regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret abnormal CSF protein levels; monitor for both infectious and noninfectious conditions and intervene
appropriately to prevent and detect complications.
2. See page 296 for care after lumbar puncture .
3. Follow guidelines in Chapter 1 regarding safe, effective, informed posttest care.
CSF Albumin and Immunoglobulin G (IgG)
Albumin composes the majority of the proteins in CSF. The albumin and IgG that are present in normal CSF are derived
from the serum. Increased levels of either or both are indicative of damage to the blood-CNS barrier.
The combined measurement of albumin and IgG is used to evaluate the integrity and permeability of the blood-CSF
barrier and to measure the synthesis of IgG within the CNS. The IgG index is the most sensitive method to determine
local CNS synthesis of IgG and to detect increased permeability of the blood-CNS barrier.

The IgG index method is superior to the IgG-to-albumin ratio or measurement of IgG only. Normal persons usually have
an index < 0.60. With MS, the index is > 0.77.
Reference Values
Normal Albumin: 10–35 mg/dL or 1.5–5.3 µmol/L IgG: <4.0 mg/dL or <40 mg/L CSF-to-serum albumin index: <9.0

IgG index: 0.3–0.60 CSF/IgG-to-albumin ratio: 0.009–0.25
Procedure
1. Obtain 0.5 mL of CSF in a sterile tube.
2. Freeze the sample if the determination is not done immediately.
Clinical Implications
1. Increased CSF albumin occurs in most of the same conditions as increased total protein, especially:
a. Lesions of the choroid plexus
b. Blockage of CSF flow
c. Bacterial meningitis
d. Guillain-Barré syndrome
e. Many infectious diseases, such as typhoid fever, tularemia, diphtheria, and septicemia
f. Malignant neoplasms of the CNS
2. Increased CSF/IgG-to-albumin index (increased IgG, normal albumin) occurs in the following conditions:
a. MS
b. Subacute sclerosing leukoencephalitis
c. Neurosyphilis
d. Chronic phases of CNS infections (subacute sclerosing panencephalitis [SSPE])
Interfering Factors A traumatic tap will invalidate the results.
Interventions
Pretest Patient Preparation
1. See page 296 for care before lumbar puncture.
2. Follow guidelines in Chapter 1 regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes; monitor and intervene appropriately to prevent and detect complications.
2. See page 296 for care after lumbar puncture .
3. Follow guidelines in Chapter 1 regarding safe, effective, informed posttest care.
CSF Protein Electrophoresis; Oligoclonal Bands; Multiple Sclerosis Panel
Agarose gel electrophoresis of concentrated CSF is used to detect oligoclonal bands, defined as two or more discrete
bands in the gamma region that are absent or of less intensity than in the concurrently tested patient's serum.
Fractionation (ie, electrophoresis) of CSF is used to evaluate bacterial and viral infections and tumors of the CNS.
However, the most important application of CSF protein electrophoresis is the detection and diagnosis of MS.
Abnormalities of CSF in MS include an increase in total protein, primarily from IgG, which is the main component of the
gamma-globulin fraction. Abnormal immunoglobulins migrate as discrete, sharp bands, called oligoclonal bands. This is
the pattern observed in MS: a pattern of discrete bands within the gamma-globulin portion of the electrophoretic pattern.
However, oligoclonal bands are found in the CSF of patients with other types of nervous system disorders of the immune
system, including human immunodeficiency virus (HIV).
Electrophoresis is also the method of choice to determine whether a fluid is actually CSF. Identification can be made
based on the appearance of an extra band of transferrin (referred to as “TAV”), which occurs in CSF and not in serum.
Reference Values
Normal Globulins: Oligoclonal banding: none present; alpha 1: 2%–7% IgG synthesis rate: 0.0–8.0 mg/day; alpha 2:
4%–12% IgG-to-albumin ratio: 0.09–0.25; beta: 8%–18% Prealbumin: 2%–7%; gamma: 3%–12% Albumin: 56%–76%
Procedure
1. Obtain 3 mL of CSF for this test. Use tube 1. The sample must be frozen if the test is not performed immediately.
2. Apply a sample of the concentrate to a thin-layer agarose gel. Subject the agarose gel to electrophoresis. CSF is
concentrated approximately 80-fold by selective permeability. Serum electrophoresis must be done concurrently for
interpretation of the bands.
Clinical Implications

1. Increases in CSF IgG or in the IgG-to-albumin index occur in the following conditions:
a. MS
b. Subacute sclerosis panencephalitis
c. Tumors of the brain and meninges
d. Chronic CNS infections
e. Some patients with meningitis, Guillain-Barré syndrome, lupus erythematosus involving the CNS, and other
neurologic conditions
2. Increases in the CSF albumin index occur in the following conditions:
a. Obstruction of CSF circulation
b. Damage to the CNS blood-brain barrier
c. Diabetes mellitus
d. Systemic lupus erythematosus of the CNS
e. Guillain-Barré syndrome
f. Polyneuropathy
g. Cervical spondylosis
3. Increased CSF gamma-globulin and the presence of oligoclonal bands occur in the following conditions:
a. MS
b. Neurosyphilis
c. Subacute sclerosing panencephalitis
d. Cerebral infarction
e. Viral and bacterial meningitis
f. Progressive rubella panencephalitis
g. Cryptococcal meningitis
h. Idiopathic polyneuritis
i. Burkitt's lymphoma
j. HIV-I (acquired immunodeficiency syndrome [AIDS])
k. Guillain-Barré syndrome
4. Increased CSF synthesis of IgG occurs in the following conditions:
a. MS (90% of definite cases)
b. Inflammatory neurologic diseases
c. Postpolio syndrome

Clinical Alert
1. A serum electrophoresis must be done at the same time as the CSF electrophoresis. An abnormal result is the
finding of two or more bands in the CSF that are not present in the serum specimen. (See Figure 5.3.)

FIGURE 5.3 Cerebrospinal fluid report—patient with multiple sclerosis. Source: Reiber H, Peter JB:
Cerebrospinal fluid analysis: Disease-related data patterns and evaluation programs. J Neuro Sci, 184:101–122,
2001.
2. Oligoclonal bands are not specific for multiple sclerosis; however, the sensitivity is 83% to 94%.
3. Diagnostic differentiation between MS and CSF autoimmune disease relies on further testing (eg, antinuclear
antibodies [ANAs] in blood [see Chap. 8)].
Interfering Factors
1. A traumatic tap invalidates the results.
2. Recent myelography affects the results.
Interventions
Pretest Patient Preparation
1. See page 296 for care before lumbar puncture.
2. Follow guidelines in Chapter 1 regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome; monitor for MS and other CNS disorders and intervene appropriately to prevent and detect
complications.

2. See page 296 for care after lumbar puncture .
3. Follow guidelines in Chapter 1 regarding safe, effective, informed posttest care.
CSF Syphilis Serology
Reference Values
Normal Negative (ie, nonreactive) for syphilis. Neurosyphilis is characterized by an increase in protein, an increase in
the number of lymphocytes, and a positive test for syphilis (see Chap. 8). Use CSF VDRL test, only if serum VDRL test is
positive, to rule in, not rule out, neurosyphilis. Do not use VDRL to evaluate the results of syphilis therapy.
BIBLIOGRAPHY
Bishop ML, Duben-Engelkirk JL, Fody EP: Clinical Chemistry—Principles, Procedures, Correlations, 4th ed. Philadelphia, Lippincott Williams &
Wilkins, 1999
Burton CA, Ashwood ER: Tietz Textbook of Clinical Chemistry, 3rd ed. Philadelphia, WB Saunders, 1999
Henry JB (ed): Clinical Diagnosis and Management by Laboratory Methods, 20th ed. Philadelphia, WB Saunders, 2001
Leavelle DE (ed): Interpretive Handbook: Interpretive Data for Diagnostic Laboratory Tests. Rochester, MN, Mayo Medical Laboratories, 2001
Lehman CA (ed): Saunders Manual of Clinical Laboratory Science. Philadelphia, WB Saunders, 1998
Knight JA: Advances in the analysis of cerebral spinal fluid. Am Clin Lab Sci 27: 93, 1997
McBride LJ: Textbook of Urinalysis and Body Fluids. Philadelphia, Lippincott-Raven, 1998
Regeniter A, Steiger JU, Scholer A, Huber PR, Siede WH: Windows to the ward; Graphically oriented report forms: Presentation of complex,
interrelated laboratory data for electrophoresis/immunofixation, cerebrospinal fluid, and urinary protein profiles. Clinical Chemistry, 49:1, 41–50,
2003
Reiber H, Peter JB: Cerebrospinal fluid analysis: Disease-related patterns and evaluation programs. J Neurol Science, 184:101–122, 2001
Ryngsrud MK: Urinalysis and Body Fluids: A Color Text and Atlas. St. Louis, Mosby, 1998
Smith S, Forman D: Laboratory analysis of cerebrospinal fluid. Clin Lab Sci 7(4): 32–38, 1994
Strasinger S, DiLorenzo MS. Urinalysis and Body Fluids, 4th ed. Philadelphia, FA Davis, 2001
Tietz NB (ed): Clinical Guide to Laboratory Tests, 3rd ed. Philadelphia, WB Saunders, 1995
Wallach J: Interpretation of Diagnostic Tests, 7th ed. Philadelphia, Lippincott Williams & Wilkins, 2000
Weiner WJ, Shulman LM (eds): Emergent and Urgent Neurology, 2nd ed. Philadelphia, Lippincott-Raven, 1998
Young DS: Effects of Drugs on Clinical Laboratory Tests, 5th ed. Washington, DC, AACC Press, 1999

6 Chemistry Studies
A Manual of Laboratory and Diagnostic Tests

6
Chemistry Studies
OVERVIEW OF CHEMISTRY STUDIES
General Biochemical Profiles
Use of the Autoanalyzer
NOTE
DIABETES TESTING (TYPE 1 AND TYPE 2), BLOOD GLUCOSE, BLOOD SUGAR, AND RELATED TESTS AND CRITERIA FOR DIAGNOSING DIABETES
C-Peptide
Glucagon
Insulin
Fasting Blood Glucose (FBG); Fasting Blood Sugar (FBS); Fasting Plasma Glucose (FPG); Casual Plasma Glucose (PG)
Clinical Alert
Gestational Diabetes Mellitus (GDM); O'Sullivan Test (1-h Gestational Diabetes Mellitus Screen)
Glucose Tolerance Test (GTT); Oral Glucose Tolerance Test (OGTT)
Glycosylated Hemoglobin (Hb A1c); Glycohemoglobin (G-Hb); Glycated Hemoglobin (GhB); Diabetic Control Index; Glycated Serum Protein (GSP), Fructosamine
Lactose Tolerance; Breath Hydrogen Test
END PRODUCTS OF METABOLISM AND OTHER TESTS
Ammonia (NH3)
Bilirubin
Neonatal Bilirubin, Total and Fractionated (“Baby Bili”)
Blood Urea Nitrogen (BUN, Urea Nitrogen)
Albumin
Prealbumin (PAB)
Cholinesterase, Serum (Pseudocholinesterase); Cholinesterase, Red Blood Cell (Acetylcholinesterase)
Creatinine
Cystatin C
Uric Acid
Lead (Pb)
Osteocalcin (Bone G1a Protein)
HORMONE TESTS
Androstenedione
Aldosterone
NOTE
Antidiuretic Hormone (ADH); Arginine Vasopressin Hormone
Atrial Natriuretic Factor (ANF), ANP and BNP
Chart 6.1 Heart Failure
Chart 6.2 Grading Heart Diseases
Cortisol (Hydrocortisone)
Cortisol Suppression (Dexamethasone Suppression; DST)
Cortisone Stimulation (Cosyntropin, Cortrosyn Stimulation); Adrenocorticotropin Hormone (ACTH) Stimulation
Gastrin
Growth Hormone (hGH); Somatotropin
Parathyroid Hormone Assay; Parathyrin; Parathormone (PTH-C-Terminal)
Somatomedin C (SM-C); Insulin-like Growth Hormone
FERTILITY TESTS
NOTE
Chorionic Gonadotropin; Human Chorionic Gonadotropin (hCG) ß Subunit; Pregnancy Test
Follicle-Stimulating Hormone (FSH); Luteinizing Hormone (LH)
Prolactin (hPRL)
Progesterone
Testosterone, Total and Free
ENZYME TESTS
Acid Phosphatase; Prostatic Acid Phosphatase (PAP)
Prostate-Specific Antigen (PSA)
Alanine Aminotransferase (Aminotransferase, ALT); Serum Glutamic-Pyruvic Transaminase (SGPT)
Alkaline Phosphatase (ALP), Total; 5'-Nucleotidase
Alkaline Phosphatase Isoenzymes (ISO)
Angiotensin-Converting Enzyme (ACE)
Amylase and Lipase
Aspartate Transaminase (Aminotransferase, AST); Serum Glutamic-Oxaloacetic Transaminase (SGOT)
Cardiac Troponin T (cTnT): Troponin I (cTnI)
Creatine Phosphokinase (CPK); Creatine Kinase (CK); CPK and CK Isoenzymes
Galactose-1-Phosphate Uridyltransferase (GPT); Galactokinase; Galactose-1-Phosphate
Hexosaminidase, Total and Isoenzyme A
Lactate Dehydrogenase (LD, LDH)
Lactate Dehydrogenase (LDH, LD) Isoenzymes (Electrophoresis)
Renin (Angiotensin); Plasma Renin Angiotensin (PRA)
Renin Stimulation/Challenge Test
Interpretation of Renin Stimulation Test
?-Glutamyltransferase (?-Glutamyl Transpeptidase, GGT, ?GT)
Homocysteine (tHcy)
Chart 6.3 Homocysteine Testing
a1-Antitrypsin (AAT)

DRUG MONITORING
Therapeutic Drug Management
Blood, Saliva, and Breath Alcohol Content (BAC; Ethanol [Ethyl Alcohol, ETOH])
LIPOPROTEIN TESTS/LIPOPROTEIN PROFILES
Cholesterol
High-Density Lipoprotein Cholesterol (HDL-C)
Very-Low-Density Lipoprotein (VLDL); Low-Density Lipoprotein (LDL)
Apolipoprotein A and B (Apo A-I, Apo B)
Triglycerides
Lipoprotein Electrophoresis
Free Fatty Acids; Fatty Acid Profile
THYROID FUNCTION TESTS
Patient Care for Thyroid Testing
Calcitonin
Free Thyroxine (FT4)
Free Triiodothyronine (FT3)
Free Thyroxine Index (FTI, T7)
Neonatal Thyroid-Stimulating Hormone (TSH)
Neonatal Thyroxine (T4); Neonatal Screen for Hypothyroidism
Thyroglobulin (Tg)
Thyroid-Stimulating Hormone (Thyrotropin; TSH)
Thyroxine-Binding Globulin (TBG)
Thyroxine (T4), Total
Triiodothyronine (T3), Total
Triiodothyronine Uptake (T3 U)
BIBLIOGRAPHY

OVERVIEW OF CHEMISTRY STUDIES
Blood chemistry testing identifies many chemical blood constituents. It is often necessary to measure several blood
chemicals to establish a pattern of abnormalities. A wide range of tests can be grouped under the headings of enzymes,
electrolytes, blood sugars, lipids, hormones, proteins, vitamins, minerals, and drug investigation. Other tests have no
common denominator. Selected tests serve as screening devices to identify target organ damage. When collecting
specimens for chemistry studies, refer to Standard/Universal Precautions in Appendix A, Latex and Rubber Allergy
Precautions in Appendix B, and Guidelines for Specimen Transport and Storage in Appendix E, and always refer to
Appendix J for Effects of the Mostly Commonly Used Drugs on Frequently Ordered Laboratory Tests.
General Biochemical Profiles
Profiles are a group of select tests that screen for certain conditions. Some of the more common profiles or panels are
listed in Table 6.1.

Table 6.1 Common Screening Profiles
Group Headings

Tests Suggested

Cardiac markers (MI)
Electrolyte panel
Kidney functions/disease

Chem panels, cardiac troponin, CK, MB, homocysteine
Na, K, Cl, CO 2, pH
BUN, phosphorus, LDH, creatinine, creatinine clearance, total protein, A/G ratio, albumin,
calcium, glucose, CO 2
Cholesterol, triglycerides, HDL, lipoprotein electrophoresis (LDL, VLDL, HDL)
Total bilirubin, alkaline phosphatase, GGT, total protein, A/G ratio, albumin, AST, LDH,
viral hepatitis panel, PT
T 3 uptake, free T 4 , Total T 4 , T 7 , FTI, TSH
Chloride, sodium, potassium, carbon dioxide, glucose, BUN, creatinine
Blood lipid glucose

Lipids (coronary risk)
Liver function/disease

Thyroid function
Basic metabolic screen
Syndrome X (metabolic
syndrome)
A/G ratio, albumin/globulin ratio; AST, aspartate aminotransferase; BUN, blood urea nitrogen; CK, creatine kinase; FTI,
free thyroxine index; HDL, high-density lipoproteins; LDH, lactate dehydrogenase; LDL, low-density lipoproteins; PT,
prothrombin time; TSH, thyroid-stimulating hormone; VLDL, very-low-density lipoprotein.

Use of the Autoanalyzer
Sophisticated automated instrumentation makes it possible to conduct a wide variety of chemical tests on a single sample
of blood and to report results in a timely manner. Numerical results may be reported with low, high, panic, toxic, or D (ie,
fails Delta check) comments along with normal reference range. Computerized interfaces allow direct transmission of
results between laboratory and clinical settings. “Hard copy” printouts can then become a permanent part of the health
care record. Not only does this method of record keeping provide a baseline for future comparisons, but it can also allow
unsuspected diseases to be uncovered and can lead to early diagnosis when symptoms are vague or absent. Chemistry
tests may be termed chem panels, SMAC, chem 2 zyme profiles, and SMAS. These terms refer to the company that
produces the auto analyzer. A list of standard panels follows in Table 6.2.

Table 6.2 Standard Panels
Panel Tests

Specimen Collection

ARTHRITIS PANEL (ARTH PN)
Uric acid, ESR, ANA (antinuclear antibody screen), rheumatoid factor
BASIC METABOLIC PANEL (BC MET)
Creatinine, CO 2 , chloride, glucose, potassium, sodium, BUN, calcium
COMPREHENSIVE METABOLIC PANEL (CM MET)
Albumin, alkaline phosphatase, ALT, AST, total bilirubin, calcium, CO 2,
chloride, creatinine, glucose, potassium, sodium, total protein, BUN
ELECTROLYTES (LYTES)
CO 2, chloride, potassium, sodium
HEPATIC FUNCTION PANEL (HEPFUN)
ALT, albumin, alkaline phosphatase, AST, direct bilirubin and total bilirubin,
total protein
ACUTE HEPATITIS PANEL (ACUTE HEP)
Hepatitis A, AB, IgM, hepatitis B core antibody, IgM, hepatitis B surface
antigen, IgM, hepatitis C, AB
LIPID PANEL (LIPID PN)
Cholesterol, HDL, triglycerides (LDL and CHO/HDL ratio included, as
calculated values)
OBSTETRIC PANEL (OB PN)

Two 7-mL red topped tubes and 1
lavender-topped tube
1 mL unhemolyzed serum (one SST tube)

CBC WITH DIFF
Type and Rh, antibody screen, RPR, rubella Ab-IgG, hepatitis B surface
antigen
PRENATAL SCREEN (PRESCP)
Type and RH, antibody screening and studies if indicated, RPR for syphilis,
rubella Ab-IgG, hepatitis B surface antigen

1 mL unhemolyzed serum (one SST tube)

1 mL unhemolyzed serum (one SST tube)
1 mL unhemolyzed serum (one SST tube)

One 7-mL red-topped tube

2 mL serum (one SST tube)

One 7-mL red-topped tube, one
lavender-topped tube, and one SST tube

One lavender-topped tube, one 7-mL redtopped tube, and one SST tube

NOTE
Normal or reference values for any chemistry determination vary with the method or assay employed. For example,
differences in substrates or temperature at which the assay is run will alter the “normal” range. Thus, “normal ranges”
vary from laboratory to laboratory.
The following is a list of routine automated tests performed commonly in the chemistry department:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.

Alanine aminotransferase (ALT)
Albumin
Alkaline phosphatase
Amylase
Aspartate aminotransferase (AST)
Bilirubin, direct
Bilirubin, total
Calcium
Carbon dioxide (CO 2)
Chloride
Cholesterol
Cholesterol-HDL
Creatine kinase
Creatinine
?-Glutamyl transferase (GGT)
Glucose
Iron
Lactate dehydrogenase (LDH)
LDL cholesterol (calculated)
Magnesium
Phosphorous, inorganic
Potassium
Protein, total
Sodium
Total iron binding (calculated)
Triglycerides
Unbound iron binding (UIBC)
Urea nitrogen
Uric acid

DIABETES TESTING (TYPE 1 AND TYPE 2), BLOOD GLUCOSE, BLOOD SUGAR, AND RELATED

TESTS AND CRITERIA FOR DIAGNOSING DIABETES
C-Peptide
C-peptide is formed during the conversion of pro-insulin to insulin. Pro-insulin is cleaved (holds a and ß insulin chains
together in the pro-insulin molecule) into insulin and biologically inactive C-peptide. C-peptide assay provides distinction
between exogenous and endogenous circulating insulin.
The main use of C-peptide is to evaluate hypoglycemia. C-peptide levels provide reliable indicators for pancreatic, B, and
secretory functions and insulin secretions. In a patient with type 1 diabetes mellitus, C-peptide measurements can be an
index of insulin production and mark endogenous ß-cell activity. C-peptide levels can also be used to confirm suspected
surreptitious insulin injections (ie, factitious hypoglycemia). Findings in these patients reveal that insulin levels are
usually high, insulin antibodies may be high, but C-peptide levels are low or undetectable. This test also monitors the
patient's recovery after excision of an insulinoma. Rising C-peptide levels suggest insulinoma tumor recurrence or
metastases.
Reference Values
Normal Fasting: 0.51–2.72 ng/mL or 0.17–0.90 mmol/L Varies with laboratory.
Procedure
1. Draw a 1-mL venous blood sample from a fasting patient using a red-topped chilled tube. Serum is needed for test.
Date and time must be correct. Centrifuge blood for 30 minutes.
2. Separate the blood at 4°C and freeze if it will not be tested until later.
3. Remember that a sample for glucose testing is usually drawn at the same time.
Clinical Implications
1. Increased C-peptide values occur in the following conditions:
a. Endogenous hyperinsulinism (insulinemia)
b. Oral hypoglycemic drug ingestion
c. Pancreas or ß-cell transplantation
d. Insulin-secreting neoplasms (islet cell tumor)
e. Type 2 diabetes mellitus (non–insulin-dependent)
2. Decreased C-peptide values occur in the following conditions:
a. Factitious hypoglycemia (surreptitious insulin administration)
b. Radical pancreatectomy
c. Type 1 diabetes mellitus
3. C-peptide stimulation test can determine the following:
a. Distinguishes between type 1 and type 2 diabetes mellitus.
b. Patients with diabetes whose C-peptide stimulation values are >1.8 ng/mL (>0.59 nmol/L) can be managed
without insulin treatment.
Interfering Factors Increased C-peptide:
1. Renal failure
2. Ingestion of sulfonylurea

Clinical Alert
To differentiate insulinoma from factitious hypoglycemia, an insulin/C-peptide ratio can be performed.
<1.0 Ratio: increased endogenous insulin secretion
>1.0 Ratio: exogenous insulin
Interventions
Pretest Patient Care
1.
2.
3.
4.
5.

Explain the test purpose and blood-drawing procedure. Obtain history of signs and symptoms of hypoglycemia.
Ensure that the patient fasts, except for water, for 8 to 12 hours before blood is drawn.
Remember that radioisotope test, if necessary, should take place after blood is drawn for C-peptide levels.
If the C-peptide stimulation test is done, give IV glucagon after a baseline value blood sample is drawn.
Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Aftercare
1. Resume normal activities.
2. Interpret test results and monitor as appropriate. Explain possible need for further testing. See Chapter 8 for insulin
antibody testing.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Glucagon
Glucagon is a peptide hormone that originates in the a cells of the pancreatic islets of Langerhans. This hormone

promotes glucose production in the liver. Normally, glucagon is a counterbalance to insulin. Glucagon provides a
sensitive, coordinated control mechanism for glucose production and storage. For example, low blood glucose levels
cause glucagon to stimulate glucose release into the bloodstream, whereas elevated blood glucose levels reduce the
amount of circulating glucagon to abut 50% of that found in the fasting state. The kidneys also affect glucagon
metabolism. Elevated fasting glucagon levels in the presence of renal failure return to normal levels following successful
renal transplantation. Abnormally high glucagon levels drop toward normal once insulin therapy effectively controls
diabetes. However, when compared with a healthy person, glucagon secretion in the person with diabetes does not
decrease after eating carbohydrates. Moreover, in healthy persons, arginine infusion causes increased glucagon
secretion.
This test measures glucagon production and metabolism. A glucagon deficiency reflects pancreatic tissue loss. Failure of
glucagon levels to rise during arginine infusion confirms glucagon deficiency. Hyperglucagonemia (ie, elevated glucagon
levels) occurs in diabetes, acute pancreatitis, and situations in which catecholamine secretion is stimulated (eg,
pheochromocytoma, infection).
Reference Values
Normal Adults: 20–100 pg/mL or 20–100 ng/L Children: 0–148 pg/mL or 0–148 ng/L Newborns: 0–1750 pg/mL or
0–1750 ng/L Normal ranges vary with different laboratories.

Clinical Alert
During a glucose tolerance test (GTT) in healthy persons, glucagon levels will decline significantly compared with
baseline fasting levels as normal hyperglycemia takes place during the first hour of testing.
Procedure
1. Draw a 5-mL blood sample from a fasting person into a chilled EDTA Vacutainer tube containing aprotinin (Trasylol)
proteinase inhibitor. Special handling is required because glucagon is very prone to enzymatic degradation. Tubes
used to draw blood must be chilled before the sample is collected and placed on ice afterward, and plasma must be
frozen as soon as possible after centrifuging.
2. Observe standard precautions. Place specimen in a biohazard bag.
Clinical Implications
1. Increased glucagon levels are associated with the following conditions:
a. Acute pancreatitis (eg, pancreatic a-cell tumor)
b. Diabetes mellitus: persons with severe diabetic ketoacidosis are reported to have fasting glucagon levels five
times normal despite marked hyperglycemia.
c. Glucagonoma (familial) may be manifested by three different syndromes:
1. The first syndrome exhibits a characteristic skin rash, necrolytic migratory erythema, diabetes mellitus or
impaired glucose tolerance, weight loss, anemia, and venous thrombosis. This form usually shows elevated
glucagon levels (>1000 pg/mL or >1000 ng/L) (diagnostic).
2. The second syndrome occurs with severe diabetes.
3. The third form is associated with multiple endocrine neoplasia syndrome and can show relatively lower
glucagon levels as compared with the others.
d. Chronic renal failure
e. Hyperlipidemia
f. Stress (trauma, burns, surgery)
g. Uremia
h. Hepatic cirrhosis
i. Hyperosmolality
j. Acute pancreatitis
k. Hypoglycemia
2. Reduced levels of glucagon are associated with the following conditions:
a. Loss of pancreatic tissue
1. Pancreatic neoplasms
2. Pancreatectomy
b. Chronic pancreatitis
c. Cystic fibrosis

NOTE
After glucose load, there is no suppression of glucagon in patients with glucagonoma.
Interventions
Pretest Patient Care
1. Explain purpose of test and blood-drawing procedure. A minimum 8-hour fast (no calorie intake for at least 8 hours)
is necessary before the test.
2. Promote relaxation in a low-stress environment; stress alters normal glucagon levels.
3. Do not administer radiopharmaceuticals within 1 week before the test.
4. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.

2. Interpret test outcome and monitor for the three different syndromes of glucagonoma.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Insulin
Insulin, a hormone produced by the pancreatic ß cells of the islets of Langerhans, regulates carbohydrate metabolism
together with contributions from the liver, adipose tissue, and other target cells. Insulin is responsible for maintaining
blood glucose levels at a constant level within a defined range. The rate of insulin secretion is primarily regulated by the
level of blood glucose perfusing the pancreas; however, it can also be affected by hormones, the autonomic nervous
system, and nutritional status.
Insulin levels are valuable for establishing the process of an insulinoma (ie, tumor of the islets of Langerhans). This test
is also used for investigating the causes of fasting hypoglycemic states and neoplasm differentiation. The insulin study
can be done in conjunction with a GTT or fasting blood glucose (FBG) test or a fasting plasma glucose (FPG) test.
Reference Values
Normal Immunoreactive Adults: 0–35 µIU/mL or 0–243 pmol/L Children: 0–10 µIU/mL or 0–69 pmol/L Free Adults: 0–17
µIU/mL or 0–118 pmol/L Children (prepubertal): 0–13 µIU/mL or 0–90 pmol/L
Procedure
1. Obtain a 5-mL blood sample from a fasting person; serum is preferred. Observe standard precautions. Heparinized
blood may be used.
2. If done in conjunction with a GTT, draw the specimens before administering oral glucose and again 30, 60, and 120
minutes after glucose ingestion (the same times as the GTT).
Clinical Implications
1. Increased insulin values are associated with the following conditions:
a. Insulinoma (pancreatic islet tumor). Diagnosis is based on the following findings:
1. Hyperinsulinemia with hypoglycemia (glucose <30 mg/dL or <1.66 mmol/L)
2. Persistent hypoglycemia together with hyperinsulinemia (>20 µIU/mL or >139 pmol/L) after tolbutamide
injection (rapid rise and rapid fall)
3. Failed C-peptide suppression with a plasma glucose level <30 mg/dL or <1.66 mmol/L and insulin/glucose
ratio >0.3.
b. Type 2 diabetes mellitus, untreated
c. Acromegaly
d. Cushing's syndrome
e. Endogenous administration of insulin (factitious hypoglycemia)
f. Obesity (most common cause)
g. Pancreatic islet cell hyperplasia
2. Decreased insulin values are found in the following conditions:
a. Type 1 diabetes mellitus, severe
b. Hypopituitarism

Clinical Alert
Panic range: >35 µIU/mL or >243 pmol/L (fasting)
Interfering Factors
1. Surreptitious insulin or oral hypoglycemic agent ingestion or injection causes elevated insulin levels (with low
C-peptide values).
2. Oral contraceptives and other drugs cause falsely elevated values.
3. Recently administered radioisotopes affect test results.
4. In the second to third trimester of pregnancy, there is a relative insulin resistance with a progressive decrease of
plasma glucose and immunoreactive insulin.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Ensure that the patient fasts from all food and fluid, except water, unless otherwise directed.
3. Be aware that because insulin release from an insulinoma may be erratic and unpredictable, it may be necessary
for the patient to fast for as long as 72 hours before the test.
4. Follow guidelines in Chapter 1 regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activity and diet.
2. Interpret test results and counsel appropriately. Obese patients may have insulin resistance and unusually high
fasting and postprandial (after eating) insulin levels. Explain possible need for further testing and treatment.
3. Follow guidelines in Chapter 1 regarding safe, effective, informed posttest care.

Clinical Alert
A potentially fatal situation may exist if the insulinoma secretes unpredictably high levels of insulin. In this case, the
blood glucose may drop to such dangerously low levels as to render the person comatose and unable to
self-administer oral glucose forms. Patients and their families must learn how to deal with such an emergency and to
be vigilant until the problem is treated.
Fasting Blood Glucose (FBG); Fasting Blood Sugar (FBS); Fasting Plasma Glucose (FPG); Casual Plasma
Glucose (PG)
Glucose is formed from carbohydrate digestion and conversion of glycogen to glucose by the liver. The two hormones
that directly regulate blood glucose are glucagon and insulin. Glucagon accelerates glycogen breakdown in the liver and
causes the blood glucose level to rise. Insulin increases cell membrane permeability to glucose, transports glucose into
cells (for metabolism), stimulates glycogen formation, and reduces blood glucose levels. Driving insulin into the cells
requires insulin and insulin receptors. For example, after a meal, the pancreas releases insulin for glucose metabolism,
provided there are enough insulin receptors. Insulin binds to these receptors on the surface of target cells such as are
found in fat and muscle. This opens the channels so that glucose can pass into cells, where it can be converted into
energy. As cellular glucose metabolism occurs, blood glucose levels fall. Adrenocorticotropic hormone (ACTH),
adrenocorticosteroids, epinephrine, and thyroxine also play key roles in glucose metabolism. See Chapter 11 for genetic
causes of type 1 and type 2 diabetes mellitus.
The American Diabetes Association (ADA) has begun using the term pre-diabetes, also known as impaired glucose
tolerance or impaired fasting glucose. Individuals with pre-diabetes demonstrate higher levels of blood plasma glucose
(PG) (110–125 mg/dL or 6.1–6.9 nmol/L) than normals (<110 mg/dL or <6.1 nmol/L) and, if left untreated, go on to
develop type 2 diabetes within 10 years.
Fasting blood plasma glucose (see Fig. 6.1) is a vital component of diabetes management. Abnormal glucose
metabolism may be caused by inability of pancreatic islet ß cells to produce insulin, reduced numbers of insulin
receptors, faulty intestinal glucose absorption, inability of the liver to metabolize glycogen, or altered levels of hormones
(eg, ACTH) that play a role in glucose metabolism.

FIGURE 6.1 The glucose continuum. FPG, fasting plasma glucose; OGTT, oral glucose tolerance test. (Source: The
American Association for Clinical Chemistry, Inc., Washington, DC, Clinical Laboratory News, 28 [6] June 2002.)

In most cases, significantly elevated fasting plasma glucose levels (ie, >140 mg/dL or >7.77 nmol/L; hyperglycemia) are,
in themselves, usually diagnostic of diabetes. However, mild, borderline cases may present with normal fasting glucose
values. If diabetes is suspected, a GTT can confirm the diagnosis. Occasionally, other diseases may produce elevated
plasma glucose levels; therefore, a comprehensive history, physical examination, and workup should be done before a
definitive diagnosis of diabetes is established.

Clinical Alert
A. New NIH guidelines endorse diabetic testing of all adults = 45 years every 3 years. The American Diabetes
Association recommends the following guidelines for testing:
1. Testing should be considered if patient is >45 years of age.
2. Testing is strongly recommended if patient is >45 years of age and overweight.
3. Testing should be considered if patient is <45 years of age and overweight with another risk factor.
B. Diabetes mellitus, a group of metabolic disorders, is characterized by hyperglycemia and abnormal protein, fat,
and carbohydrate metabolism due to defects in insulin secretions, ie, inadequate and deficient insulin action on
target organs, or both.
C. 1.Symptoms of diabetes plus random/casual plasma glucose concentration =200 mg/dL (11.1 mmol/L).
Random/casual is defined as any time of day without regard to time since last meal. The classic symptoms of
diabetes include polyuria, polydipsia, and unexplained weight loss.
2. or FPG =126 mg/dL (7.0 mmol/L). Fasting is defined as no caloric intake for at least 8 h.
3. or 2-h PG =200 mg/dL (11.1 mmol/L) during an OGTT. The test should be performed as described by WHO,
using a glucose load containing the equivalent of 75 g anhydrous glucose dissolved in water.
Footnote
In the absence of unequivalent hyperglycemia with acute, metabolic decompensation, these criteria should be confirmed by repeat testing on a
different day. OGTT is not recommended for routine clinical use. Source: Diabetes Care 25: 742–749, 2000.

Reference Values

Normal Fasting adults: =110 mg/dL or =6.1 nmol/L Fasting children (2–18 years): 60–100 mg/dL or 3.3–5.6 mmol/L
Fasting young children (0–2 years): 60–110 mg/dL or 3.3–6.1 mmol/L Fasting premature infants: 40–65 mg/dL or 2.2–3.6
mmol/L
Procedure
1. Draw a 5-mL venous blood sample from a fasting person. In known cases of diabetes, blood drawing should
precede insulin or oral hypoglycemic administration. Observe standard precautions. Serum is acceptable if
separated from red cells within an hour. A gray-topped tube, which contains sodium chloride, is acceptable for 24
hours without separation.
2. Be aware that self-monitoring of blood glucose by the person with diabetes can be done by finger-stick blood drop
sampling several times per day if necessary. Several devices are commercially available for this procedure; they
are relatively easy to use and have been established as a major component in satisfactory diabetes control.
Calibration of monitoring devices should be done on a regular basis.
3. Be aware that noninvasive methods using skin pads to check blood glucose level are being developed for
self-monitoring that eliminate the dreaded finger-prick test, for example, a Gluco-watch (Cygnes, Redwood City,
CA), worn on the wrist and powered by an AAA battery.

NOTE
When whole blood glucose values are not equivalent to plasma values, plasma values are about 10–15% higher than
whole blood values. However, some of the newer meters now convert the whole blood values to plasma, thus giving a
better comparison between the lab values and bedside or home testing.
Patient Checklist for Self-Monitoring of Blood Glucose (SMBG) Testing This list is a general outline. Each brand of
meter has its own instructions. Read the instructions on each new meter carefully to get accurate results. Know whether
your monitor and strips give whole blood or plasma results.
1. General instructions
a. Make sure your hands are clean, dry, and warm.
b. Prick your finger with the lancet.
c. Squeeze out a drop of capillary blood.
d. Drop the blood onto the test strip or sensor.
e. Wait for the test strip or sensor to develop.
f. Compare the test strip to the chart or insert it in the meter.
g. Safely dispose of your lancet in an approved sharps container.
h. Record blood glucose results with date and time.
2. If you have type 1 diabetes mellitus, you should also monitor your urine for ketones to alert you to possibly
dangerous complications such as diabetic ketoacidosis (eg, during stress or acute illness).
3. Test more often on days when you are ill, when your blood glucose is too high, when your meal or exercise plan
changes, when you travel, or if you feel that your blood glucose is low.
4. If you do not feel you are getting accurate results, talk to your diabetes educator and/or contact the manufacturer of
your meter. Make sure you are using the meter properly.
5. Several blood glucose meters currently available are approved by the U.S. Food and Drug Administration (FDA),
the agency that approves medical devices, for what's called “alternate site testing.”
6. Alternate sites (other than fingertips) include forearm, bicep area, palm of hand, between fingers, and sometimes
the calf.
7. Tips for using alternate sites:
a. Rub the site you will use to check your blood glucose vigorously before you prick your skin. This increases
blood flow to the site.
b. Use one type of meter. Do not alternate between different meters. This will help you get consistent results.
c. Consistently use the same alternate site. For example, always use your forearms. This will help you get
consistent results.

FIGURE 6.2 Portable blood glucose analyzer (Source: HemoCue, Mission Viejo, California, USA.)
Clinical Implications
1. Elevated blood glucose (hyperglycemia) occurs in the following conditions:
a. Diabetes mellitus: a fasting glucose of >126 mg/dL (>7.0 mmol/L) or a 2-hour postprandial load plasma glucose

2.

3.

4.
5.
6.

>200 mg/dL (>11.1 mmol/L) during an oral GTT.
b. Other conditions that produce elevated blood plasma glucose levels include the following:
1. Cushing's disease (increased glucocorticoids cause elevated blood sugar levels)
2. Acute emotional or physical stress situations (eg, myocardial infarction [MI], cerebrovascular accident,
convulsions)
3. Pheochromocytoma, acromegaly, gigantism
4. Pituitary adenoma (increased secretion or growth hormone causes elevated blood glucose levels)
5. Hemochromatosis
6. Pancreatitis (acute and chronic), neoplasms of pancreas
7. Glucagonoma
8. Advanced liver disease
9. Chronic renal disease
10. Vitamin B deficiency: Wernicke's encephalopathy
11. Pregnancy (may signal potential for onset of diabetes later in life)
Decreased blood plasma glucose (hypoglycemia) occurs in the following conditions:
a. Pancreatic islet cell carcinoma (insulinomas)
b. Extrapancreatic stomach tumors (carcinoma)
c. Addison's disease (adrenal insufficiency), carcinoma of adrenal gland
d. Hypopituitarism, hypothyroid, ACTH deficiency
e. Starvation, malabsorption (starvation does not cause hypoglycemia in normal persons)
f. Liver damage (alcoholism, chloroform poisoning, arsenic poisoning)
g. Premature infant; infant delivered to a mother with diabetes
h. Enzyme-deficiency diseases (eg, galactosemia, inherited maple syrup disease, von Gierke's syndrome)
i. Insulin overdose (accidental or deliberate)
j. Reactive hypoglycemia, including alimentary hyperinsulinism, pre-diabetes, endocrine deficiency
k. Postprandial hypoglycemia may occur after GI surgery and is described with hereditary fructose intolerance,
galactosemia, and leucine sensitivity.
According to the ADA criteria, there are three definitive tests for diabetes:
a. Symptoms of diabetes plus a random/casual plasma glucose >200 mg/dL (>11.1 mmol/L), or
b. A fasting plasma glucose >126 mg/dL (>6.99 mmol/L), or
c. An oral glucose tolerance test with a 2-hour postload (75-g glucose load) level >200 mg/dL (>11.1 mmol/L)
Using any of the three methods, the criterion must be reconfirmed on a subsequent day.
The classification of diabetes diagnosis reflects a shift to the etiology or pathology of the disease from a
classification based on pharmacological treatment.
Impaired fasting glucose (IFG) or impaired glucose tolerance (IGT) is referred to as pre-diabetes. See Figure 6.1.

Interfering Factors
1. Elevated glucose:
a. Steroids, diuretics, other drugs (see Appendix J)
b. Pregnancy (a slight blood glucose elevation normally occurs)
c. Surgical procedures and anesthesia
d. Obesity or sedentary lifestyle
e. Parenteral glucose administration (eg, from total parenteral nutrition)
f. IV glucose (recent or current)
g. Heavy smoking
2. Decreased glucose:
a. Hematocrit >55%
b. Intense exercise
c. Toxic doses of aspirin, salicylates, and acetaminophen
d. Other drugs, including ethanol, quinine, and haloperidol
Interventions
Pretest Patient Care
1. Explain test purpose and blood-drawing procedure.
2. Tell patient that the test requires at least an overnight fast; water is permitted. Instruct the patient to defer insulin or
oral hypoglycemics until after blood is drawn, unless specifically instructed to do otherwise.
3. Note the last time the patient ate in the record and on the laboratory requisition.
4. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Tell the patient that he or she may eat and drink after blood is drawn.
2. Interpret test results and monitor appropriately for hyperglycemia and hypoglycemia. Counsel regarding necessary
lifestyle changes (eg, diet, exercise, glucose monitoring, medication).
3. Give the patient the following checklist:
a. Take special care of your feet.
b. Use a lubricant or unscented hand cream on dry, scaly skin.
c. Look for calluses on your soles. Rub them gently with a pumice stone.
d. Make sure new shoes fit properly; wear freshly washed socks or stockings.
e. Never go barefoot.
f. Avoid using hot water bottles, tubs of hot water, or heating pads on your feet.
g. Trim your toenails straight across.
h. Make sure your doctor inspects your feet as part of every visit.
i. Use a team approach to help you make decisions about your care. The team may include your doctor, a nurse

diabetes educator, a dietitian, your pharmacist, and your family.
j. Use other health professionals to help with your care. These may include an eye doctor (ophthalmologist or
optometrist), an exercise physiologist, a podiatrist (a foot specialist), and a psychologist.
k. Follow the most healthful lifestyle you can.
4. Persons with glucose levels >200 mg/dL (>11.1 mmol/L) should be placed on a strict intake and output program.
5. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Clinical Alert
1. If a person with known or suspected diabetes experiences headaches, irritability, dizziness, weakness, fainting,
or impaired cognition, a blood glucose test or finger-stick test must be done before giving insulin. Similar
symptoms may be present for both hypoglycemia and hyperglycemia. If a blood glucose level cannot be obtained
and one is uncertain regarding the situation, glucose may be given in the form of orange juice, sugar-containing
soda, or candy (eg, Life-Savers or jelly beans). Make certain the person is sufficiently conscious to manage
eating or swallowing. In the acute care setting, IV glucose may be given in the event of severe hypoglycemia. A
glucose gel is also commercially available and may be rubbed on the inside of the mouth by another person if the
person with diabetes is unable to swallow or to respond properly. Instruct persons prone to hypoglycemia to carry
sugar-type items on their person and to wear a necklace or bracelet that identifies the person as diabetic.
2. Frequent blood glucose monitoring, including self-monitoring, allows better control and management of diabetes
than urine glucose monitoring.
3. When blood glucose values are > 300 mg/dL (>16.6 mmol/L), urine output increases, as does the risk for
dehydration.
4. Panic values/critical values for fasting blood glucose: <40 mg/dL (<2.22 mmol/L) may cause brain damage
(women and children), <50 mg/dL (<2.77 mmol/L) (men); >400 mg/dL (>22.2 mmol/L) may cause coma
5. Diabetes is a “disease of the moment”: persons living with diabetes are continually affected by fluctuations in
blood glucose levels and must learn to manage and adapt their lifestyle within this framework. For some,
adaptation is relatively straightforward; for others, especially those identified as being “brittle,” lifestyle changes
and management are more complicated, and these patients require constant vigilance, attention, encouragement,
and support.
6. Each person with diabetes may experience certain symptoms in his or her own unique way and in a unique
pattern.

Clinical Alert
1. Infants with tremor, convulsion, or respiratory distress should have STAT glucose done, particularly in the
presence of maternal diabetes, or with hemolytic disease of the newborn.
2. Newborns that are too small or too large for gestational age should have glucose level measured in the first day
of life.
3. Diseases related to neonatal hypoglycemia:
a. Glycogen storage diseases
b. Galactosemia
c. Hereditary fructose intolerance
d. Ketogenic hypoglycemia of infancy
e. Carnitine deficiency (Reye's syndrome)
Gestational Diabetes Mellitus (GDM); O'Sullivan Test (1-h Gestational Diabetes Mellitus Screen)
Glucose intolerance during pregnancy (gestational diabetes mellitus [GDM]) is associated with an increase in perinatal
morbidity and mortality, especially in women who are aged >25 years, overweight, or hypertensive. Additionally, more
than one half of all pregnant patients with an abnormal GTT do not have any of the same risk factors. It is therefore
recommended that all pregnant women be screened for gestational diabetes.
The O'Sullivan test, based on an OGTT, is done to detect gestational diabetes and screen nonsymptomatic pregnant
women. During pregnancy, abnormal carbohydrate metabolism is evaluated by screening all pregnant women at first
prenatal visit, then again at 24 to 28 weeks.
One-step approach: An oral glucose load of 50 g is administered, and blood is examined for glucose levels 1 hour after
administration. Women with a family history of diabetes or previous gestational diabetes should undergo the O'Sullivan
test at 15 to 19 weeks of gestation and again at 24 to 28 weeks of gestation.
Two-step approach: Measure plasma or serum glucose 1 hour after GTT (glucose challenge).
Reference Values
Normal 130–140 mg/dL or 7.2–7.9 mmol/L (1 hour after 50 g of glucose)
Procedure
1. Draw a 5-mL venous blood sample (sodium fluoride) after 8–14 hour fast, at least 3 days of unrestricted diet and
activity and after glucose load.
2. Observe standard precautions. Place specimen in a biohazard bag.
Clinical Implications
1. Abnormal GDM test result is after 100 g glucose load and after 75 g glucose load reveals glucose intolerance.
2. A 3-hour gestational GTT must then be done.

3. A positive result in a pregnant woman means she is at much greater risk (7 times) for having gestational diabetes
mellitus (GDM).
4. GDM is any degree of glucose intolerance with onset during pregnancy or first recognized pregnancy.
Interventions
Pretest Patient Care
1. Explain test purpose (to evaluate abnormal carbohydrate metabolism and predict diabetes in later life) and
procedure. No fasting is usually required. Obtain pertinent history of diabetes and record any signs or symptoms of
diabetes.
2. Instruct the woman about obtaining a urine sample for glucose testing to check before drinking the glucose load.
Positive urine glucose should be checked with the physician before glucose load. Those with glycosuria >250
mg/dL (>13.8 mmol/L) must have a blood glucose test before O'Sullivan or GDM testing.
3. Give the patient 75–100 g of glucose beverage (150 mL dissolved in water, or Trutol or Orange DEX).
4. Explain to the patient that no eating, drinking, smoking, or gum chewing is allowed during the test. The patient
should not leave the office. She may void if necessary.
5. After 1 hour, draw one NaFl or EDTA tube (5-mL venous blood) using standard venipuncture technique. If a 75 g
glucose is given, also collect a 2-hour specimen. If a 100 g glucose load is given, obtain 2- and 3-hour specimens.
Posttest Patient Aftercare
1.
2.
3.
4.

Normal activities, eating, and drinking may be resumed.
Interpret test results and explain to patient that a normal outcome is <140 mg/dL (<7.8 mmol/L).
A follow-up 3-hour gestational GTT or OGTT is indicated for all abnormal screenings.
Six weeks after delivery, the patient should be retested and reclassified. In most cases, glucose will return to
normal.

Glucose Tolerance Test (GTT); Oral Glucose Tolerance Test (OGTT)
In a healthy individual, the insulin response to a large oral glucose dose is almost immediate. It peaks in 30 to 60 minutes
and returns to normal levels within 3 hours when sufficient insulin is present to metabolize the glucose ingested at the
beginning of the test. The test should be performed according to WHO guidelines using glucose load containing the
equivalent of 75–100 g of anhydrous glucose dissolved in water or other solution.
If fasting and postload glucose test results are borderline, the GTT can support or rule out a diagnosis of diabetes
mellitus; it can also be a part of a workup for unexplained hypertriglyceridemia, neuropathy, impotence, renal diseases,
or retinopathy. This test may be ordered when there is sugar in the urine or when the fasting blood sugar level is
significantly elevated. The GTT/OGTT should not be used as a screening test for nonpregnant adults or children.
Indications for Test The GTT/OGTT should be done on certain patients, particularly those with the following indications
(few indications still meet wide acceptance):
1.
2.
3.
4.
5.

Family history of diabetes
Obesity
Unexplained episodes of hypoglycemia
History of recurrent infections (boils and abscesses)
In women, history of delivery of large infants, stillbirths, neonatal death, premature labor, and spontaneous
abortions
6. Transitory glycosuria or hyperglycemia during pregnancy, surgery, trauma, stress, MI, and ACTH administration
Reference Values
Normal Fasting plasma glucose (PG): Adults: 110 mg/dL or 6.1 mmol/L 30-minute: Adults: 110–170 mg/dL or 6.1–9.4
mmol/L 60-minute (1-hour) plasma glucose (PG) after glucose load: Adults: <184 mg/dL or <10.2 mmol/L 120-minute
(2-hour GTT test) 2-hour plasma glucose (PG) after glucose load: Adults: <138 mg/dL or <7.7 mmol/L Children:
<140 mg/dL or <7.8 mmol/L 3-hour plasma glucose (PG) after glucose load: Adults: 70–120 mg/L or 3.9–6.7 mmol/L All
four blood values must be within normal limits to be considered normal.
Procedure This is a timed test for glucose tolerance. A 2-hour plasma glucose test is done after glucose load to detect
diabetes in individuals other than pregnant women; the 3-hour test is done for pregnant women; and the 4-hour test
evaluates possible hypoglycemia.
1. Have patient eat a diet of >150 g of carbohydrates for 3 days before the test.
2. Ensure that the following drugs are discontinued 3 days before the test because they may influence test results:
a. Hormones, oral contraceptives, steroids
b. Salicylates, anti-inflammatory drugs
c. Diuretic agents
d. Hypoglycemic agents
e. Antihypertensive drugs
f. Anticonvulsants (see Appendix J)
3. Insulin and oral hypoglycemics should be withheld until the test is completed.
4. Record the patient's weight.
a. Pediatric doses of glucose are based on body weight, calculated as 1.75 g/kg not to exceed a total of 75 g.
b. Pregnant women: 100 g glucose
c. Nonpregnant adults: 75 g glucose
d. Possible gestational diabetes: 100 g glucose
5. A 5-mL sample of venous blood is drawn. Serum or gray-topped tubes are used. The patient should fast 12 to 16

6.
7.
8.
9.

10.

hours before testing. After the blood is drawn, the patient drinks all of a specially formulated glucose solution within
a 5-minute time frame.
Blood samples are obtained 30 minutes, 1 hour, 2 hours, and 3 hours after glucose ingestion.
Specimens taken 4 hours after ingestion are significant for detecting hypoglycemia and may be ordered (5-hour
specimens have been discredited).
Tolerance tests can also be performed for pentose, lactose, galactose, and d-xylose.
The GTT is not indicated in these situations:
a. Persistent fasting hyperglycemia >140 mg/dL or >7.8 mmol/L
b. Persistent fasting normal plasma glucose
c. Patients with overt diabetes mellitus
d. Persistent 2-hour plasma glucose >200 mg/dL or >11.1 mmol/L
Test has limited value in diagnosis of diabetes mellitus in children and is rarely indicated for that purpose.

Clinical Implications
1. The presence of abnormal GTT values (decreased tolerance to glucose) is based on the International Classification
for Diabetes Mellitus and the following glucose intolerance categories:
a. At least two GTT values must be abnormal for a diagnosis of diabetes mellitus to be validated.
b. In cases of overt diabetes, no insulin is secreted; abnormally high glucose levels persist throughout the test.
c. Glucose values that fall above normal values but below the diagnostic criteria for diabetes or impaired glucose
tolerance (IGT) should be considered nondiagnostic.
2. See Table 6.3 for an interpretation of glucose tolerance levels.
Table 6.3 Glucose Tolerance Test (GTT) Levels

Fasting adult
Adult diabetes mellitus 1-h glucose
and 2-h glucose
Fasting adult
Adult impaired glucose tolerance 1-h glucose
and 2-h glucose
Juvenile diabetes mellitus (fasting glucose)
and 1-h glucose
and 2-h glucose
Impaired glucose tolerance in children (fasting glucose)
and 2-h glucose

Conventional
Units (mg/dL)

SI Units
(mmol/L)

140
>200
>200
140
>200
>140–200
>140
>200
>200

>7.8
>11.1
>11.1
7.8
>11.1
>7.8–11.1
>7.8
>11.1
>11.1

>140

>7.8

3. A diagnosis of gestational diabetes mellitus (GDM) is based on the following blood glucose results (more than two
tests must be met and exceeded): fasting, >95 mg/dL (>5.3 mmol/L); 1-hour, >180 mg/dL (>10.8 mmol/L); 2-hour,
>155 mg/dL (>8.6 mmol/L); and 3-hour, >140 mg/dL (>7.8 mmol/L).
a. All pregnant women should be tested for gestational diabetes with a 50-g dose of glucose at 24 to 28 weeks of
gestation. Pregnant women with abnormal GTT are at risk for preeclampsia/eclampsia and delivery of a large
infant.
b. If abnormal results occur during pregnancy, repeat GTT at the first postpartum visit.
c. During labor, maintain maternal glucose levels at 80 to 100 mg/dL (4.4–5.5 mmol/L); beware of markedly
increased insulin sensitivity in the immediate postpartum period.
4. Decreased glucose tolerance occurs with high glucose values in the following conditions:
a. Diabetes mellitus
b. Postgastrectomy
c. Hyperthyroidism
d. Excess glucose ingestion
e. Hyperlipidemia types III, IV, and V
f. Hemochromatosis
g. Cushing's disease (steroid effect)
h. CNS lesions
i. Pheochromocytoma
5. Decreased glucose tolerance with hypoglycemia can be found in persons with von Gierke's disease, severe liver
damage, or increased epinephrine levels.
6. Increased glucose tolerance with flat curve (ie, glucose does not increase, but may decrease to hypoglycemic
levels) occurs in the following conditions:
a. Pancreatic islet cell hyperplasia or tumor
b. Poor intestinal absorption caused by diseases such as sprue, celiac disease, or Whipple's disease
c. Hypoparathyroidism
d. Addison's disease
e. Liver disease
f. Hypopituitarism, hypothyroidism
Interfering Factors
1. Smoking increases glucose levels.
2. Altered diets (eg, weight reduction) before testing can diminish carbohydrate tolerance and suggest “false

3.
4.
5.
6.

7.

diabetes.”
Glucose levels normally tend to increase with aging.
Prolonged oral contraceptive use causes significantly higher glucose levels in the second hour or in later blood
specimens.
Infectious diseases, illnesses, and operative procedures affect glucose tolerance. Two weeks of recovery should be
allowed before performing the test.
Certain drugs impair glucose tolerance levels (this list is not all inclusive; see Appendix J for other drugs):
a. Insulin
b. Oral hypoglycemics
c. Large doses of salicylates, anti-inflammatories
d. Thiazide diuretics
e. Oral contraceptives
f. Corticosteroids
g. Estrogens
h. Heparin
i. Nicotinic acid
j. Phenothiazines
k. Lithium
l. Metyrapone (Metopirone) If possible, these drugs should be discontinued for at least 3 days before testing.
Check with clinician for specific orders.
Prolonged bed rest influences glucose tolerance results. If possible, the patient should be ambulatory. A GTT in a
hospitalized patient has limited value.

Interventions
Pretest Patient Care
1. Explain test purpose and procedure. A written reminder may be helpful.
a. A diet high in carbohydrates (150 g) should be eaten for 3 days preceding the test. Instruct the patient to abstain
from alcohol.
b. The patient should fast for at least 12 hours but not more than 16 hours before the test. Only water may be
ingested during fasting time and test time. Use of tobacco products is not permitted during testing.
c. Patients should rest or walk quietly during the test period. They may feel weak, faint, or nauseated during the
test. Vigorous exercise alters glucose values and should be avoided during testing.
2. Collect blood specimens at the prescribed times and record exact times collected. Urine glucose testing is no
longer recommended.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have the patient resume normal diet and activities at the end of the test. Encourage eating complex carbohydrates
and protein if permitted.
2. Administer prescribed insulin or oral hypoglycemics when the test is done. Arrange for the patient to eat within a
short time (30 minutes) after these medications are taken.
3. Interpret test results and counsel appropriately. Patients newly diagnosed with diabetes will need diet, medication,
and lifestyle modification instructions.
4. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Clinical Alert
1. GTT is contraindicated in patients with a recent history of surgery, MI, or labor and delivery; these conditions can
produce invalid values.
2. If fasting glucose is >140 mg/dL (>7.8 mmol/L) on two separate occasions, or if the 2-hour postprandial blood
glucose is >200 mg/dL (>11.1 mmol/L) on two separate occasions, GTT is not necessary for a diagnosis of
diabetes mellitus to be established.
3. The GTT is of limited diagnostic value for children.
4. The GTT should be postponed if the patient becomes ill, even with common illnesses such as the flu or a severe
cold.
5. Record and report any reactions during the test. Weakness, faintness, and sweating may occur between the
second and third hours of the test. If this occurs, a blood sample for a glucose level should be drawn immediately
and the GTT aborted.
6. Should the patient vomit the glucose solution, the test is declared invalid; it can be repeated in 3 days (˜72
hours).
Glycosylated Hemoglobin (Hb A 1c); Glycohemoglobin (G-Hb); Glycated Hemoglobin (GhB); Diabetic Control
Index; Glycated Serum Protein (GSP), Fructosamine
Glycohemoglobin is a normal, minor type of hemoglobin. Glycosylated hemoglobin is formed at a rate proportional to the
average glucose concentration by a slow, nonenzymatic process within the red blood cells (RBCs) during their 120-day
circulating life span. Glycohemoglobin is blood glucose bound to hemoglobin. In the presence of hyperglycemia, an
increase in glycohemoglobin causes an increase in Hb A 1c . If the glucose concentration increases because of insulin
deficiency, then glycosylation is irreversible.
Glycosylated hemoglobin values reflect average blood sugar levels for the 2- to 3-month period before the test. This test
provides information for evaluating diabetic treatment modalities (every 3 months), is useful in determining treatment for

juvenile-onset diabetes with acute ketoacidosis, and tracks control of blood glucose in milder cases of diabetes. It can be
a valuable adjunct in determining which therapeutic choices and directions (eg, oral antihypoglycemic agents, insulin,
ß-cell transplantations) will be most effective. A blood sample can be drawn at any time. The measurement is of particular
value for specific groups of patients: diabetic children, diabetic patients in whom the renal threshold for glucose is
abnormal, unstable type 1 diabetic patients (taking insulin) in whom blood sugar levels vary markedly from day to day,
type 2 diabetic patients who become pregnant, and persons who, before their scheduled appointments, change their
usual habits, dietary or otherwise, so that their metabolic control appears better than it actually is.
Reference Values
Normal Results are expressed as percentage of total hemoglobin. Values vary slightly be method and laboratory. G-Hb:
4.0%–7.0% Hb A 1c: 4.0%–6.7% of total hemoglobin H
Procedure
1. Obtain a 5-mL venous blood sample with EDTA purple-topped anticoagulant additive. Serum may not be used.
2. Observe standard precautions. Place specimen in a biohazard bag.
Clinical Implications
1. Values are frequently increased in persons with poorly controlled or newly diagnosed diabetes.
2. With optimal control, the Hb A 1c moves toward normal levels.
3. A diabetic patient who recently comes under good control may still show higher concentrations of glycosylated
hemoglobin. This level declines gradually over several months as nearly normal glycosylated hemoglobin replaces
older RBCs with higher concentrations.
4. Increases in glycosylated hemoglobin occur in the following conditions:
a. Iron-deficiency anemia
b. Splenectomy
c. Alcohol toxicity
d. Lead toxicity
5. Decreases in glycosylated hemoglobin occur in the following conditions:
a. Hemolytic anemia
b. Chronic blood loss
c. Pregnancy
d. Chronic renal failure
Interfering Factors
1. Presence of Hb F and H causes falsely elevated values.
2. Presence of Hb S, C, E, D, G, and Lepore causes falsely decreased values.
Interventions
Pretest Patient Care
1. Explain test purpose and blood-drawing procedure. Observe standard precautions. Fasting is not required.
2. Note that this test is not meant for short-term diabetes mellitus management; instead, it assesses the efficacy of
long-term management modalities over several weeks or months. It is not useful more often than 4–6 weeks.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome and counsel patient appropriately for management of diabetes. If test results are not
consistent with clinical findings, check the patient for Hb F, which elevates Hb A 1c results.
2. Follow guidelines in Chapter 1 regarding safe, effective, informed posttest care.

Clinical Alert
A number of different tests can determine glycosylated hemoglobin levels. The most specific of these measures is Hb A
1c . There are different expected values for each test. Keep in mind that Hb A 1 is always 2% to 4% higher than Hb A 1c.
When interpreting results, be certain of the specific test used.
Critical Value
1. GHB: >10.1%
2. A 1c: >8.1% (corresponds with glucose >200 mg/dL or >11.1 mmol/L)
Lactose Tolerance; Breath Hydrogen Test
Lactose intolerance often begins in infancy, with symptoms of diarrhea, vomiting, failure to thrive, and malabsorption. The
patient becomes asymptomatic when lactose is removed from the diet. This syndrome is caused by a deficiency of
sugar-splitting enzymes (lactase) in the intestinal tract.
This test is actually a GTT done to diagnose intestinal disaccharidase (lactase) deficiency. Glucose is measured, and it is
the increase or lack of increase over the fasting specimen that is used for the interpretation. Breath samples reveal
increased hydrogen levels, which are caused by lactose buildup in the intestinal tract. Colonic bacteria metabolize the

lactose and produce hydrogen gas.
Reference Values
Normal Change in glucose from normal value of >30 mg/dL or >1.7 mmol/L Inconclusive: 20–30 mg/dL or 1.1–1.7
mmol/L Abnormal: <20 mg/dL or <1.1 mmol/L Hydrogen (breath): <10 ppm increase from baseline is abnormal
Procedure
1. Follow instruction given for the GTT.
2. Draw a blood specimen from a fasting patient. The patient then drinks 50 g of lactose mixed with 200 mL of water (2
g lactose/kg body weight).
3. Draw blood lactose samples at 0, 30-, 60-, and 90-minute intervals.
4. Take hydrogen breath samples at the same time intervals as the blood specimens. Contact your laboratory for
collection procedures.
Clinical Implications
1. Lactose intolerance occurs as follows:
a. A “flat” lactose tolerance finding (ie, no rise in glucose) points to a deficiency of sugar-splitting enzymes, as in
irritable bowel syndrome. This type of deficiency is more prevalent in American Indians, African Americans,
Asians, and Jews.
b. A monosaccharide tolerance test such as the glucose/galactose tolerance test should be done as a follow-up.
1. The patient ingests 25 g of both glucose and galactose.
2. A normal increase in glucose indicates a lactose deficiency.
c. Secondary lactose deficiency found in:
1. Infectious enteritis
2. Bacterial overgrowth in intestines
3. Inflammatory bowel disease, Crohn's disease
4. Giardia lamblia infestation
5. Cystic fibrosis of pancreas
d. The hydrogen breath test is abnormal in the lactose deficiency test because:
a. Malabsorption causes hydrogen (H 2) production through the process of fermentation of lactose in the colon.
b. The H 2 formed is directly proportional to the amount of test dose lactose not digested by lactase.
e. In diabetes:
a. Blood glucose values may show increases of >20 mg/dL (>1.11 mmol/L) despite impaired lactose absorption.
b. In diabetes, there may be an abnormal lactose tolerance curve due to faulty metabolism, not necessarily
from lactose intolerance.
Interventions
Pretest Patient Preparation
1.
2.
3.
4.
5.

Explain test purpose and procedure. The patient must fast for 8–12 hours before the test.
Do not allow the patient to eat dark bread, peas, beans, sugars, or high-fiber foods within 24 hours of the test.
Do not permit smoking during the test and for 8 hours before testing; no gum chewing.
Do not allow antibiotics to be taken for 2 weeks before the test unless specifically ordered.
Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Aftercare
1. Have the patient resume normal diet and activity.
2. Interpret test results and counsel appropriately. Patients with irritable bowel syndrome with gas, bloating, abdominal
pain, constipation, and diarrhea have lactose deficiency. Restricting milk intake relieves symptoms.
3. Follow guidelines in Chapter 1 regarding safe, effective, informed posttest care.

END PRODUCTS OF METABOLISM AND OTHER TESTS
Ammonia (NH 3)
Ammonia, an end product of protein metabolism, is formed by bacteria acting on intestinal proteins together with
glutamine hydrolysis in the kidneys. The liver normally removes most of this ammonia via the portal vein circulation and
converts the ammonia to urea. Because any appreciable level of ammonia in the blood affects the body's acid-base
balance and brain function, its removal from the body is essential. The liver accomplishes this by synthesizing urea so
that it can be excreted by the kidneys.
Blood ammonia levels are used to diagnose Reye's syndrome, to evaluate metabolism, and to determine the progress of
severe liver disease and its response to treatment. Blood ammonia measurements are useful in monitoring patients on
hyperalimentation therapy.
Reference Values
Normal Adults: 15–56 µg/dL or 9–33 µmol/L Children: 36–85 µg/dL or 21–50 µmol/L 10 days–2 years: (<2 weeks):
95–157 µg/dL or 56–92 µmol/L Birth–10 days: 109–182 µg/dL or 64–107 µmol/L Values test somewhat higher in capillary
blood samples. Values can vary greatly with testing method used.
Procedure
1. Obtain a 5-mL venous plasma sample from a fasting patient. A green-topped (heparin) or purple-topped (EDTA)

tube may be used. Observe standard precautions.
2. Place the sample in an iced container. The specimen must be centrifuged at 4°C. Promptly remove plasma from
cells. Perform the test within 20 minutes or freeze plasma immediately.
3. Note all antibiotics the patient is receiving; these drugs lower ammonia levels.
Clinical Implications Increased ammonia levels occur in the following conditions:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.

Reye's syndrome
Liver disease, cirrhosis
Hepatic coma (does not reflect degree of coma)
GI hemorrhage
Renal disease
HHH syndrome: hyperornithinemia, hyperammonemia, homocitrullinuria
Transient hyperammonemia of newborn
Certain inborn errors of metabolism or urea except for argininosuccinicaciduria
GI tract infection with distention and stasis
Total parenteral nutrition
Ureterosigmoidostomy

Interfering Factors
1. Ammonia levels vary with protein intake and many drugs.
2. Exercise may cause an increase in ammonia levels.
3. Ammonia levels may be increased by use of a tight tourniquet or by tightly clenching the fist while samples are
drawn.
4. Ammonia levels can rise rapidly in the blood tubes.
5. Hemolysed blood gives falsely elevated levels.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. Instruct the patient to fast (if possible) for 8 hours before the blood test. Water
is permitted.
2. Do not allow the patient to smoke for several hours before the test (raises levels).
3. Follow guidelines in Chapter 1 regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes, monitor appropriately, and begin treatment.
2. Remember that in patients with impaired liver function demonstrated by elevated ammonia levels, the blood
ammonia level can be lowered by reduced protein intake and by use of antibiotics to reduce intestinal bacteria
counts.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Clinical Alert
Ammonia should be measured in all cases of unexplained lethargy and vomiting, in encephalitis, or in any neonate with
unexplained neurologic deterioration.
Bilirubin
Bilirubin results from the breakdown of hemoglobin in the red blood cells and is a byproduct of hemolysis (ie, red blood
cell destruction). It is produced by the reticuloendothelial system. Removed from the body by the liver, which excretes it
into the bile; it gives the bile its major pigmentation. Usually, a small amount of bilirubin is found in the serum. A rise in
serum bilirubin levels occurs when there is an excessive destruction of red blood cells or when the liver is unable to
excrete the normal amounts of bilirubin produced.
There are two forms of bilirubin in the body: indirect or unconjugated bilirubin, which is protein bound, and direct or
conjugated bilirubin, which circulates freely in the blood until it reaches the liver, where it is conjugated with glucuronide
transferase and then excreted into the bile. An increase in protein-bound bilirubin (unconjugated bilirubin) is more
frequently associated with increased destruction of red blood cells (hemolysis); an increase in free-flowing bilirubin is
more likely seen in dysfunction or blockage of the liver. A routine examination measures only the total bilirubin. A normal
level of total bilirubin rules out any significant impairment of the excretory function of the liver or excessive hemolysis of
red cells. Only when total bilirubin levels are elevated will there be a call for differentiation of the bilirubin levels by
conjugated and unconjugated types.
The measurement of bilirubin allows evaluation of liver function and hemolytic anemias. This test is not suitable for
infants younger than 15 days (see Neonatal Bilirubin on page 342).
Reference Values
Normal Adults Total: 0.3–1.0 mg/dL or 5–17 µmol/L Conjugated (direct): 0.0–0.2 mg/dL or 0.0–3.4 µmol/L
Procedure

1.
2.
3.
4.

Obtain a 5-mL nonhemolyzed sample from a fasting patient. Observe standard precautions. Serum is used.
Protect the sample from ultraviolet light (sunlight).
Avoid air bubbles and unnecessary shaking of the sample during blood collection.
If the specimen cannot be examined immediately, store it away from light and in a refrigerator.

Clinical Implications
1. Total bilirubin elevations accompanied by jaundice may be due to hepatic, obstructive, or hemolytic causes.
a. Hepatocellular jaundice results from injury or disease of the parenchymal cells of the liver and can be caused by
the following conditions:
1. Viral hepatitis
2. Cirrhosis
3. Infectious mononucleosis
4. Reactions of certain drugs such as chlorpromazine
b. Obstructive jaundice is usually the result of obstruction of the common bile or hepatic ducts due to stones or
neoplasms. The obstruction produces high conjugated bilirubin levels due to bile regurgitation.
c. Hemolytic jaundice is due to overproduction of bilirubin resulting from hemolytic processes that produce high
levels of unconjugated bilirubin. Hemolytic jaundice can be found in the following conditions:
1. After blood transfusions, especially those involving many units
2. Pernicious anemia
3. Sickle cell anemia
4. Transfusion reactions (ABO or Rh incompatibility)
5. Crigler-Najjar syndrome (a severe disease that results from a genetic deficiency of a hepatic enzyme needed
for the conjugation of bilirubin)
6. Erythroblastosis fetalis (see Neonatal Bilirubin, page 342)
d. Miscellaneous diseases
1. Dubin-Johnson syndrome
2. Gilbert's disease (familial hyperbilirubinemia)
3. Nelson's disease (with acute liver failure)
4. Pulmonary embolism/infarct
5. Congestive heart failure
2. Elevated indirect unconjugated bilirubin levels occur in the following conditions:
a. Hemolytic anemias due to a large hematoma
b. Trauma in the presence of a large hematoma
c. Hemorrhagic pulmonary infarcts
d. Crigler-Najjar syndrome (rare)
e. Gilbert's disease (conjugated hyperbilirubinemia; rare)
3. Elevated direct conjugated bilirubin levels occur in the following conditions:
a. Cancer of the head of the pancreas
b. Choledocholithiasis
c. Dubin-Johnson syndrome
Interfering Factors
1. A 1-hour exposure of the specimen to sunlight or high-intensity artificial light at room temperature will decrease the
bilirubin content.
2. No contrast media should be administered 24 hours before measurement; a high-fat meal may also cause
decreased bilirubin levels by interfering with the chemical reactions.
3. Air bubbles and shaking of the specimen may cause decreased bilirubin levels.
4. Certain foods (eg, carrots, yams) and drugs (see Appendix J) increase the yellow hue in the serum and can falsely
increase bilirubin levels when tests are done using certain methods (eg, spectrophotometer).
5. Prolonged fasting raises the bilirubin level, as does anorexia.
6. Nicotinic acid increases unconjugated bilirubin.

Clinical Alert
Panic Value for Bilirubin in Adults
>12 mg/dL or >200 µmol/L
Interventions
Pretest Patient Care
1. Explain test purpose and procedure and relation of results to jaundice.
2. Ensure that the patient is fasting, if possible.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

NOTE
Excessive amounts of bilirubin eventually seep into the tissues, which assume a yellow hue as a result. This yellow
color is a clinical sign of jaundice. In newborns, signs of jaundice may indicate hemolytic anemia or congenital icterus.
Total bilirubin must be >2.5 mg/dL (>41.6 µmol/L) to detect jaundice in adults.
Posttest Patient Aftercare

1. Interpret test outcome and monitor appropriately.
2. Have patient resume normal activities.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Neonatal Bilirubin, Total and Fractionated (“Baby Bili”)
In newborns, signs of jaundice may indicate hemolytic anemia or congenital icterus. If bilirubin levels reach a critical point
in the infant, damage to the CNS may occur in a condition known as kernicterus. Therefore, in these infants, the level of
bilirubin is the deciding factor in whether or not to perform an exchange transfusion. Total bilirubin must be >5.0 mg/dL to
detect jaundice in newborns.
Jaundice may also be seen in babies who are breast feeding as a result of low milk intake and subsequent lack of vitamin
K–dependent clotting factors. This condition usually resolves within 1 week.
Neonatal bilirubin is used to monitor erythroblastosis fetalis (hemolytic disease of the newborn), which usually causes
jaundice in the first 2 days of life. All other causes of neonatal jaundice, including physiologic jaundice,
hematoma/hemorrhage, liver disease, and biliary disease, should also be monitored. Normal, full-term neonates
experience a normal, neonatal, physiologic, transient hyperbilirubinemia by the third day of life, which rapidly falls by the
fifth to tenth day of life. This test cannot be used after the tenth day of life owing to the formation of endogenous
carotenoids.
Reference Values
Normal Newborns (0–7 days) Total: 1.0–10.0 mg/dL or 17–170 µmol/L Conjugated (direct): 0.0–0.8 mg/dL or 0–136
µmol/L Unconjugated (indirect): 0.0–10.0 mg/dL or 0–170 µmol/L Cord blood total: Full term: <2.5 mg/dL or <43 µmol/L
Premature: <2.9 mg/dL or <50 µmol/L See Table 6.4 for a comparison of premature and full-term infants.
Table 6.4 Neonatal Total Comparison
Premature (mg/dL) SI Units (µmol/L) Full Term (mg/dL) SI Units (µmol/L)
<24 h: <8.0
<137
<6.0
<103
<48 h: <12.0
<205
<10.0
<170
3–5 day: <15.0
<256
<12.0
<205
7 day: <15.0
<256
<10.0
<170
Note: Most labs are not doing conjugated and unconjugated anymore.

Procedure
1. Draw blood from heel of newborn using a capillary pipette and amber Microtainer tube; 0.5 mL of serum is needed.
Cord blood may also be used.
2. Protect sample from light.
Clinical Implications
1. Elevated total bilirubin (neonatal) is associated with the following conditions:
a. Erythroblastosis fetalis occurs as a result of blood incompatibility between mother and fetus.
1. Rh (D) antibodies and other Rh factors
2. ABO antibodies
3. Other blood groups, including KIDD, KELL, and DUFFY (see Chapter 8)
b. Galactosemia
c. Sepsis
d. Infectious diseases (eg, syphilis, toxoplasmosis, cytomegalovirus)
e. Red blood cell enzyme abnormalities
1. Glucose-6-phosphate dehydrogenase (G6PD) deficiency
2. Pyruvate kinase (PK) deficiency
3. Spherocytosis
f. Subdural hematoma, hemangiomas
2. Elevated unconjugated (indirect) neonatal bilirubin is associated with the following conditions:
a. Erythroblastosis fetalis
b. Hypothyroidism
c. Crigler-Najjar syndrome
d. Obstructive jaundice
e. Infants of diabetic mothers
3. Elevated conjugated (direct) neonatal bilirubin is associated with the following conditions:
a. Biliary obstruction
b. Neonatal hepatitis
c. Sepsis

Clinical Alert
Panic Value for Neonatal Bilirubin
>15 mg/dL or >256 µmol/L (mental retardation can occur)
Interventions
Pretest Patient Care
1. Explain test purpose and procedure and its relation to jaundice to the mother.
2. See Chapter 1 guidelines for safe, informed, effective pretest care.
Posttest Patient Aftercare
1. Interpret test outcome and monitor appropriately.
2. Be aware that for slight elevations (ie, <10.0 mg/dL or <170 µmol/L), phototherapy may be initiated.
3. Monitor neonatal bilirubin levels to determine indication for exchange transfusion. Tests should be done every 12
hours in jaundiced newborns. See Table 6.5 for exchange transfusion indications.
Table 6.5 Indications for Exchange Transfusion
Birth Weight (g)

Serum Bilirubin (mg/dL)

Serum Bilirubin (µmol/L)

<1000
1001–1250
1251–1500
1501–2000
2001–2500
>2500

10.0
13.0
15.0
17.0
18.0
20.0

170
222
256
291
309
>342

4. Transfuse at one step earlier in the presence of the following conditions:
a. Coombs' test positive
b. Serum protein <5 g/dL
c. Metabolic acidosis (pH < 7.25)
d. Respiratory distress (with O 2 <50 mm Hg or 6.6 kPA)
e. Certain clinical findings (eg, hypothermia, CNS, or other clinical deterioration; sepsis; hemolysis)
Other criteria for exchange transfusion are suddenness and rate of bilirubin increase and when such an increase occurs;
for example, an increase of 3 mg/dL (51 µmol/L) in 12 hours, especially after bilirubin has already leveled off, must be
followed by frequent serial determinations, especially if it occurs on the first or seventh day of life rather than on the third
day. Beware of a rate of bilirubin increase of >1 mg/dL (>17 µmol/L) during the first day of life. Serum bilirubin of 10
mg/dL (170 µmol/L) after 24 hours or 15 mg/dL (256 µmol/L) after 48 hours despite phototherapy usually indicates that
serum bilirubin will reach 20 mg/dL (342 µmol/L).
Blood Urea Nitrogen (BUN, Urea Nitrogen)
Urea forms in the liver and, along with CO 2 , constitutes the final product of protein metabolism. The amount of excreted
urea varies directly with dietary protein intake, increased excretion in fever, diabetes, and increased adrenal gland
activity.
The test for BUN, which measures the nitrogen portion of urea, is used as an index of glomerular function in the
production and excretion of urea. Rapid protein catabolism and impairment of kidney function will result in an elevated
BUN level. The rate at which the BUN level rises is influenced by the degree of tissue necrosis, protein catabolism, and
the rate at which the kidneys excrete the urea nitrogen. A markedly increased BUN is conclusive evidence of severe
impaired glomerular function. In chronic renal disease, the BUN level correlates better with symptoms of uremia than
does the serum creatinine.
Reference Values
Normal Adults: 6–20 mg/dL or 2.1–7.1 mmol/L Elderly patients (>60 years): 8–23 mg/dL or 2.9–8.2 mmol/L Children:
5–18 mg/dL or 1.8–6.4 mmol/L
Procedure
1. Obtain a 5-mL venous blood sample. Serum is preferred.
2. Observe standard precautions.
Clinical Implications
1. Increased BUN levels (azotemia) occur in the following conditions:
a. Impaired renal function caused by the following conditions:
1. Congestive heart failure
2. Salt and water depletion
3. Shock
4. Stress
5. Acute MI

b. Chronic renal disease such as glomerulonephritis and pyelonephritis
c. Urinary tract obstruction
d. Hemorrhage into GI tract
e. Diabetes mellitus with ketoacidosis
f. Excessive protein intake or protein catabolism as occurs in burns or cancer
g. Anabolic steroid use
2. Decreased BUN levels are associated with the following conditions:
a. Liver failure (severe liver disease), such as that resulting from hepatitis, drugs, or poisoning
b. Acromegaly
c. Malnutrition, low-protein diets
d. Impaired absorption (celiac disease)
e. Nephrotic syndrome (occasional)
f. Syndrome of inappropriate antidiuretic hormone (SIADH)
Interfering Factors
1. A combination of a low-protein and high-carbohydrate diet can cause a decreased BUN level.
2. The BUN is normally lower in children and women because they have less muscle mass than adult men.
3. Decreased BUN values normally occur in late pregnancy because of increased plasma volume (physiologic
hydremia).
4. Older persons may have an increased BUN when their kidneys are not able to concentrate urine adequately.
5. IV feedings only may result in overhydration and decreased BUN levels.
6. Many drugs may cause increased or decreased BUN levels.

Clinical Alert
1. If a patient is confused, disoriented, or has convulsions, the BUN level should be checked. If the level is high, it
may help to explain these signs and symptoms.
2. Panic value for BUN is >100 mg/dL (>35 mmol/L).
Interventions
Pretest Patient Care
1. Explain test purpose and blood-drawing procedure. Assess dietary history.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome and monitor as appropriate for impaired kidney function.
2. Be aware that in patients with an elevated BUN level, fluid and electrolyte regulation may be impaired.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Albumin
Albumin (along with total protein) is a part of a diverse microenvironment. Its primary function is the maintenance of
colloidal osmotic pressure (COP) in the vascular and extravascular spaces (eg, urine, cerebrospinal fluid, and omniotic
fluid). Albumin is a source of nutrition and also a part of a complex buffer system. It is a “negative” acute-phase reactant.
It decreases in response to acute inflammatory infectious processes.
Albumin is used to evaluate nutritional status, albumin loss in acute illness, liver disease and renal disease with
proteinuria, hemorrhage, burns, exudates or leaks in the GI tract, and other chronic diseases. Hypoalbuminuria is an
independent risk factor for older adults for mortality—admission serum albumin in geriatric patients is a predictor of
outcome.
Reference Values
Normal Children: 2.9–5.5 g/dL or 29–55 g/L Adults: 3.5–4.8 g/dL or 35–48 g/L After age 40 years and in persons living in
subtropics and tropics (secondary to parasitic infections), level slowly declines.
Procedure
1.
2.
3.
4.

Obtain 5 mL of serum in a light green tube. Fasting is not necessary.
Centrifuge within 30 minutes of blood draw. Place specimen in a biohazard bag.
Observe standard procedures.
Urine specimens may also be collected (see Chapter 3).

Clinical Implications
1. Increased albumin is not associated with any naturally occurring condition. When albumin is increased, the only
cause is decreased plasma water that increases the albumin proportionally: dehydration.
2. Decreased albumin is associated with the following conditions:
a. Acute and chronic inflammation and infections
b. Cirrhosis, liver disease, alcoholism
c. Nephrotic syndrome, renal disease (increased loss in urine)
d. Crohn's disease, colitis
e. Congenital analbuminurea
f. Burns, severe skin disease

g. Heart failure
h. Starvation, malnutrition, malabsorption, anorexia (decreased synthesis)
i. Thyroid diseases: Cushing's disease, thyrotoxicosis
Interfering Factors Albumin is decreased in:
1.
2.
3.
4.

Pregnancy (last trimester, owing to increased plasma volume)
Oral birth control (estrogens) and other drugs (see Appendix J)
Prolonged bed rest
IV fluids, rapid hydration, overhydration

Clinical Alert
Panic range: <1.5 g/dL or 15 g/L
Levels at 2.0–2.5 g/dL or 20–25 g/L may be the cause of edema.
Low levels occur with prolonged hospital stay.
Lipemic specimens with a high fat content interfere.
Interventions
Pretest Patient Care
1. Explain test purpose and specimen collection procedure. No fasting is required.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1.
2.
3.
4.

Interpret test outcome and monitor appropriately. Explain possible need for treatment (replacement therapy).
Low levels are associated with edema. Assess patient for these signs and symptoms.
Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Be aware that further tests may have to be done:
a. Total protein
b. Protein electrophoresis
c. 24-hour urine protein

Prealbumin (PAB)
In 1995, the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) first issued standards that
hospitals assess a patient's nutritional status and that all patients at risk for malnutrition be identified. Visceral proteins
most often used in nutrition assessment include albumin, prealbumin, C-reactive protein, and retinol-binding protein.
When used in combination, they can very accurately reflect a subclinical deficit and assess response to restorative
therapy.
For years albumin was the widely accepted marker for malnutrition. However, mounting evidence points to prealbumin
(PAB) as the better choice. Because albumin has a half-life of 21 days, it is slow to respond to a patient's recent increase
in nutrients and, therefore, is not a good indicator of recent changes in protein levels. In contrast, prealbumin responds
more rapidly and gives a timelier picture of a change in dietary status. Because of its short half-life (2 days), PAB
responds quickly to a decrease in nutritional intake and nutritional restoration. It reflects the current nutritional status
within a patient's body, not the status from 3 weeks ago.
Reference Values
Normal 19–38 mg/dL (190–380 mg/L) by nephelometry
Procedure
1. Collect 7-mL blood serum sample in a red-topped tube. Observe standard precautions.
2. Place specimen in a biohazard bag for transport to the laboratory.
Clinical Implications
1. Hospital laboratories, in conjunction with dieticians, administration, pharmacists, nurses, and physicians, may
develop a clinical pathway that includes running a PAB upon admission of each surgical, ICU, and medicinal
patient.
2. Values of 0–5, 5–10, and 10–15 mg/dL (0–50, 50–100, and 100–150 mg/L) indicate severe, moderate, and mild
protein depletion, respectively.
Interventions
Pretest Patient Care
1. Explain test purpose. PAB is useful in assessing nutritional status, especially in monitoring the response to
nutritional support in the acutely ill patient.
2. Follow guidelines in Chapter 1 regarding safe, effective, informed, pretest care .

Posttest Patient Aftercare
1. Interpret test outcomes and determine the need for possible follow-up testing. Hospital protocol may require
patients to be retested twice a week until discharge if their PAB level is less than 18 mg/dL (<180 mg/L). Possible
treatment includes replacement/restorative therapy.
2. Follow guidelines in Chapter 1 regarding safe, effective, informed posttest care.
Cholinesterase, Serum (Pseudocholinesterase); Cholinesterase, Red Blood Cell (Acetylcholinesterase)
The cholinesterase of serum is referred to as pseudocholinesterase to distinguish it from the true cholinesterase of the
red blood cell (RBC). Both of these enzymes act on acetylcholine and other cholinesters. Alkylphosphates are potent
inhibitors of both serum and RBC cholinesterase.
Patients who are homozygous for the atypical gene that controls serum cholinesterase activity have low levels of
cholinesterase that are not inhibited by dibucaine. Persons with normal serum cholinesterase activity show 70% to 90%
inhibition by dibucaine.
The red cell (true cholinesterase) enzyme is specific for the substrate acetylcholine.
These are two separate tests. The primary use of serum cholinesterase measurement (pseudocholinesterase) is to
monitor the effect of muscle relaxants (eg, succinylcholine), which are used in surgery. Patients for whom suxamethonium
anesthesia is planned should be tested using the dibucaine inhibition test for the presence of atypical cholinesterase
variants that are incapable of hydrolyzing this widely used muscle relaxant.
The RBC cholinesterase test is used when poisoning by pesticides such as Parathion or Malathion is suspected. Severe
insecticide poisoning causes headaches, visual distortions, nausea, vomiting, pulmonary edema, confusion, convulsions,
reparatory paralysis, and coma.
Reference Values
Normal Serum cholinesterase: 4.9–11.9 U/mL or 4.9–11.9 (× 1.00) kU/L Dibucaine inhibition: 79%–84% RBC
cholinesterase 30–40 U/g hemoglobin Values vary with substrate and method. These are two different tests. Values are
low at birth and for the first 6 months of life
Procedures
1. For serum cholinesterase, obtain a 5-mL blood sample; 3 mL of serum is needed. This is stable for 1 week at
4°–25°C. Observe standard precautions.
2. For RBC cholinesterase, draw a blood sample using sodium heparin as an anticoagulant; do not use serum.
Observe standard precautions. This is stable for 1 week at 4°–25°C.
Clinical Implications
1. Decreased or no serum cholinesterase occurs in the following conditions:
a. Congenital inherited recessive disease. These patients are not able to hydrolyze drugs such as muscle
relaxants used in surgery. These patients may have a prolonged period of apnea and may die if they are given
succinlycholine.
b. Poisoning from organic phosphate insecticides.
c. Liver diseases, hepatitis, cirrhosis with jaundice
d. Conditions that may have decreased blood albumin, such as malnutrition, anemia, infections, skin diseases, and
acute MI
e. Congestive heart failure
2. Decreased RBC cholinesterase levels occur in the following conditions:
a. Congenital inherited recessive disease
b. Organic phosphate poisoning
c. Paroxysmal nocturnal hemoglobinemia
d. Megaloblastic anemia (returns to normal with therapy)
3. Increased serum cholinesterase is associated with
a. Type IV hyperlipidemia
b. Nephrosis
c. Obesity
d. Diabetes
4. Increased RBC cholinesterase is associated with:
a. Reticulocytosis
b. Sickle cell anemia
c. Hemolytic anemias
5. Increased RBC cholinesterase in amniotic fluid, along with elevated AFP, is presumptive evidence of open neural
tube defect (not normally present in amniotic fluid)
Interventions
Pretest Patient Care
1. Explain test purpose and procedure
2. Draw blood for serum cholinesterase 2 days before surgery.
3. Be aware that blood should not be drawn in the recovery room; prior administration of surgical drugs and
anesthesia invalidates the test results.

4. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcome and counsel appropriately.
2. Consider patients exhibiting <70% inhibition as an atypical cholinesterase variant, and be aware that the
administration of succinylcholine or similar type drugs may pose a risk.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Clinical Alert
1. In industrial exposure, workers should not return to work until cholinesterase values rise to at least 75% of
normal. Red blood cell cholinesterase regenerates at the rate of 1% per day. Plasma cholinesterase regenerates
at the rate of 25% in 7 to 10 days and returns to baseline in 4 to 6 weeks.
2. Cholinesterase activity is completely and irreversibly inhibited by organophosphate pesticides.
Creatinine
Creatinine is a byproduct in the breakdown of muscle creatine phosphate resulting from energy metabolism. It is
produced at a constant rate depending on the muscle mass of the person and is removed form the body by the kidneys.
Production of creatinine is constant as long as muscle mass remains constant. A disorder of kidney function reduces
excretion of creatinine, resulting in increased blood creatinine levels. Thus, creatinine levels give an approximation of the
glomerular filtration rate.
This test diagnoses impaired renal function. It is a more specific and sensitive indicator of kidney disease than BUN,
although in chronic renal disease, both BUN and creatinine are ordered to evaluate renal problems because the
BUN/creatinine ratio provides more information.
Reference Values
Normal Adult men: 0.9–1.3 mg/dL or 80–115 µmol/L Adult women: 0.6–1.1 mg/dL or 53–97 µmol/L Children (3–18
years): 0.5–1.0 mg/dL or 44–88 µmol/L Young children (0–3 years): 0.3–0.7 mg/dL or 27–62 µmol/L BUN/creatinine ratio:
10:1 to 20:1
Procedure
1. Obtain a 5-mL venous blood sample. Serum is preferred, but heparinized blood can be used. Place specimen in a
biohazard bag.
2. Observe standard precautions.
Clinical Implications
1. Increased blood creatinine levels occur in the following conditions:
a. Impaired renal function
b. Chronic nephritis
c. Obstruction of urinary tract
d. Muscle disease
1. Gigantism
2. Acromegaly
3. Myasthenia gravis
4. Muscular dystrophy
5. Poliomyelitis
e. Congestive heart failure
f. Shock
g. Dehydration
h. Rhabdomyolysis
i. Hyperthyroidism
2. Decreased creatinine levels occur in the following conditions:
a. Small stature
b. Decreased muscle mass
c. Advanced and severe liver disease
d. Inadequate dietary protein
e. Pregnancy (0.4–0.6 mg/dL or 36–53 µmol/L is normal; >0.8 mg/dL or >71 µmol/L is abnormal and should be
noted)
3. Increased ratio (>20:1) with normal creatinine occurs in the following conditions:
a. Increased BUN (prerenal azotemia), heart failure, salt depletion, dehydration
b. Catabolic states with tissue breakdown
c. GI hemorrhage
d. Impaired renal function plus excess protein intake, production, or tissue breakdown
4. Increased ratio (>20:1) with elevated creatinine occurs in the following conditions:
a. Obstruction of urinary tract
b. Prerenal azotemia with renal disease
5. Decreased ratio (<10:1) with decreased BUN occurs in the following conditions:
a. Acute tubular necrosis
b. Decreased urea synthesis as in severe liver disease or starvation
c. Repeated dialysis

d. SIADH
e. Pregnancy
6. Decreased ratio (<10:1) with increased creatinine occurs in the following conditions:
a. Phenacemide therapy (accelerates conversion of creatine to creatinine)
b. Rhabdomyolysis (releases muscle creatinine)
c. Muscular patients who develop renal failure
Interfering Factors
1. High levels of ascorbic acid and cephalosporin antibiotics can cause a falsely increased creatinine level; these
agents also interfere with BUN/creatinine ratio.
2. Drugs that influence kidney function plus other medications can cause a change in the blood creatinine level (see
Appendix J).
3. A diet high in meat can cause increased creatinine levels.
4. Creatinine is falsely decreased by bilirubin, glucose, histidine, and quinidine compounds.
5. Ketoacidosis may increase serum creatinine substantially.

Clinical Alert
1. Panic value is 10 mg/dL or 890 µmol/L in nondialysis patients.
2. Creatinine level should always be checked before administering nephrotoxic chemotherapeutics such as
methotrexate, cisplatin, cyclophosphamide, mithramycin, and semustine.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Assess diet for meat and protein intake.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test results and monitor as appropriate for impaired renal function.
2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Cystatin C
Cystatin C is a low-molecular-weight protein inhibitor found in blood serum and is an indicator of glomerular filtration in
kidney function.
This test is done to assess glomerular filtration rate (GFR) in the elderly. Cystatin C may be a more reliable indicator of
renal function in the elderly than is the creatinine level. GFR and kidney size decline with age and thus creatinine levels
may be unreliable as an indicator of GFR.
Reference Values
Normal Young adults: <0.70 mg/mL (<2.9 µmol/mL) Elderly adults: <0.85 mg/mL (<3.5 µmol/mL)
Procedure
1. No fasting is required.
2. Obtain a venous blood sample.
Clinical Implications Cystatin C levels abnormally increase in association with impaired renal function and loss of
kidney homeostasis, as in acute renal failure, chronic renal failure, diabetic nephropathy, and infections.
Interventions
Pretest Patient Care
1. Explain purpose and sampling procedure for cystatin C.
2. Assess for signs of abnormal kidney function (hypertension, pain, edema, uremia, disorders of urination, and urine
composition). Some conditions have no symptoms of nephrotic syndrome.
3. Follow Chapter 1 guidelines for safe, effective, informed pretest care.
Posttest Patient Care
1. Interpret outcomes and provide the patient with support and counseling.
2. Explain follow-up testing and possible treatment for kidney disease.
3. See Chapter 1 guidelines for safe, effective, informed posttest care .
Uric Acid
Uric acid is formed from the breakdown of nucleonic acids and is an end product of purine metabolism. Uric acid is
transported by the plasma from the liver to the kidney, where it is filtered and where about 70% is excreted. The
remainder of uric acid is excreted into the GI tract and degraded. A lack of the enzyme uricase allows this poorly soluble
substance to accumulate in body fluids.

The basis for this test is that an overproduction of uric acids occurs when there is excessive cell breakdown and
catabolism of nucleonic acids (as in gout), excessive production and destruction of cells (as in leukemia), or an inability
to excrete the substance produced (as in renal failure). Measurement of uric acid is used most commonly in the
evaluation of renal failure, gout, and leukemia. In hospitalized patients, renal failure is the most common cause of
elevated uric acid levels, and gout is the least common cause.
Reference Values
Normal Men: 3.4–7.0 mg/dL or 202–416 µmol/L Women: 2.4–6.0 mg/dL or 143–357 µmol/L Children: 2.0–5.5 mg/dL or
119–327 µmol/L
Procedure
1. Obtain a 5-mL venous blood sample. Serum is preferred; heparinized blood is acceptable. Place specimen in a
biohazard bag.
2. Observe standard precautions.
Clinical Implications
1. Elevated uric acid levels (hyperuricemia) occur in the following conditions:
a. Gout (the amount of increase is not directly related to the severity of the disease)
b. Renal diseases and renal failure, prerenal azotemia
c. Alcoholism (ethanol consumption)
d. Down syndrome
e. Lead poisoning
f. Leukemia, multiple myeloma, lymphoma
g. Lesch-Nyhan syndrome (hereditary gout)
h. Starvation, weight-loss diets
i. Metabolic acidosis, diabetic ketoacidosis
j. Toxemia of pregnancy (serial determination to follow therapy)
k. Liver disease
l. Hyperlipidemia, obesity
m. Hypoparathyroidism, hypothyroidism
n. Hemolytic anemia, sickle cell anemia
o. Following excessive cell destruction, as in chemotherapy and radiation treatment (acute elevation sometimes
follows treatment)
p. Psoriasis
q. Glycogen storage disease (G6PD deficiency)
2. Decreased levels of uric acid occur in the following conditions:
a. Fanconi's syndrome
b. Wilson's disease
c. SIADH
d. Some malignancies (eg, Hodgkin's disease, multiple myeloma)
e. Xanthinuria (deficiency of xanthine oxidase)
Interfering Factors
1.
2.
3.
4.
5.

Stress and strenuous exercise will falsely elevate uric acid.
Many drugs cause increase or decrease of uric acid (see Appendix J).
Purine-rich diet (eg, liver, kidney, sweetbreads) increases uric acid levels.
High levels of aspirin decrease uric acid levels.
Low purine intake, coffee, and tea decrease uric acid levels.

Interventions
Pretest Patient Care
1. Advise patient of test purpose and blood-drawing procedure; fasting is preferred.
2. Promote relaxation; avoid strenuous exercise.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results and monitor appropriately for renal failure, gout, or leukemia. Uric acid level should fall in
patients who are treated with uricosuric drugs such as allopurinol, probenecid, and sulfinpyrazone.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Clinical Alert
1. Monitor uric acid levels during treatment of leukemia.
2. Acute, dangerous levels may occur following administration of cytotoxic drugs.
Lead (Pb)
Lead is absorbed into the body through both the respiratory and GI tracts. It also moves transplacentally to the fetus.

Absorption through these different routes varies and is affected by age, nutritional status, particle size, and chemical form
of the lead. Absorption is inversely proportional to particle size; this factor makes lead-bearing dust important. Adults
absorb 6% to 10% of dietary lead and retain very little of it; however, children from birth to 2 years of age have been
shown to absorb 40% to 50% and to retain 20% to 25% of dietary lead. Spontaneous excretion of lead in urine by infants
and young toddlers is normally about 1 µg/kg/24 hours, which may increase somewhat in cases of acute poisoning.
Dietary intake of lead is <1 µg/kg of lead, which provides a margin of safety in the sense that a child goes into positive
lead balance when intake exceeds 5 µg/kg of body weight. Early symptoms of lead poisoning include anorexia, apathy or
irritability, fatigue, and anemia. Toxic effects include GI distress, joint pain, colic, headache, stupor, convulsions, and
coma. Another test that may be used to evaluate lead intoxication is free erythrocyte protoporphyrin. However, a blood
lead assay is the definitive test.
The blood lead assay is used to screen adults and children for lead poisoning (plumbism). In adults, high levels are
caused mainly by industrial exposure from lead-based paints, gasoline, and ceramics. High-risk children usually are aged
3 to 12 years and live in or visit old or dilapidated housing with lead-based paint. A single paint chip can contain as much
as 10,000 µg of lead.
Reference Values
Normal 0–10 µg/dL or 0–0.48 µmol/L
Procedure
1. Obtain a sample by finger stick using lead-free heparinized capillary tubes or venous blood drawn in a 3-mL trace
element–free tube. Place specimen in a lead-free biohazard bag or container.
2. Do not separate plasma from cells. Refrigerate the sample.
3. Observe standard precautions.
Clinical Implications Blood lead levels in adults:
1.
2.
3.
4.

<10 µg/dL or <0.48 µmol/L: normal without occupational exposure
<20 µg/dL or <0.97 µmol/L: acceptable with occupational exposure
>40 µg/dL or >1.9 µmol/L: report to state occupational agency
>60 µg/dL or >2.9 µmol/L: remove from occupational exposure and begin chelation therapy

Table 6.6 lists the U.S. Centers for Disease Control and Prevention (CDC) classifications for levels of blood lead. See
Table 6.7 for the effects of blood lead in children.
Table 6.6 U.S Centers for Disease Control and Prevention Classifications of Blood Lead Levels
Class Blood Lead *

Action

I
<10 µg/dL or 0.48 µmol/L
Not lead poisoned
IIA
10–14 µg/dL or 0.48–0.68 µmol/L
Rescreen frequently and consider prevention activities
IIB
15–19 µg/dL or 0.72–0.92 µmol/L
Institute nutritional and educational interventions
III
20–44 µg/dL or 0.97–2.1 µmol/L
Evaluate environment and consider chelation therapy
IV
45–69 µg/dL or 2.17–3.33 µmol/L
Institute environmental intervention and chelation therapy
V
>69 µg/dL or 3.33 µmol/L
Medical emergency
*Owing to possible contamination during collection, elevated levels should be confirmed with a second specimen before
therapy is instituted.

Table 6.7 Effects of Increased Blood Lead Levels on Children
Blood Lead Level

Effects in Children

>10 µg/dL or >0.48 µmol/L
Reduced IQ, hearing, and growth
>20 µg/dL or >0.97 µmol/L
Impaired nerve function
>30 µg/dL or >1.45 µmol/L
Reduced vitamin D metabolism
>40 µg/dL or >1.93 µmol/L
Damage to blood-forming system
>50 µg/dL or >2.41 µmol/L
Severe stomach cramps
>60 µg/dL or >2.90 µmol/L
Severe anemia
>80 µg/dL or >3.86 µmol/L
Severe brain damage
>125 µg/dL or >6.04 µmol/L
Death
Source: President's Task Force on Environmental Health Risks and Safety Risks to Children: Federal strategy to
eliminate childhood lead poisoning, March 2002 (Online) Accessible at www.hud.gov/lea

Interfering Factors
1. Failing to use lead-free Vacutainer tubes invalidates results.
2. An elevated level should be confirmed with a new second specimen to ensure that the specimen was not
contaminated.

Clinical Alert
1. Critical values:
a. <15 years of age, >20 µg/dL or >0.97 µmol/L; =15 years of age, >30 µg/dL or >1.45 µmol/L
b. Patients with blood lead concentrations >80 µg/dL or >3.86 µmol/L (panic value) should be hospitalized
immediately and treated as medical emergencies.
c. A single lead determination cannot distinguish between chronic and acute exposure.
2. Following chelation therapy, lead levels are assessed at varying intervals, and it is not unusual to see a slight
increase due to lead leeching from bones.
3. Pregnant women with blood lead levels (BLL) > 10 µg/dL or >0.48 µmol/L are at risk for delivering a child with a
BLL also > 10 µg/dL or >0.48 µmol/L.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Explain the importance of follow-up if lead levels are elevated.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results, counsel, and monitor appropriately for elevated lead levels. Explain chelation therapy and
possible need for further testing, eg, iron deficiency and blood protoporphyrins.
a. Parental compliance is necessary. Parent education about lead poisoning can be given face-to-face, by
pamphlet distribution, or in both ways.
b. The most important component of medical management is to facilitate reduction in the child's exposure to the
environmental lead. In providing intervention for the child with an elevated blood lead level, the initial step is to
obtain a detailed environmental history. The causes of childhood lead poisoning are multiple and must take into
account potential environmental hazards as well as characteristics of the individual child. Once a child is found
to have lead intoxication, all potential sources must be identified and removed from the child's environment.
c. The recommended diet for a child with lead toxicity is simply a good diet with adequate protein and mineral
intake and limitation of excess fat. It is no longer necessary to exclude canned foods and beverages when the
cans are manufactured in the United States because the manufacture of cans with lead-soldered seams ended
in the United States in 1991.
d. Iron deficiency can enhance absorption and toxicity of lead and often coexists with overexposure to lead. All
children with a blood lead concentration >20 µg/dL or >0.97 µmol/L whole blood should have appropriate testing
for iron deficiency.
e. In class IV lead intoxication, chelation is necessary. Chelation therapy must be done in conjunction with
eliminating the source of the lead poisoning. Chelation therapy, when promptly administered, can be life-saving
and can reduce the period of morbidity associated with lead toxicity.
f. Additional follow-up tests may be ordered, including free erythrocyte protoporphyrin or erythrocyte HNC
protoporphyrin.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Osteocalcin (Bone G1a Protein)
Osteocalcin, also referred to as bone G1a protein, is a protein produced by the osteoblasts and dentin and has a function
in bone mineralization and calcium ion homeostasis. A small amount of osteocalcin, an integral part in bone formation, is
released into the blood and therefore can serve as a marker for recent bone formation. Osteocalcin levels are influenced
by age (rapid growth), gender (males somewhat higher), and are increased during menopause. This test is used to
screen for osteoporosis in postmenopausal women, assess risk for fractures, and determine eligibility for treatment for
osteoporosis. Osteocalcin is a specific marker for bone formation and is regulated by 1, 25-dehydroxy vitamin D.
Reference Values
Normal Osteocalcin: 8.1 ± 4.6 µg/L or 1.4 ± 0.8 nmol/L Carboxylated osteocalcin: 9.9 ± 0.5 µg/L or 1.7 ± 0.1 nmol/L
Undercarboxylated osteocalcin: 3.7 ± 1.0 µg/L or 0.6 ± 0.2 nmol/L
Normal Using RIA Adult male: 3.0–13.0 ng/mL or 3.0–13.0 µg/L Premenopausal female: 0.4–8.2 ng/mL or 0.4–8.2 µg/L
Postmenopausal female: 1.5–11.0 ng/mL or 1.5–11.0 µg/L There is a diurnal variation, a peak during the night and a
decrease in the morning.
Procedure Collect a venous blood sample of serum on ice, separate within 1 hour, and immediately freeze. Avoid a
freeze–thaw cycle.
Interfering Factors
1. Increased during bed rest and no increase in bone formation.
2. Increased with impaired renal function and no increase in bone formation.
Clinical Implications
1. Abnormally increased levels indicate increased bone formation in persons with hyperparathyroidism, fractures, and
acromegaly.
2. Decreased levels are associated with hypoparathyroidism, a deficiency of growth hormone, and medications such
as glucocorticoids, bisphosphonates, and calcitonin.
Interventions

Pretest Patient Care
1. Explain purpose and procedure of test. Record age and menopausal state. Tell patient that the risk for osteoporosis
steadily increases with age. Also obtain pertinent personal and family history of osteoporetic fractures, history of
falls, etc.
2. Follow Chapter 1 guideline for safe, effective, informed pretest care.
Posttest Patient Care
1. Interpret test outcomes and counsel regarding further tests (eg, dual-energy x-ray absorptiome [DXA] [bone density
of the femoral neck] or quantitative ultrasound) and possible treatment (eg, medical: alendronate, raloxifene).
Sixteen percent of postmenopausal women will be found to have lumbar spine osteoporosis. Other blood test
markers of bone resorption include pyridinolines, telopeptides, acid phosphatase, and urine tests of hydroxyproline
and galactosyl hydroxlysine. These markers are known as collagen cross-links.
2. See Chapter 1 for safe, effective, informed posttest care .

HORMONE TESTS
Androstenedione
Androstenedione is one of the major androgens produced by the ovaries in females, and to a lesser extent in the adrenal
in both genders. This hormone is converted to estrogens by hepatic enzymes. Levels rise sharply after puberty and peak
at age 20 years.
This hormone measurement is helpful in the evaluation of conditions characterized by hirsutism and virilization. In
females, there is poor correlation of plasma levels with clinical severity.
Reference Values
Normal Newborns: 20–290 ng/dL or 0.7–10.1 mmol/L Prepuberty: 8–50 ng/dL or 0.3–1.7 mmol/L Women: 75–205 ng/dL
or 2.6–7.2 mmol/L Men: 85–275 ng/dL or 3.0–9.6 mmol/L Postmenopausal women: <10 ng/dL or 0.35 mmol/L (abrupt
decline at menopause) Different laboratories may have variation in reference values.
Procedure
1. Obtain a 5-mL venous blood sample in the morning and place on ice. Serum or EDTA can be used. Observe
standard precautions. Place specimen in a biohazard bag.
2. In women, collect this specimen 1 week before or after the menstrual period. Record date of last menstrual period
on the laboratory form.
Clinical Implications
1. Increased androstenedione values are associated with the following conditions:
a. Stein-Leventhal syndrome
b. Cushing's syndrome
c. Certain ovarian tumors (polycystic ovarian syndrome)
d. Ectopic ACTH-producing tumor
e. Late-onset congenital adrenal hyperplasia
f. Ovarian stromal hyperplasia
g. Osteoporosis in females
2. Decreased androstenedione values are found in the following conditions:
a. Sickle cell anemia
b. Adrenal and ovarian failure

Clinical Alert
>1000 mg/dL or >34.9 mmol/L (suggests virilizing tumor)
Interventions
Pretest Patient Care
1. Explain purpose of test and blood-drawing procedure. Obtain pertinent history of signs and symptoms (eg,
excessive hair growth and infertility).
2. Ensure that patient is fasting and that blood is drawn at peak production (7:00 a.m.). Lowest levels are at 4:00 p.m.
3. Collect specimen 1 week before menstrual period in women.
4. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results and counsel appropriately for ovarian and adrenal dysfunction.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Aldosterone
Aldosterone is a mineralocorticoid hormone produced in the adrenal zona glomerulosa under complex control by the

renin-angiotensin system. Its action is on the renal distal tubule, where it increases resorption of sodium and water at the
expense of increased potassium excretion.
This test is useful in detecting primary or secondary aldosteronism. Patients with primary aldosteronism characteristically
have hypertension, muscular pains and cramps, weakness, tetany, paralysis, and polyuria. It is also used to evaluate
causes of hypertension (found in 1% of hypertension cases).

NOTE
A random aldosterone test is of no diagnostic value unless a plasma renin activity is done at the same time.
Reference Values Normal (In upright position) Adults: 7–30 ng/dL or 0.19–0.83 nmol/L Adolescents: 4–48 ng/dL or
0.11–1.33 nmol/L Children: 5–80 mg/dL or 0.14–2.22 nmol/L Low-sodium diet: values 3–5 times higher
Procedure
1. Take plasma with the patient in an upright position for 2 hours and with unrestricted salt intake.
2. Obtain a 5-mL venous blood specimen in a heparinized or EDTA Vacutainer tube. Serum, EDTA, or heparinized
blood may be used. The cells must be separated from plasma immediately. Blood should be drawn with patient
sitting. Observe standard precautions.
3. Specify and record the time of the venipuncture. Circadian rhythm exists in normal subjects, with levels of
aldosterone peaking in the morning. Specify if the blood has been drawn from the adrenal vein (values are much
higher: 200–800 ng/dL or 5.5–22.6 mmol/L).
4. Be aware that a 24-hour urine specimen with boric acid preservative may also be ordered. Refrigerate immediately
following collection.
5. Have patient follow a normal sodium diet 2–4 weeks before test.
6. Ensure that low potassium is treated before test.
Clinical Implications
1. Elevated levels of aldosterone (primary aldosteronism) occur in the following conditions:
a. Aldosterone-producing adenoma (Conn's disease)
b. Adrenocortical hyperplasia (pseudoprimary aldosteronism)
c. Indeterminate hyperaldosteronism
d. Glucocorticoid remediable hyperaldosteronism
2. Secondary aldosteronism, in which aldosterone output is elevated because of external stimuli or greater activity in
the renin-angiotensin system, occurs in the following conditions:
a. Salt depletion
b. Potassium loading
c. Laxative abuse
d. Cardiac failure
e. Cirrhosis of liver with ascites
f. Nephrotic syndrome
g. Bartter's syndrome
h. Diuretic abuse
i. Hypovolemia and hemorrhage
j. After 10 days of starvation
k. Toxemia of pregnancy
3. Decreased aldosterone levels are found in the following conditions:
a. Aldosterone deficiency
b. Addison's disease
c. Syndrome of renin deficiency (very rare)
d. Low aldosterone levels associated with hypertension are found in Turner's syndrome, diabetes mellitus, and
alcohol intoxication
Interfering Factors
1.
2.
3.
4.
5.
6.

Values are increased by upright posture.
Recently administered radioactive medications affect test outcomes.
Heparin therapy causes levels to fall. See Appendix J for drugs that increase and decrease levels.
Thermal stress, late pregnancy, and starvation cause levels to rise.
Aldosterone levels decrease with age.
Many drugs—diuretics, antihypertensives, progestogens, estrogens, and licorice—should be terminated 2–4 weeks
before test.

Clinical Alert
1. The simultaneous measurement of aldosterone and renin is helpful in differentiating primary from secondary
hyperaldosteronism. Renin levels are high in secondary aldosteronism and low in primary aldosteronism.
2. Potassium deficiencies should be corrected before testing for aldosterone.
Interventions
Pretest Patient Care
1. Explain test purpose and procedures. Assess for history of diuretic or laxative abuse. If 24-hour urine specimen is
required, follow protocols in Chapter 3.

2. Discontinue diuretic agents, progestational agents, estrogens, and black licorice for 2 weeks before the test.
3. Ensure that the patient's diet for 2 weeks before the test is normal (other than the previously listed restrictions) and
should include 3 g/day (135 mEq/L/day) of sodium. Check with your laboratory for special protocols.
4. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities and diet.
2. Interpret test results and monitor appropriately for aldosteronism and aldosterone deficiency.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Antidiuretic Hormone (ADH); Arginine Vasopressin Hormone
ADH is excreted by the posterior pituitary gland. When ADH activity is present, small volumes of concentrated urine are
excreted. When ADH is absent, large amounts of diluted urine are produced. Higher secretion occurs at night, with erect
posture, and with pain, stress, or exercise. Measurement of the level of ADH is useful in the differential diagnosis of
polyuric and hyponatremic states. ADH testing aids in diagnosis of urine concentration disorders, especially diabetes
insipidus, SIADH, psychogenic water intoxication, and syndromes of ectopic ADH production.
Reference Values
Normal <2.5 pg/mL or <2.3 pmol/L
Procedure
1. Draw venous blood samples, 5 mL, into prechilled tubes and put on ice. Plasma with EDTA anticoagulant is
needed. Observe standard precautions. Place specimen in a biohazard bag.
2. Ensure that patient is in a sitting position and calm during blood collection.
Clinical Implications
1. Increased secretion of ADH is associated with the following conditions:
a. SIADH (with respect to plasma osmolality)
b. Ectopic ADH production (systemic neoplasm)
c. Nephrogenic diabetes insipidus
d. Acute intermittent porphyria
e. Guillain-Barré syndrome
f. Brain tumor, diseases, injury, neurosurgery
g. Pulmonary diseases (tuberculosis)
2. Decreased secretion of ADH occurs in the following conditions:
a. Central diabetes insipidus (hypothalamic or neurogenic)
b. Psychogenic polydipsia (water intoxication)
c. Nephrotic syndrome
Interfering Factors
1. Recently administered radioisotopes cause spurious results.
2. Many drugs affect results (eg, thiazide diuretics, oral hypoglycemics, and narcotics); see Appendix J.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Encourage relaxation before and during blood-drawing procedure.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Resume normal activities.
2. Interpret test results and counsel appropriately for urine concentration disorders and polyuria.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Clinical Alert
To distinguish SIADH from other conditions that cause dilutional hyponatremia, other tests must be done, such as
plasma osmolality, plasma sodium, and water-loading test.
Atrial Natriuretic Factor (ANF), ANP and BNP
Atrial natriuretic factor (ANF) is a hormone secreted by the cardiac atria during acute and chronic cardiac volume and
pressure overload. The discovery of ANF indicates that the heart is an endocrine gland and confirms speculation that
there is a mechanism in or near the heart that regulates body fluid hemostasis. This hormone enhances salt and water
excretion, blocks aldosterone and renal secretion, and inhibits the action of angiotensin II and vasopressin.
Recently, a hormone produced by the ventricles of the heart, brain natriuretic peptide or B-type natriuretic peptide (BNP),

has been shown to increase in response to ventricular volume expansion and pressure overload. BNP is a marker of
ventricular systolic and diastolic dysfunction. This test is useful in diagnosing congestive heart failure. It is not useful for
diagnosing other heart conditions. Chart 6.1 describes types of heart failures; Chart 6.2 offers a scale for grading them.
Figure 6.3 illustrates the relationship of BNP to heart disease.

Chart 6.1 Heart Failure

Type of Heart Failure
Left heart failure ( congestive heart failure)
Systolic heart failure (systolic ventricular dysfunction);
inability of the heart to generate an adequate cardiac
utput to perfuse vital tissues
Diastolic heart failure (diastolic ventricular failure);
pulmonary congestion despite a normal stroke volume

Signs and Symptoms
Shortness of breath
at rest and exercise
Persistent cough
Weakness or fatigue
Edema in feet,
ankles, legs
Weight gain

Tests to Diagnose
History/physical exam
Electrocardiogram
Echocardiography
Chest x-ray
Blood tests: brain natriuretic
peptide, atrial natriuretic factor
Pulmonary function tests
Cardiac ultrasound
Treadmill stress test
Thallium stress test

Right heart failure
An increase in left ventricular filling pressure that is reflected
back in the pulmonary circulation
High-output failure
Inability of the heart to supply the body with blood-borne
nutrients despite adequate blood volume and normal
myocardial contractility

Chart 6.2 Grading Heart Diseases
Class I—no limitation of physical activity; no fatigue, shortness of breath, or heart palpitations with ordinary activities
Class II—slight limitation in physical activity; with fatigue, shortness of breath, or heart palpitations during ordinary
activities
Class III—marked limitation of physical activity; with fatigue, shortness of breath, or heart palpitations with
less-than-ordinary physical activity
Class IV—severe to complete limitation of physical activity with fatigue, shortness of breath, or heart palpitations with
any exertion; symptoms occur even at rest
Footnote
Source: The New York Heart Association, 2001

FIGURE 6.3 Relationship of BNP to heart disease (classification of the New York Heart Association) (Source: Biosite
Diagnostics, San Diego, CA, USA)
Reference Values
Normal Atrial natriuretic factor (ANF): 20–77 pg/mL or 20–77 ng/L B-type natriuretic peptide (BNP): <100 pg/mL or <100
ng/L
Procedure
1. Obtain a plasma sample by venipuncture from a fasting patient. Use a lavender-topped KEDTA tube. If a nonfasting
sample is obtained, notify laboratory.
2. Prechill the tube at 4°C before drawing sample. After drawing sample, chill tube in wet ice for 10 minutes. Place

specimen in a biohazard bag.
Clinical Implications Increased ANF levels occur in:
1.
2.
3.
4.

Congestive heart failure
Cardiovascular disease with elevated filling pressure
A symptomatic cardiac volume overload
Paroxysmal atrial tachycardia

Interfering Factors See Appendix J for drugs that affect test outcomes.
Interventions
Pretest Patient Care
1. Explain test purpose and need to fast. Assess for signs and symptoms indicating need for testing (eg, chronic
fatigue, cough, heart palpitations, high blood pressure).
2. Withhold cardiovascular medications per physician's order (eg, ß and calcium antagonists, cardiac glycosides,
diuretics, vasodilators) before drawing specimen.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1.
2.
3.
4.

Medications and usual diet may be restarted per physician's order.
Evaluate patient outcomes and monitor appropriately for congestive heart failure.
In collaboration with physician, explain need for possible follow-up tests and medication therapy.
Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Cortisol (Hydrocortisone)
Cortisol (hydrocortisone/compound F) is a glucocorticosteroid of the adrenal cortex and affects metabolism of proteins,
carbohydrates, and lipids. Cortisol stimulates glucogenesis by the liver, inhibits the effect of insulin, and decreases the
rate of glucose use by the cells. In health, the secretion rate of cortisol is higher in the early morning (6:00–8:00 a.m.)
and lower in the evening (4:00–6:00 p.m.). This variation is lost in patients with Cushing's syndrome and in persons
under stress.
The cortisol test evaluates adrenal hormone function. Cortisol is elevated in adrenal hyperfunction and decreased in
adrenal hypofunction. Suppression and stimulation tests may also be done. Cortisol (dexamethasone) suppression test
screens for Cushing's syndrome and identifies depressed persons who are likely to respond to antidepressants or
electroshock therapy. It is based on the fact that ACTH production is suppressed in healthy persons after a low dose of
dexamethasone but not in persons with Cushing's syndrome or in some depressed persons.
Reference Values
Normal Cortisol 8:00 a.m.: 5–23 µg/dL or 138–635 nmol/L 4:00 p.m.: 3–16 µg/dL or 83–441 nmol/L Midnight: <50% of
8:00 a.m. level Newborns: 2–11 µg/dL or 55–304 nmol/L Maternal (at birth): 51.2–57.4 µg/dL or 1413–1584 nmol/L After
first week of life, cortisol levels attain adult values. Suppression 8:00 a.m. following administration of dexamethasone: <5
µg/dL (a.m. value) or <138 nmol/L Stimulation Baseline: at least 5 µg/dL or 138 nmol/L After Cortrosyn administration:
rise of at least 10 µg/dL or 276 nmol/L
Procedure
1. Obtain 5-mL venous blood samples at 8:00 a.m. and at 4:00 p.m. Serum is preferred. Heparin anticoagulant may be
used. Place specimen in a biohazard bag.
2. Observe standard precautions.
Clinical Implications
1. Decreased cortisol levels are found in the following conditions:
a. Adrenal hyperplasia
b. Addison's disease
c. Anterior pituitary hyposecretion (pituitary destruction)
d. Hypothyroidism (hypopituitarism)
2. Increased cortisol levels are found in the following conditions:
a. Hyperthyroidism
b. Stress (trauma, surgery)
c. Carcinoma (extreme elevation in the morning and no variation later in the day)
d. Cushing's syndrome (high on rising but no variation later in the day)
e. Overproduction of ACTH due to tumors (oat cell cancers)
f. Adrenal adenoma
g. Obesity
Interfering Factors
1.
2.
3.
4.

Pregnancy will cause an increased value.
There is no normal diurnal variation in patients under stress.
Drugs such as spironolactone and oral contraceptives will give falsely elevated values (see Appendix J).
Decreased levels occur in persons taking dexamethasone, prednisone, or prednisolone (steroids) (see Appendix J).

5. Random cortisol tests are useless and provide no pertinent information.
Interventions
Pretest Patient Care
1.
2.
3.
4.

Explain test purpose and blood-drawing procedure. Blood must be drawn at 8:00 a.m. and 4:00 p.m.
Encourage relaxation.
Ensure that no radioisotopes are administered within 1 day before the test.
Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results and counsel appropriately for adrenal dysfunction.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Cortisol Suppression (Dexamethasone Suppression; DST)
See foregoing cortisol test for purpose and indications. The DST test helps to differentiate causes of elevated cortisol.
Cortisol <15 µg/dL (<41.4 nmol/L) is indication of adrenal cortisol insufficiency.
Reference Values
Normal <5 µg/dL (<138 nmol/L) or <50% of baseline (8:00 a.m. specimen)
Procedure
1. Obtain a 5-mL venous blood the day following administration of dexamethasone. Serum or heparinized plasma is
acceptable. Observe standard precautions. Place specimen in a biohazard bag.
2. Administer late evening or bedtime; dexamethasone tablets by mouth. There is a low-dose and high-dose
suppression test in which either 1.0 mg or 8.0 mg of dexamethasone is given, respectively, at 11:00 p.m. The
following morning at 8:00 a.m., a blood sample is drawn to measure cortisol. (Some Cushing's disease patients
have false-positive results with this low dose.)
Clinical Implications
1. Suppression occurs in persons with:
a. Cushing's syndrome (>10 µg/dL or >276 nmol/L)
b. Endogenous depression (50% of cases)
2. No suppression occurs in:
a. Adrenal adenoma, carcinoma
b. Ectopic ACTH-producing tumors
Interfering Factors False suppression can occur in the following conditions:
1.
2.
3.
4.
5.
6.

Pregnancy
High doses of estrogens
Alcoholism
Uncontrolled diabetes
Trauma, high stress, fever, dehydration
Phenytoin (Dilantin) (see Appendix J for other drugs)

Interventions
Pretest Patient Care
1. Explain test purpose and procedure. Fasting is required for the 8:00 a.m. test.
2. Discontinue all medications for 24 to 48 hours before the study. Especially important are spironolactone, estrogens,
birth control pills, cortisol, tetracycline, stilbestrol, and phenytoin. Check with the physician.
3. Weigh the patient and record weight.
4. Have baseline blood cortisol drawn at 8:00 a.m. and 4:00 p.m. Give 1 mg dexamethasone at 11:00 p.m. the same
day. Draw blood at 8:00 a.m. the next morning.
5. Ensure that no radioisotopes are administered within 1 week before test.
6. Follow guidelines in Chapter 1 regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results and counsel appropriately for Cushing's syndrome or depression.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Cortisone Stimulation (Cosyntropin, Cortrosyn Stimulation); Adrenocorticotropin Hormone (ACTH) Stimulation
This detects adrenal insufficiency after Cortrosyn administration. Cortrosyn is a synthetic subunit of ACTH that exhibits
the full corticosteroid-stimulating effect of ACTH in healthy persons. Failure to respond is an indication of adrenal
insufficiency. See foregoing cortisol tests for values. This screening test is less time consuming and can be done on an

outpatient basis.
Reference Values
Normal Cortisol: >20 µg/dL (>552 nmol/L) rise after Cortrosyn administration
Procedure
1. Obtain a 4-mL fasting venous blood sample at 8:00 a.m. Observe standard precautions.
2. Administer Cortrosyn intramuscularly or intravenously as prescribed.
3. Obtain additional 4-mL blood specimens 30 and 60 minutes after administration of Cortrosyn. Serum or heparinized
blood is acceptable.
Clinical Implications
1. Absent or blunted response to cortisol stimulation occurs in the following conditions:
a. Addison's disease (adrenal insufficiency)
b. Hypopituitarism (secondary adrenal insufficiency)
c. Adrenal carcinoma, adenoma
2. Response to cortisol stimulation: adrenal hyperplasma
Interfering Factors
1. Prolonged steroid administration
2. Estrogens (see Appendix J)
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. Fasting during test is required. Blood specimens are obtained before and after
IM injection of Cortrosyn.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results and monitor appropriately for adrenal insufficiency.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Clinical Alert
In adrenal hyperplasia, there is an increase of cortisol levels of 3 to 5 times the normal; in adrenal carcinoma, there is
no increase.
Gastrin
Gastrin, a hormone secreted by the antral G cells in stomach mucosa, stimulates gastric acid production and affects
antral motility and secretion of pepsin and intrinsic factor. Gastrin values follow a circadian rhythm and fluctuate
physiologically in relation to meals. The lowest values are between 3:00 a.m. and 7:00 a.m.
Measurement of serum gastrin is generally used to diagnose stomach disorders such as gastrinoma and Zollinger-Ellison
syndrome in the presence of hyperacidity. (Gastric hyperacidity must be documented.)
Reference Values
Normal Adults: <25–100 pg/mL or <12–48 pmol/L Children: 10–125 pg/mL or 5–60 pmol/L Postprandial: 95–140 pg/mL
or 46–67 pmol/L
Procedure
1. Obtain a 5-mL venous blood sample from a fasting patient. Serum is required.
2. Freeze if not tested immediately. If not fasting, this must be noted because values are different. Place specimen in
a biohazard bag.
3. Observe standard precautions.
Clinical Implications
1. Increased gastrin levels are found in the following conditions:
a. Stomach carcinoma (reduction of gastric acid secretion)
b. Gastric and duodenal ulcers
c. Zollinger-Ellison syndrome (>500 pg/mL or >240 pmol/L)
d. Pernicious anemia
e. Gastric carcinoma
f. End-stage renal disease (gastrin metabolized by the kidneys)
g. Antral G-cell hyperplasia
h. Vagotomy without gastric resection
i. Hyperparathyroidism

j. Pyloric obstruction
2. Decreased gastrin levels occur in the following conditions:
a. Antrectomy with vagotomy
b. Hypothyroidism
Interfering Factors Values will be falsely increased in nonfasting patients, elderly patients, and diabetic patients taking
insulin, as well as in postgastroscopy patients and those taking H 2 secretion blockers (cimetidine), steroids, and
calcium. A protein meal can elevate gastrin markedly.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Remind patient that fasting is required for 12 hours preceding the test. Water is permitted; no coffee. No
radioisotopes for 1 week.
3. Note if specimen is drawn postprandial. (If after eating, note what was eaten.)
4. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results and monitor appropriately. Follow-up testing using gastric stimulation or gastrin suppression
may be indicated.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Growth Hormone (hGH); Somatotropin
Human growth hormone (somatotropin, hGH) is essential to the growth process and has an important role in the
metabolism of adults. It is secreted by the pituitary gland in response to exercise, deep sleep, hypoglycemia, glucagon,
insulin, and vasopressin. It also stimulates the production of RNA, mobilizes fatty acids from fat deposits, and is
intimately connected with insulinism. If the pituitary gland secretes too little or too much hGH in the growth phase of life,
dwarfism or gigantism will result, respectively. An excess of growth hormone during adulthood leads to acromegaly.
This test confirms hypopituitarism or hyperpituitarism so that therapy can be initiated as soon as possible. Challenge or
stimulation tests are generally used to detect hGH deficiency and are more informative. Much controversy surrounds the
use of growth hormone stimulation tests, and the diagnosis should be considered in the context of the clinical picture.
Reference Values
Normal Men: <5 ng/mL or <226 pmol/L Women: <10 ng/mL or <452 pmol/L Children: 0–20 ng/mL or 0–904 pmol/L
Newborns: 5–40 ng/mL or 226–1808 pmol/L Stimulation test (using arginine, glucagon or insulin): >5 ng/mL or >226
pmol/L (rise from baseline) >10 ng/mL or >452 pmol/L peak response from baseline Suppression test (using 100 g
glucose): 0–2 ng/mL or 0–90 pmol/L or undetectable

NOTE
Because of marked fluctuations in hGH, a random specimen has limited value. Stimulation or inhibitor tests provide
more information.
Procedure
1. Obtain a 5-mL venous blood sample from a fasting patient. Serum is best to use. Observe standard precautions.
Place specimen in a biohazard bag.
2. Check with your laboratory for specific challenge protocols for stimulation tests such as insulin-induced
hypoglycemia, arginine transfusion, glucagon infusion, L-dopa, and propranolol with exercise.
Clinical Implications
1. Increased hGH levels are associated with the following conditions:
a. Pituitary gigantism
b. Acromegaly
c. Laron's dwarfism (hGH resistant)
d. Ectopic GH secretion
e. Uncontrolled diabetes mellitus
2. Decreased hGH levels are associated with the following conditions:
a. Pituitary dwarfism
b. Hypopituitarism
c. Adrenocortical hyperfunction
3. Following stimulation testing, no response (or an inadequate response) is seen in hGH and ACTH deficiencies
(hypopituitarism).
a. Blood glucose must fall to <40 mg/dL (<2.2 mmol/L)
b. Adrenergic signs must be observed.
4. Following suppression tests, there is no or incomplete suppression in persons with gigantism or acromegaly.
a. Paradoxical rises in hGH may occur in patients with acromegaly.
b. Partial suppression is sometimes seen in anorexia nervosa.
c. In children, rebound-stimulation effect may be seen 2 to 5 hours following administration of glucose
(suppression test).

Interfering Factors
1. Increased levels are associated with the use of oral contraceptives, estrogens, arginine, glucagon, levodopa, low
glucose, and insulin.
2. Levels will rise to 15 times normal by the second day of starvation; levels also rise after deep sleep, stress,
exercise, and anorexia.
3. Decreased levels are associated with obesity and the use of corticosteroids.
4. Many drugs interfere with test results (see Appendix J).
5. Recently administered radioisotopes interfere with test results.
Interventions
Pretest Patient Care
1. Explain test purpose and blood-drawing procedure.
2. Remind patient that fasting from food for 8 to 10 hours is required; water is permitted. For accurate levels, the
patient should be free of stress and at complete rest in a quiet environment for at least 30 minutes before specimen
collection.
3. Note the patient's physiologic state (eg, feeding, fasting, sleep, and/or activity) at testing in the health care record.
4. For stimulation tests, collect one tube before stimulation and at timed intervals (eg, 10, 20, 30, 45, and 60 minutes)
after stimulation. For suppression tests, collect one tube before suppression and 30, 60, 90, and 120 minutes after
suppression.
5. Remember that for initial testing of hGH deficiency, a vigorous exercise test is considered to be a simple, risk-free
screening test, especially for children.
6. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results and monitor appropriately. A glucose challenge test may be indicated for follow-up.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Parathyroid Hormone Assay; Parathyrin; Parathormone (PTH-C-Terminal)
Parathormone (PTH), a polypeptide hormone produced in the parathyroid gland, is one of the major factors in the
regulation of calcium concentration in extracellular fluid. Three molecular forms of PTH exist: intact (also called native or
glandular hormone); multiple N-terminal fragments; and C-terminal fragments.
This test studies altered calcium metabolism, establishes a diagnosis of hyperparathyroidism, and distinguishes
nonparathyroid from parathyroid causes of hypercalcemia. A decrease in the level of ionized calcium is the primary
stimulus for PTH secretions, whereas a rise in calcium inhibits secretions. This normal relation is lost in hyperthyroidism,
and PTH will be inappropriately high in relation to calcium. Acute changes in secretory activity are better reflected by the
PTH, N-terminal assay. PTH and N-terminal levels are usually decreased when hypercalcemia is due to neoplastic
secretions (prostaglandins). PTH and N-terminal levels may be a more reliable indication of secondary
hyperparathyroidism in patients with renal failure. Creatinine level is determined concurrently with all PTH assays to
determine kidney function and for meaningful interpretation of results.
Reference Values
Normal N-terminal: 8–24 pg/mL or 8–24 ng/L Intact molecule: 10–65 pg/mL or 10–65 ng/L Calcium: 8.5–10.9 mg/dL
(calcium must be tested to properly interpret results) C-terminal (biomolecule): 50–330 pg/mL or 50–330 ng/L
Procedure
1. Obtain a 10-mL venous blood sample from a patient who has fasted for 10 hours. Collect the sample in chilled vials
and keep on ice. Observe standard precautions. Serum or EDTA is used.
2. Immediately take specimen to the laboratory and centrifuge at 4°C after blood has clotted.
Clinical Implications
1. Increased PTH values occur with:
a. Primary hyperparathyroidism
b. Pseudohyperparathyroidism when there is a primary defect in renal tubular responsiveness to PTH (secondary
hyperparathyroidism)
c. Hereditary vitamin D dependency
d. Zollinger-Ellison syndrome
e. Spinal cord injury
2. Decreased PTH values occur in the following conditions:
a. Hypoparathyroidism (Graves' disease)
b. Nonparathyroid hypercalcemia
c. Secondary hypoparathyroidism (surgical)
d. Magnesium deficiency
e. Sarcoidosis
f. Hyperthyroidism
g. DiGeorge's syndrome
3. Increased PTH–N-terminal values occur in the following conditions:
a. Primary hyperparathyroidism
b. Secondary hyperparathyroidism (more reliable than PTH-C-terminal)

4. Decreased PTH–N-terminal values occur in the following conditions:
a. Hypoparathyroidism
b. Nonparathyroidism hypercalcemia
c. Aluminum-associated osteomalacia
d. Severely impaired bone mineralization
5. Increased PTH–C-terminal values occur in the following conditions:
a. Primary hyperparathyroidism (very specific for)
b. Some neoplasms with elevated calcium
c. Renal failure (even if parathyroid disease is absent)
6. Decreased PTH–C-terminal values occur in the following conditions:
a. Hypoparathyroidism
b. Nonparathyroid hypercalcemia
Interfering Factors
1.
2.
3.
4.
5.

Elevated blood lipids and hemolysis interfere with test methods.
Milk-alkali syndrome may falsely lower PTH levels (Burnett's syndrome).
Recently administered radioisotopes (see Appendix J) will alter results.
Vitamin D deficiency will increase PTH levels.
Many drugs alter results; phosphates raise PTH levels up to 125%, and vitamin A and D overdoses decrease PTH
levels (see Appendix J).

Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Remind patient that fasting for at least 10 hours is required. Draw blood by 8:00 a.m. because of circadian rhythm
changes. Concurrently, also draw blood for testing of calcium level.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results and monitor appropriately for calcium imbalance and hypoparathyroidism or
hyperparathyroidism.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Somatomedin C (SM-C); Insulin-like Growth Hormone
Somatomedin C, a polypeptide hormone produced by the liver and other tissues, mediates growth hormone activity and
glucose metabolism. It is carried in the blood and is bound to a protein carrier that prolongs its half-life.
This test is used to monitor the growth of children as well as to diagnose acromegaly and hypopituitarism. Normal
somatomedin C results rule out a deficiency of growth hormone. Testing of somatomedin C is preferable to growth
hormone tests because its levels are more constant. Somatomedin C is also a reliable nutrition index, having a low value
for anorexia or malnutrition.
Reference Values
Normal See Table 6.8.
Table 6.8 Values for Somatomedin C
Male
Age (yr) (ng/mL) (nmol/L)

Female
(ng/mL) (nmol/L)

0–5
0–103 0–13.5
0–112 0–14.7
6–8
2–118 0.2–15.4 5–128 0.6–16.8
9–10
15–148 2.0–19.4 24–158 3.1–20.7
11–13 55–216 7.2–28.3 65–226 8.5–29.6
14–15 114–232 14.9–30.4 124–242 16.2–31.7
16–17 84–221 11.0–28.9 94–231 12.3–30.3
18–19 56–177 7.3–23.2 66–186 8.6–24.4
20–24 75–142 9.8–18.6 64–131 8.4–17.2
25–50 60–122 7.9–16.0 50–112 6.6–14.7
Note: levels slowly decrease as person ages.

Procedure
1. Be aware that it is preferred that the patient be fasting. Obtain a 5-mL plasma venous blood sample using EDTA
anticoagulant. Serum may also be used. Observe standard precaution. Place specimen in a biohazard bag.
2. Chill blood-drawing tubes before and place on ice immediately after obtaining specimen. Spin the sample in a

refrigerated centrifuge. Freeze if not testing immediately.
Clinical Implications
1. Increased somatomedin C levels are associated with the following conditions:
a. Acromegaly (some cases), gigantism
b. Hypoglycemia associated with non–islet cell tumors
c. Hepatoma
d. Wilms' tumor
e. Precocious puberty
2. Decreased somatomedin C levels are associated with the following conditions:
a. Dwarfism (short stature)
b. Hypopituitarism
c. Hypothyroidism
d. Puberty delay
e. Laron's dwarfism
f. Cirrhosis of liver and other hepatocellular diseases
g. Malnutrition and anorexia
h. Diabetes mellitus (diabetic retinopathy)
i. Emotional deprivation syndrome (maternal deprivation)
Interfering Factors
1. Somatomedin C levels are increased 2 to 3 times in pregnancy.
2. Somatomedin C levels are decreased in the following conditions:
a. Acute illness
b. Normal aging
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. Fasting is not required.
2. Do not administer radioisotopes within 1 week of testing.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results and monitor appropriately for abnormal growth and development.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

NOTE
Because SM-C is decreased with malnutrition, it can be used to monitor therapy for food deprivation.

FERTILITY TESTS
Fertility denotes the ability of a man and woman to reproduce; conversely, infertility denotes the lack of fertility—an
involuntary reduction in the ability to produce children. When a couple has been engaging in regular, unprotected sexual
intercourse for at least 1 year without conceiving, the couple is considered infertile. In about one third of cases, a male
factor is the predominant cause; in another one third, the female factor predominates; and in another one third, no cause
is found in either partner.
The workup for infertility starts with a complete history and physical exam for both the woman and the man, including
their sexual history. A rational approach is to put each partner through a series of tests that generally uncover a vast
majority of the contributing factors of infertility. These tests usually take 2 to 3 months to complete.
Standard pretest and posttest care for couples undergoing fertility testing includes the following: Provide information and
support. Be sensitive to the couple's need for privacy and confidentiality. Maintain a communication network about new
procedures, tests, and treatments. Help couples deal with feelings of sadness and loss. Assist couples to deal with the
effects of stress and the financial burden during the diagnostic process. Assist couples in arranging work and testing
schedules with the least amount of disruption for the couple. Arrange for counseling with experts who understand the
different ways infertility affects someone's life.
Tests include evaluation of amenorrhea, anovulation, sperm count (angiosperm, oligospermia), hormone testing,
hysterosalpingogram, laparoscopy, hysteroscopy, fertiloscopy, semen analysis, postcoital test, endometrial biopsy, and
chromosome karyotype to exclude Kallmann's syndrome. Hormone testing rules pregnancy in or out (eg, chorionic
gonadotropin, prolactin, luteinizing hormone [LH], follicle-stimulating hormone [FSH], thyroid-stimulating hormone [TSH],
postcoital test, and antisperm antibodies). Also see estrogen testing in Chapter 3.

NOTE
A postcoital examination is done to assess cervical mucus and competent sperm motility. A specimen is obtained from
the endocervical canal within 2 to 12 hours of coitus and is examined for viscosity (stretching to 6 cm is normal) and for
ferning effect of estrogen. The presence of >50% sperm confirms male competence.
Chorionic Gonadotropin; Human Chorionic Gonadotropin (hCG) ß Subunit; Pregnancy Test
The glycoprotein hormones hCG, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and thyroid-stimulating
(TSH) are composed of two different subunits. The a subunit is similar in all of the glycoprotein hormones, and the ß
subunit is unique to each hormone. Highly specific assays allow hCG to be measured in the presence of other
glycoprotein hormones. The increased sensitivity of the ß-hCG test detects pregnancy as early as 6 to 10 days after
implantation of the oocyte. A variety of poorly differentiated or undifferentiated neoplasms may produce ectopic chorionic
gonadotropin. Assay for total hCG, both a and ß subunits, or ß-hCG may detect ectopic tumors (eg, choriocarcinoma,
hydatidiform mole, germinal testicular tumors). In these neoplasms, hCG is usually the product of syncytiotrophoblastic
cells.
This qualitative test detects normal pregnancy. It is quicker but less sensitive (sensitivity, 20–50 mIU/mL) than the
quantitative test. This test can be expected to become positive within 3 days of implantation (ie, just after the first missed
menstrual period). Cross-reactivity with LH is low, and false-positive results are rare. Occasionally, a patient with very
high LH levels will give a borderline reaction. The qualitative test is usually done using urine.
The quantitative ß-hCG test is used for nonroutine detection of hCG. It is sensitive to 1 to 3 mIU/mL. This test provides
the most sensitive and specific test for the detection of early pregnancy, estimation of gestational age, and diagnosis of
ectopic pregnancy or threatened spontaneous abortion. This test is also useful in the workup and management of
testicular tumors. High levels may be found in choriocarcinoma, embryonal cell carcinoma, and ectopic pregnancy. hCG
levels are extremely useful in following germ cell neoplasms that produce hCG, especially trophoblastic neoplasms.
There is little cross-reactivity with LH.
Reference Values
Normal Qualitative (for routine pregnancy tests): urine or serum negative (not pregnant) Quantitative (for nonroutine
detection of hCG) Men: <5.0 IU/L or mIU/mL Nonpregnant women: <5.0 IU/L or mIU/mL Pregnant women: 1 week of
gestation: 5–50 mIU/mL or IU/L 2 weeks of gestation: 50–500 mIU/mL or IU/L 3 weeks of gestation: 100–10,000 mIU/mL
or IU/L 4 weeks of gestation: 1080–30,000 mIU/mL or IU/L 6–8 weeks of gestation: 3500–115,000 mIU/mL or IU/L 12
weeks of gestation: 12,000–270,000 mIU/mL or IU/L 13–16 weeks of gestation: up to 200,000 mIU/mL or IU/L 17–40
weeks of gestation: gradual fall to 4000 mIU/mL or IU/L
Procedure
1. Obtain a 5-mL venous blood sample. Serum is used for the test.
2. Observe standard precautions. Place specimen in a biohazard bag.
3. Urine may be used for the qualitative test. First morning specimen is recommended.
Clinical Implications
1. Increased hCG values occur in the following conditions:
a. Pregnancy
b. Successful therapeutic insemination and in vitro fertilization
c. Hydatidiform mole
d. Choriocarcinoma
e. Seminoma
f. Ovarian and testicular teratomas
g. Ectopic pregnancy
h. Certain neoplasms of the lung, stomach, and pancreas
i. Down syndrome (trisomy 21), mid-trimester elevation
2. Decreased hCG values occur in:
a. Threatened spontaneous abortion
b. Ectopic pregnancy
c. Trisomy 18, decrease at mid-trimester
Interfering Factors
1. Lipemia, hemolysis, and radioisotopes administered within 1 week of testing may affect results.
2. Test results can be positive up to 1 week after complete abortion.
3. False-negative and false-positive results can be caused by many drugs (see Appendix J).

Clinical Alert
Because there is great variability in hCG concentration among pregnant women, a single test determination cannot be
used to accurately date the gestational age. Serial determinations may be helpful when abnormal pregnancy is
suspected. Serial values do not double every 48 hours. In normal pregnancy, the hCG level doubles every 48 hours
during the first 6 weeks of gestation.
Interventions
Pretest Patient Care

1. Explain test purpose and procedure.
2. Determine and record date of last menstrual period in women.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Resume normal activities.
2. Interpret test results and counsel appropriately for pregnancy or gestational problems.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Follicle-Stimulating Hormone (FSH); Luteinizing Hormone (LH)
FSH and LH are glycoprotein pituitary hormones produced and stored in the anterior pituitary. They are under complex
regulation by hypothalamic gonadotropin-releasing hormone and by gonadal sex hormones (estrogen and progesterone
in females and testosterone in males). FSH acts on granulosa cells of the ovary and Sertoli's cells of the testis, and LH
acts on Leydig's (interstitial) cells of the gonads. Normally, FSH increases occur at earlier stages of puberty, 2 to 4 years
before LH reaches comparable levels. In males, FSH and LH are necessary for spermatozoa development and
maturation. In females, follicular formation in the early stages of the menstrual cycle is stimulated by FSH; then the
midcycle surge of LH causes ovulation of the FSH-ripened ovarian follicles to occur.
This test measures the gonadotropic hormones FSH and LH and may help determine whether a gonadal deficiency is of
primary origin or is due to insufficient stimulation by the pituitary hormones.
Evaluation of FSH supports other studies related to determining causes of hypothyroidism in women and endocrine
dysfunction in men. In primary ovarian failure or testicular failure, FSH levels are increased. Measuring the levels of FSH
and LH is of value in studying children with endocrine problems related to precocious puberty.
In the case of anovulatory fertility problems, the presence or absence of the midcycle peak can be established through a
series of daily blood specimens.
Reference Values
Normal See Table 6.9.
Table 6.9 Values for Luteinizing and Follicle-Stimulating Hormones
Luteinizing Hormone (LH)

(mIU/L)

or

(IU/L)

Follicle-Stimulating Hormone
(FSH)
(mIU/L)

or

(IU/L)

Female
Follicular
1.37–9.9
1.37–9.9
1.68–15
1.68–15
Ovulatory peak
6.17–17.2
6.17–17.2
21.9–56.6
21.9–56.6
Luteal
1.09–9.2
1.09–9.2
0.61–16.3
0.61–16.3
Postmenopausal
19.3–100.6
19.3–100.6
14.2–52.3
14.2–52.3
Male
1.42–15.4
1.42–15.4
1.24–7.8
1.24–7.8
Note: contact your laboratory for reference values in infants and children. Normal values may vary with method of testing
and units used.

Procedure
1. Obtain a 5-mL venous blood sample. Serum is needed for the test. Place specimen in a biohazard bag.
2. In women, record the date of last menstrual period.
3. Remember that it is important to measure both FSH and LH.

Clinical Alert
Sometimes multiple blood specimens are necessary because of episodic releases of FSH from the pituitary gland. An
isolated sample may not indicate the actual activity; therefore, pooled blood specimens or multiple single blood
specimens may be required.
Clinical Implications
1. Decreased FSH levels occur in the following conditions:
a. Feminizing and masculinizing ovarian tumors when FSH production is inhibited because of increased estrogen
secretion.
b. Failure of hypothalamus to function properly (Kallmann's syndrome)
c. Pituitary LH or FSH deficiency
d. Neoplasm of testes or adrenal glands that influence secretion of estrogens or androgens
e. Polycystic ovarian disease
f. Hemochromatosis
g. Anorexia

2. Decreased FSH and LH occur in pituitary or hypothalamic failure.
3. Increased FSH levels occur in the following conditions:
a. Turner's syndrome (ovarian dysgenesis); about 50% of patients with primary amenorrhea have Turner's
syndrome.
b. Hypopituitarism
c. Sheehan's syndrome
d. Precocious puberty, either idiopathic or secondary to a CNS lesion
e. Klinefelter's syndrome
f. Castration
g. Alcoholism
h. Menopause and menstrual disorders
4. Both FSH and LH are increased in the following conditions:
a. Hypogonadism
b. Complete testicular feminization syndrome
c. Gonadal failure
d. Congenital absence of testicle or testicles (anorchia)
e. Menopause
5. Elevated basal LH with an LH/FSH ratio >2 and some increase of ovarian androgen in an essentially nonovulatory
adult woman is presumptive evidence of Stein-Leventhal syndrome (polycystic ovary syndrome).
Interfering Factors
1.
2.
3.
4.
5.

Recently administered radioisotopes
Hemolysis of blood sample
Estrogens or oral contraceptives, testosterone
Several drugs affect test outcomes; see Appendix J.
Pregnancy

Interventions
Pretest Patient Care
1. Instruct the patient regarding test purpose and procedure.
2. For women, record date of last menstrual period.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test outcomes and counsel appropriately.
2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Prolactin (hPRL)
Prolactin is a pituitary hormone essential for initiating and maintaining lactation. The gender difference in prolactin does
not occur until puberty, when increased estrogen production results in higher prolactin levels in females. Circadian
changes in prolactin concentration in adults are marked by episodic fluctuation and a sleep-induced peak in the early
morning hours.
This test may be helpful in the diagnosis, management, and follow-up of a prolactin-secreting tumor accompanied by
secondary amenorrhea or galactorrhea, hyperprolactinemia, and infertility. It is also useful in the management of
hypothalamic disease and in monitoring the effectiveness of surgery, chemotherapy, and radiation treatment of
prolactin-secreting tumors.
Reference Values
Normal Nonpregnant women: 0–23 ng/mL or 0–23 µg/L Pregnant women: 34–386 ng/mL or 34–386 µg/L by third
trimester Men: 0–20 ng/mL or 0–20 µg/L Children: 3.2–20 ng/mL or 3.2–20 µg/L
Procedure
1. Ensure that the patient fasts for 12 hours before testing. Obtain a 5-mL venous blood sample. Serum is used.
2. Procure specimens in the morning, between 8:00 and 10:00 a.m. Draw in chilled tubes keep specimen on ice.
3. Observe standard precautions. Place specimen in a biohazard bag.
Clinical Implications
1. Increased prolactin values are associated with the following conditions:
a. Galactorrhea or amenorrhea
b. Diseases of the hypothalamus and pituitary (acromegaly)
c. Prolactin-secreting pituitary tumors
d. Chiari-Frommel syndrome
e. Ectopic production of prolactin from tumors, carcinoma, and leukemia
f. Hypothyroidism (primary)
g. Polycystic ovary syndrome
h. Anorexia nervosa
i. Insulin-induced hypoglycemia
j. Adrenal insufficiency
2. Decreased prolactin values are found in the following conditions:

a. Sheehan's syndrome (pituitary apoplexy)
b. Idiopathic hypogonadotropic hypogonadism

NOTE
The only result of prolactin deficiency in pregnancy is the absence of postpartum lactation.
Interfering Factors
1. Increased values are associated with newborns, pregnancy, postpartum period, stress, exercise, sleep, nipple
stimulation, and lactation (breast feeding).
2. Drugs (eg, estrogens, methyldopa, phenothiazines, opiates) may increase values. See Appendix J for other drugs.
3. Dopaminergic drugs inhibit prolactin secretion. Administration of L-dopa can normalize prolactin levels in
galactorrhea, hyperprolactinemia, and pituitary tumor. See Appendix J for other drugs.
4. Increased levels are found in cocaine abuse, even after withdrawal from cocaine.

Clinical Alert
Levels >200 ng/mL or >200 µg/L in a nonlactating female indicate a prolactin-secreting tumor; however, a normal
prolactin level does not rule out pituitary tumor.
Interventions
Pretest Patient Care
1. Explain test purpose. Fasting is required. Obtain blood specimen between 8:00 and 10:00 a.m. (3–4 hours after
patient has awakened). Obtain history of leakage from the breast in nonpregnant females.
2. Have patient avoid stress, excitement, or stimulation; venipuncture itself can sometimes elevate prolactin levels.
3. If possible, discontinue all prescribed medications for 2 weeks before test.
4. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test outcome and counsel regarding repeat testing to monitor treatment. Magnetic resonance imaging may
be indicated.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Progesterone
Progesterone, a female sex hormone, is primarily involved in the preparation of the uterus for pregnancy and its
maintenance during pregnancy. The placenta begins producing progesterone at 12 weeks of gestation. Progesterone
level peaks in the midluteal phase of the menstrual cycle. In nonpregnant women, progesterone is produced by the
corpus luteum. Progesterone is the single best test to determine whether ovulation has occurred.
This test is part of a fertility study to confirm ovulation, evaluate corpus luteum function, and assess risk for early
spontaneous abortion. Testing of several samples during the cycle is necessary. Ovarian production of progesterone is
low during the follicular (first) phase of the menstrual cycle. After ovulation, progesterone levels rise for 4 to 5 days and
then fall. During pregnancy, there is a gradual increase from week 9 to week 32 of gestation, often to 100 times the level
in the nonpregnant woman. Levels of progesterone in twin pregnancy are higher than in a single pregnancy. Serum
progesterone levels used with ß-hCG assist in differentiating normal uterine pregnancy from abnormal uterine or ectopic
pregnancy.
Reference Values
Normal Men: <1.0 ng/mL or <3.2 nmol/L Women: Prepubertal: 0.1–0.3 ng/mL or 0.3–1.0 nmol/L Follicular: 0.1–0.7 ng/mL
or 0.5–2.3 nmol/L Luteal: 2–25 ng/mL or 6.4–79.5 nmol/L First trimester: 10–44 ng/mL or 32.6–140 nmol/L Second
trimester: 19.5–82.5 ng/mL or 62.0–262 nmol/L Third trimester: 65–290 ng/mL or 206.7–728 nmol/L
Procedure
1. Obtain a venous blood sample. Serum is needed for test. Observe standard precautions. Place specimen in a
biohazard bag.
2. Remember that the test request should include gender, day of last menstrual period, and length of gestation in
women.
3. Be aware that a ß-hCG may be ordered at the same time.
4. Remember that urine levels may be done, but serum is preferred.
Clinical Implications
1. Increased progesterone levels are associated with the following conditions:
a. Congenital adrenal hyperplasia
b. Lipid ovarian tumor
c. Molar pregnancy
d. Chorionepithelioma of ovary
2. Decreased progesterone levels are associated with the following conditions:
a. Threatened spontaneous abortion
b. Galactorrhea-amenorrhea syndrome (primary or secondary hypogonadism)

c. Short luteal phase syndrome
Interfering Factors
1.
2.
3.
4.

See Appendix J for drugs that affect test outcomes.
Critical value: levels <10 ng/mL or <32 nmol/L are associated with abnormal pregnancy outcome.
5–10 ng/mL or 16–32 nmol/L: pathologic pregnancy
Progesterone <5 ng/mL or <16 nmol/L: nonviable

Interventions
Pretest Patient Care
1. Explain test purpose and procedure. Note date of last menstrual period/length of gestation.
2. Do not administer radioisotopes within 1 week before the test.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results, and counsel and monitor appropriately regarding fertility and pregnancy outcome.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Testosterone, Total and Free
Testosterone is responsible for the development of male secondary sexual characteristics. It is secreted by the adrenal
glands and testes in men and by the adrenal glands and ovaries in women. Excessive production induces premature
puberty in men and masculinity in women. Testosterone exists in serum as both unbound (free) fractions and bound
fractions to albumin: sex hormone–binding globulin (SHBG) and testosterone-binding globulin. Unbound (free)
testosterone is the active portion. Testosterone levels undergo large and rapid fluctuations; levels peak in early morning
in males. Females show a cyclic elevation 1 to 2 days midcycle.
Testosterone measurements in men assess hypogonadism, pituitary gonadotropin function, impotency, and
cryptorchidism; these measurements are also useful in the detection of ovarian tumors and hirsutism in women. In
prepubertal boys, they can assess special precocity. This test may be part of a fertility workup in association with chronic
anovulation caused by polycystic ovary syndrome.
Reference Values
Normal Total testosterone Men: 270–1070 ng/dL or 9–38 nmol/L (values in elderly men diminish moderately) Women:
15–70 ng/dL or 0.52–2.4 nmol/L Pregnant women: 3–4 times normal Postmenopausal women: 8–35 ng/dL or 0.3–1.2
nmol/L (half of normal) Children: 2–20 ng/dL or 0.07–0.7 nmol/L (depends on age, sex, and onset of puberty) Free
testosterone Men: 50–210 pg/mL or 174–729 pmol/L Women: 1.0–8.5 pg/mL or 3.5–29.5 pmol/L Children: Boys: 0.1–3.2
pg/mL or 0.3–11.1 pmol/L Girls: 0.1–0.9 pg/mL or 0.3–3.1 pmol/L Puberty: Boys: 1.4–156 pg/mL or 4.9–541 pmol/L Girls:
1.0–5.2 pg/mL or 3.5–18.0 pmol/L
Procedure
1. Obtain a 5-mL venous blood sample; serum is preferred. Observe standard precautions. Place specimen in a
biohazard bag.
2. Indicate age and gender on laboratory requisition.
Clinical Implications
1. Males: decreased total testosterone levels occur in the following conditions:
a. Hypogonadism (pituitary failure)
b. Klinefelter's syndrome
c. Hypopituitarism (primary and secondary)
d. Orchidectomy
e. Hepatic cirrhosis
f. Down syndrome
g. Delayed puberty
2. Males: decreased free testosterone levels occur in hypogonadism and elderly men.
3. Males: increased total testosterone levels occur in the following conditions:
a. Hyperthyroidism
b. Syndromes of androgen resistance
c. Adrenal tumors
d. Precocious puberty and adrenal hyperplasia in boys
4. Females: increased total testosterone levels are associated with the following conditions:
a. Adrenal neoplasms
b. Ovarian tumors, benign or malignant (virilizing)
c. Trophoblastic disease during pregnancy
d. Idiopathic hirsutism
e. Hilar cell tumor
5. Females: increased free testosterone levels are associated with the following conditions:
a. Female hirsutism
b. Polycystic ovaries

c. Virilization

Clinical Alert
1. Testosterone levels are normal in cryptorchidism, azoospermia, and oligospermia.
2. In general, there appears to be little advantage in doing urine testosterone measurements compared with (or in
addition to) serum measurements; the serum test is recommended.
3. Panic value: total testosterone >200 ng/dL or >694 pmol/L in females indicates androgenic tumors of the adrenal
or ovaries, especially with severe hirsutism.
Interfering Factors
1. Alcoholism in males decreases testosterone levels.
2. Estrogen therapy increases testosterone levels (see Appendix J).
3. Many drugs, including androgens and steroids, decrease testosterone levels (see Appendix J).
Interventions
Pretest Patient Care
1.
2.
3.
4.

Explain test purpose and procedure. Draw blood at 7:00 a.m. for highest levels.
Draw multiple pooled samples at different times throughout the day if necessary for more reliable results.
Do not administer radioisotopes within 1 week before test.
Follow guidelines in Chapter 1 regarding safe, effective, informed pretest care.

Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results and counsel appropriately regarding hormone dysfunction.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

ENZYME TESTS
Acid Phosphatase; Prostatic Acid Phosphatase (PAP)
Acid phosphatases are enzymes that are widely distributed in tissues, including the bone, liver, spleen, kidney, red blood
cells, and platelets. However, their greatest diagnostic importance involves the prostate gland, where acid phosphatase
activity is 100 times higher than in other tissues. Immunochemical methods are highly specific for determining the
prostatic fraction; however, because PAP is not elevated in early prostatic disease, this test is not recommended for
screening.
This test monitors the effectiveness of treatment of cancer of the prostate. Elevated levels of acid phosphatase are seen
when prostate cancer has metastasized beyond the capsule to the other parts of the body, especially the bone. Once the
carcinoma has spread, the prostate starts to release acid phosphatase, resulting in an increased blood level. The
prostatic fraction procedure specifically measures the concentration of prostatic acid phosphatase secreted by cells of
the prostate gland. Acid phosphatase is also present in high concentration in seminal fluid. Tests for presence of this
enzyme on vaginal swabs may be used to investigate rape.
Reference Values
Normal 2.5–3.7 ng/mL or 2.5–3.7 µg/L
Procedure
1. Obtain a 5-mL venous blood sample. Serum may be used, if test is done within 1 hour. EDTA plasma is preferred to
stabilize acid phosphatase.
2. Remember that morning is recommended because diurnal variation exists.
3. Place specimen in a biohazard bag, transport to lab immediately, and place on ice.
Clinical Implications
1. A significantly elevated acid phosphatase value is almost always indicative of metastatic cancer of the prostate. If
the tumor is successfully treated, this enzyme level will drop within 3 to 4 days after surgery or 3 to 4 weeks after
estrogen administration.
2. Moderately elevated values also occur in the absence of prostate carcinoma in the following conditions:
a. Niemann-Pick disease
b. Gaucher's disease
c. Prostatitis (benign prostatic hypertrophy)
d. Urinary retention
e. Any cancer that has metastasized to the bone
f. Myelocytic leukemia
Interfering Factors
1. Various drugs may cause increased and decreased PAP levels.
2. Palpation of the prostate gland and prostate biopsy before testing causes increases in PAP levels.

3. Transurethral resection of the prostate (TURP) and bladder catheterization cause increased levels.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. No palpation of or procedures on the prostate gland and no rectal examinations should be performed 2 to 3 days
before test.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results and counsel appropriately regarding repeat testing. When elevated values are present,
retesting and biopsy are considered.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Prostate-Specific Antigen (PSA)
Prostate-specific antigen (PSA) is functionally and immunologically distinct from prostatic acid phosphatase. PSA is
localized in both normal prostatic epithelial cells and prostatic carcinoma cells. PSA has proved to be the most
prognostically reliable marker for monitoring recurrence of prostatic carcinoma; however, this test does not have the
sensitivity or specificity to be considered an ideal tumor marker. PSA detects incidental as well as aggressive
carcinomas.
The most useful approach to date may be age-specific PSA reference ranges, which are based on the concept that blood
PSA concentration is dependent on patient age. The increase in PSA with advancing age is attributed to four major
factors: prostate enlargement, increasing inflammation, presence of microscopic but clinically insignificant cancer, and
leakage of PSA into the serum ( Table 6.10).

Table 6.10 Suggested Age-Specific PSA Reference Ranges
PSA Range
Age (yr)

(ng/mL) (µg/L)

40–49
0.0–2.5 0.0–2.5
50–59
0.0–3.5 0.0–3.5
60–69
0.0–4.5 0.0–4.5
70–79
0.0–6.5 0.0–6.5
From Oesterling JE, Jacobson SJ, Chute CG, et al.: Serum prostate-specific antigen in a community-based population of
healthy men: establishment of age-specific reference ranges. JAMA 270(7): 860–864, 1993

Testing for both PSA and PAP increases detection of early prostate cancer. PSA testing determines the effectiveness of
therapy for prostate cancer and is used as an early indicator of prostate cancer recurrence. The greatest value of PSA is
as a marker in the follow-up of patients at high risk for disease progression.
PSA lacks sensitivity and specificity to be used alone as a screening test for prostatic carcinoma, but in conjunction with
a digital rectal exam, the detection rate of prostatic carcinoma is greatly increased.
Reference Values
Normal Men: 0–4.0 ng/mL or 0–4.0 µg/L
Procedure
1. Obtain a 5-mL venous blood sample. Serum is needed.
2. Observe standard precautions. Place specimen in a biohazard bag.
3. Record patient's age.
Clinical Implications
1. PSA increases occur in prostate cancer (80% of patients).
2. Patients with benign prostatic hypertrophy often demonstrate values between 4.0 and 8.0 ng/mL (4.0–8.0 µg/L).
Results between 4.0 and 8.0 ng/mL (4.0–8.0 µg/L) may represent benign prostatic hypertrophy or possible cancer
of the prostate. Results >8.0 ng/mL or >8.0 µg/L are highly suggestive of prostatic cancer.
3. Increases to >4.0 ng/mL or >4.0 µg/L have been reported in about 8% of patients with no prostatic malignancies
and no benign diseases.
4. If a prostate tumor is completely and successfully removed, no antigen will be detected.
Interfering Factors

1. Transient increases in PSA occur following prostate palpation or rectal examination.
2. Increased with urinary retention.
3. Recent exposure to radioisotopes causes test interference.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Do not schedule any prostatic examinations, including rectal examination, prostate biopsy, or TURP, for 1 week
before the blood test is performed.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results, and monitor and counsel as appropriate for response to treatment and progression or
remission of prostate cancer.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Clinical Alert
1. PSA is not a definitive diagnostic marker to screen for carcinoma of the prostate because it is also found in men
with benign prostatic hypertrophy.
2. Digital rectal examination (DRE) is recommended by the American Cancer Society as the primary test for
detection of prostatic tumor. Recent studies indicate that serum PSA may offer additional information. PSA should
be used in conjunction with DRE.
3. The value of prostatic cancer screening remains controversial in terms of patient morbidity and longevity
outcomes.
Alanine Aminotransferase (Aminotransferase, ALT); Serum Glutamic-Pyruvic Transaminase (SGPT)
ALT is an enzyme. High concentrations occur in the liver, and relatively low concentrations are found in the heart,
muscle, and kidney.
This test is primarily used to diagnose liver disease and to monitor the course of treatment for hepatitis, active
postnecrotic cirrhosis, and the effects of later drug therapy. ALT is more sensitive in the detection of liver disease than in
biliary obstruction. ALT also differentiates between hemolytic jaundice and jaundice due to liver disease.
Reference Values
Normal Adults (adult levels are reached by 6 months): 10–35 U/L or 0.17–0.60 µkat/L (males slightly higher) Males:
10–40 U/L or 0.17–0.68 µkat/L Females: 7–35 U/L or 0.12–0.60 µkat/L Newborns: 13–45 U/L or 0.22–0.77 µkat/L ALT
values are slightly higher in males and black persons. Normal values vary with testing method. Check with your
laboratory for reference values.
Procedure
1. Obtain a 5-mL venous blood sample. Serum is needed for the test. Observe standard precautions. Place specimen
in a biohazard bag.
2. Avoid hemolysis during collection of the specimen. (ALT activity is 6 times higher in RBCs.)
Clinical Implications
1. Increased ALT levels are found in the following conditions:
a. Hepatocellular disease (moderate to high increase)
b. Alcoholic cirrhosis (mild increase)
c. Metastatic liver tumor (mild increase)
d. Obstructive jaundice or biliary obstruction (mild increase)
e. Viral, infectious, or toxic hepatitis (30–50 times normal)
f. Infectious mononucleosis
g. Pancreatitis (mild increase)
h. Myocardial infarction, heart failure
i. Polymyositis
j. Severe burns
k. Trauma to striated muscle
l. Severe shock
2. Aspartate transaminase (AST)/ALT comparison:
a. Although the AST level is always increased in acute MI, the ALT level does not always increase unless there is
also liver damage.
b. The ALT is usually increased more than the AST in acute extrahepatic biliary obstruction.
c. The AST/ALT ratio is high in alcoholic liver disease; the ALT is more specific than AST for liver disease, but the
AST is more sensitive to alcoholic liver disease.

Clinical Alert
Critical Value
Alcohol-acetaminophen syndrome: extremely abnormal ALT/AST values are found
>9000 U/L (>153 µkat/L): this extreme level can distinguish this syndrome from alcoholic or viral hepatitis.
Interfering Factors
1.
2.
3.
4.
5.

Many drugs may cause falsely increased and decreased ALT levels (see Appendix J).
Salicylates may cause decreased or increased ALT levels.
Therapeutic heparin causes increased ALT.
Hemolysed blood causes increases in ALT.
Obesity causes increases in ALT.

Clinical Alert
There is a correlation between the presence of elevated serum ALT and abnormal antibodies to the hepatitis B virus
core antigen and hepatitis C antigen. Persons with elevated ALT levels should not donate blood.
Interventions
Pretest Patient Care
1. Explain test purpose and blood-drawing procedure.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results and monitor as appropriate for liver disease.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Alkaline Phosphatase (ALP), Total; 5'-Nucleotidase
Alkaline phosphatase is an enzyme originating mainly in the bone, liver, and placenta, with some activity in the kidney
and intestines. It is called alkaline because it functions best at a pH of 9. ALP levels are age and gender dependent. Post
puberty ALP is mainly of liver origin.
Alkaline phosphatase is used as an index of liver and bone disease when correlated with other clinical findings. In bone
disease, the enzyme level rises in proportion to new bone cell production resulting from osteoblastic activity and the
deposit of calcium in the bones. In liver disease, the blood level rises when excretion of this enzyme is impaired as a
result of obstruction in the biliary tract. Used alone, alkaline phosphatase may be misleading.
Reference Values
Normal Females: 1–12 years: <350 U/L >15 years: 25–100 U/L Males: 1–12 years: <350 U/L 12–14 yrs: <500 U/L >20
yrs: 25–100 U/L Normal values are higher in pediatric patients and in pregnancy. Values increase up to 3 times in
puberty. Check with your laboratory for reference values. Values may vary with method of testing.
Procedure
1. Obtain a 5-mL fasting venous blood sample. Serum is used for this test. Anticoagulants may not be used. Observe
standard precautions. Place specimen in a biohazard bag.
2. Refrigerate sample as soon as possible.
3. Note age and gender on test requisition.
Clinical Implications
1. Elevated levels of ALP in liver disease (correlated with abnormal liver function tests) occur in the following
conditions:
a. Obstructive jaundice (gallstones obstructing major biliary ducts; accompanying elevated bilirubin)
b. Space-occupying lesions of the liver such as cancer (hepatic carcinoma) and malignancy with liver metastasis
c. Hepatocellular cirrhosis
d. Biliary cirrhosis
e. Intrahepatic and extrahepatic cholestasis
f. Hepatitis, infectious mononucleosis, cytomegalovirus
g. Diabetes mellitus (causes increased synthesis), diabetic hepatic lipidosis
h. Chronic alcohol ingestion
i. Gilbert's syndrome
2. Bone disease and elevated ALP levels occur in the following conditions:
a. Paget's disease (osteitis deformans; levels 10 to 25 times normal)
b. Metastatic bone tumor
c. Osteogenic sarcoma
d. Osteomalacia (elevated levels help differentiate between osteomalacia and osteoporosis, in which where is no
elevation), rickets

e. Healing factors (osteogenesis imperfecta)
3. Other diseases involving elevated ALP levels include the following:
a. Hyperparathyroidism (accompanied by hypercalcemia), hyperthyroidism
b. Pulmonary and myocardial infarctions
c. Hodgkin's disease
d. Cancer of lung or pancreas
e. Ulcerative colitis, peptic ulcer
f. Sarcoidosis
g. Perforation of bowel (acute infarction)
h. Amyloidosis
i. Chronic renal failure
j. Congestive heart failure
k. Hyperphosphatasia (primary and secondary)
4. Decreased levels of ALP occur in the following conditions:
a. Hypophosphatasia (congenital)
b. Malnutrition, scurvy
c. Hypothyroidism, cretinism
d. Pernicious anemia and severe anemias
e. Magnesium deficiency
f. Milk alkali (Burnett's syndrome)
g. Celiac sprue
h. Magnesium and zinc deficiency (nutritional)

Clinical Alert
1. This test should not be done if the total alkaline phosphatase level is normal.
2. For evaluation of the biliary tract, alternative tests such as GGT, leucine aminopeptidase (LAP), and
5'-nucleotidase studies are recommended over the ALP ISO test.
3. Alkaline phosphatase isoenzymes have little value in children and adolescents because bone and liver fractions
are normally elevated.
4. In pregnancy, marked decline of the placental isoenzyme is seen with placental insufficiency and imminent fetal
demise.
Interfering Factors
1. A variety of drugs produce mild to moderate increases or decreases in ALP levels. See Appendix J for drugs that
affect outcomes.
2. Young children, those experiencing rapid growth, pregnant women, and postmenopausal women have
physiologically high levels of ALP; this level is slightly increased in older persons.
3. After IV administration of albumin, there is sometimes a marked increase in ALP for several days.
4. ALP levels increase at room temperature and in refrigerated storage. Testing should be done the same day.
5. ALP levels decrease if blood is anticoagulated.
6. ALP levels increase after fatty meals.
Interventions
Pretest Patient Care
1. Explain test purpose and blood-drawing procedure. Fasting is required.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results and monitor appropriately for liver or bone disease and evidence of tumor. Testing for
5'-nucleotidase provides supportive evidence in the diagnosis of liver disease. When ALP and 5'-nucleotidase test
results are evaluated, they provide definitive diagnosis of Paget's disease and rickets, in which high levels of ALP
accompany normal (0–5 U/L) or marginally increased 5'-nucleotidase activity. 5'-Nucleotidase is increased in liver
disease (eg, hepatic carcinoma, biliary cirrhosis, extrahepatic obstruction, metastatic neoplasia of liver).
5'-Nucleotidase level usually does not increase in skeletal disease.
3. Remember that to confirm biliary abnormality, a useful test is gamma glutamyltransferase (GGT). The GGT test is
elevated in hepatobiliary disease, but not in uncomplicated bone disease.
4. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Alkaline Phosphatase Isoenzymes (ISO)
The isoenzymes of ALP are produced in various tissues. AP-1, a 2 is produced in the liver and by proliferating blood
vessels. AP-2, ß 1 is produced by bone and placental tissue. The intestinal isoenzyme AP-3, ß 2 is present in small
quantities in group O and B individuals who are Lewis-positive secretors. Placental ALP is present in the last trimester of
pregnancy.
Any patient with an elevation of serum total alkaline phosphatase is a candidate for ALP isoenzyme study. The ALP ISO
is mainly used to distinguish between bone and liver elevations of alkaline phosphatase.
Reference Values
Normal AP-1, a 2: values (liver) reported as weak, moderate, or strong or 24–158 U/L (0.40–2.64 µkat/L) AP-2, ß 1 :

values (bone) reported as weak, moderate, or strong or 24–146 U/L (0.40–2.44 µkat/L) AP-3, ß 2 : values (intestines)
reported as weak, moderate, or strong or 0–22 U/L (0–0.36 µkat/L) AP-4: values (placental) reported as weak, moderate,
or strong. Placental AP-4 is found only in pregnant women.
Procedure
1. Obtain a 5-mL fasting venous blood sample in a plain red-topped tube or SST tube. Serum is needed. Centrifuge
blood promptly, with 30 minutes after draw.
2. Observe standard precautions. Place specimen in a biohazard bag.
3. Refrigerate if not tested immediately.
Clinical Implications
1. Liver (AP-1, a 2) isoenzymes are elevated in hepatic and biliary diseases such as the following conditions:
a. Cirrhosis (hepatic)
b. Hepatic carcinoma
c. Biliary obstruction, primary biliary cirrhosis
2. Bone (AP-2, ß 1) isoenzymes are elevated in the following conditions:
a. Paget's disease
b. Hyperparathyroidism
c. Bone cancer, rickets (all types)
d. Osteomalacia, osteoporosis
e. Malabsorption syndrome
f. Certain renal disorders (uremia bone disease or renal rickets)
3. Intestinal (AP-3, ß 2) isoenzymes are elevated in the following conditions:
a. Intestinal infarction
b. Ulcerative lesions of stomach, small intestine, and colon
c. Individuals with blood type O or B secrete intestinal isoenzymes 2 hours after a meal.
4. Placental (AP-4) isoenzymes are increased in the following conditions:
a. Pregnancy (late in third trimester to onset of labor)
b. Complications of pregnancy such as hypertension and preeclampsia
5. Placental-like isoenzymes occur in some cancers (unidentified isoenzymes):
a. Regan's isoenzyme
b. Nagao's isoenzyme
Interfering Factors Same as for alkaline phosphatase.
Interventions
Pretest Patient Care
1. See total alkaline phosphatase patient pretest care on page 389.
2. Remember that the same guidelines apply to alkaline phosphatase isoenzyme testing.
Posttest Patient Aftercare
1. See total alkaline phosphatase patient posttest aftercare on page 389.
2. Remember that the same guidelines apply to alkaline phosphatase isoenzyme testing.
Angiotensin-Converting Enzyme (ACE)
Angiotensin I is produced by the action of renin on angiotensinogen. Angiotensin I–converting enzyme (ACE) catalyzes
the conversion of angiotensin I to the vasoactive peptide angiotensin II. Angiotensin I is concentrated in the proximal
tubules.
This test is used primarily to evaluate the severity and activity of sarcoidosis. Serial determinations may be helpful in
following the clinical course of the disease with steroid treatment. It is also used in the investigation of Gaucher's
disease.
Reference Values
Normal 8–53 U/L or 0.14–0.88 µkat/L Check with your laboratory for reference values for infants and children—they are
generally higher.
Procedure
1. Obtain a 5-mL venous blood sample. Serum or heparinized plasma is used.
2. Observe standard precautions. Place specimen in a biohazard bag.
3. Freeze specimen if test is not performed immediately.
Clinical Implications
1. Increased ACE levels are associated with the following conditions:
a. Sarcoidosis (ACE levels reflect the severity of the disease, with 68% positivity in stage 1 disease, 86% in stage
2, and 92% in stage 3)
b. Gaucher's disease
c. Leprosy
d. Acute and chronic bronchitis
e. Connective tissue diseases

f. Amyloidosis
g. Pulmonary fibrosis
h. Fungal diseases and histoplasmosis
i. Untreated hyperthyroidism
j. Diabetes mellitus
k. Psoriasis
2. Decreased ACE levels occur in the following conditions:
a. Following prednisone treatment for sarcoidosis (steroid therapy)
b. Advanced lung neoplasms
c. Starvation
Interfering Factors
1.
2.
3.
4.

This test should not be done in persons <20 years of age because they normally have a very high level of ACE.
About 5% of the normal adult population have elevated ACE levels.
ACE is inhibited by EDTA anticoagulant.
Some antihypertensives may cause low ACE values.

Interventions
Pretest Patient Care
1. Explain test purpose and blood-drawing procedure.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test results and monitor as appropriate for sarcoidosis and amyloid disease.
2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Amylase and Lipase
Amylase, an enzyme that changes starch to sugar, is produced in the salivary (parotid) glands and pancreas; much lower
activities are present in the ovaries, intestines, and skeletal muscle. If there is an inflammation of the pancreas or salivary
glands, much amylase enters the blood. Amylase levels in the urine reflect blood changes by a time lag of 6 to 10 hours.
(See Amylase Excretion/Clearance, Chapter 3). Lipase is a glycoprotein that, in the presence of bile salts and colipase,
changes fats to fatty acids and glycerol. The pancreas is the major source of this enzyme. Lipase appears in the blood
following pancreatic damage at the same time amylase appears (or slightly later) but remains elevated much longer than
amylase (7 to 10 days).
Amylase and lipase tests are used to diagnose and monitor treatment of acute pancreatitis and to differentiate
pancreatitis from other acute abdominal disorders (80% of patients with acute pancreatitis will have elevated amylase
and lipase levels; lipase stays elevated longer). Lipase assay provides better sensitivity and specificity and is best used
with amylase determination.
Reference Values
Normal Amylase Newborns: 6–65 U/L or 0.1–1.1 µkat/L Adults: 25–125 U/L or 0.4–2.1 µkat/L Elderly persons (>60
years): 24–151 U/L or 0.4–2.5 µkat/L Lipase Adults: 10–140 U/L or 0.17–2.3 µkat/L Elderly persons (>60 years): 18–180
U/L or 0.30–3.0 µkat/L Normal values vary widely according to method of testing; check with your laboratory for reference
ranges. Amylase levels are low for the first 2 months of life. Most of the activity is of salivary origin. Children up to 2 years
of age have virtually no pancreatic amylase.
Procedure
1. Obtain a 5-mL venous blood sample. Serum is used. (EDTA, citrate, and oxalate anticoagulant interfere with lipase
testing.)
2. Observe standard precautions. Place specimen in a biohazard bag.
Clinical Implications
1. Greatly increased amylase levels occur in acute pancreatitis early in the course of the disease. The increase begins
in 3 to 6 hours after the onset of pain.
2. Increased amylase levels also occur in the following conditions:
a. Chronic pancreatitis, pancreatic trauma, pancreatic carcinoma, obstruction of pancreatic duct
b. Partial gastrectomy
c. Acute appendicitis, peritonitis
d. Perforated peptic ulcer
e. Cerebral trauma, shock
f. Obstruction or inflammation of salivary duct or gland and mumps
g. Acute cholecystitis (common duct stone)
h. Intestinal obstruction with strangulation
i. Ruptured tubal pregnancy and ectopic pregnancy
j. Ruptured aortic aneurysm
k. Macroamylasia
3. Decreased amylase levels occur in the following conditions:
a. Pancreatic insufficiency
b. Hepatitis, severe liver disease

c. Advanced cystic fibrosis
d. Pancreatectomy
4. Elevated lipase levels occur in pancreatic disorders (eg, pancreatitis, alcoholic and nonalcoholic; pancreatic
carcinoma).
5. Increased lipase values also are associated with the following conditions:
a. Cholecystitis
b. Hemodialysis
c. Strangulated or infarcted bowel
d. Peritonitis
e. Primary biliary cirrhosis
f. Chronic renal failure
6. Serum lipase levels are normal in patients with elevated amylase who have peptic ulcer, salivary adenitis,
inflammatory bowel disease, intestinal obstruction, and macroamylasemia. Coexistence of increased serum
amylase and normal lipase levels may be a helpful clue to the presence of macroamylasemia.

Clinical Alert
Panic Level for Lipase
>600 IU/L or >10 µkat/L
Interfering Factors
1. Amylase
a. Anticoagulated blood gives lower results. Do not use EDTA, citrate oxalate.
b. Lipemic serum interferes with test.
c. Increased levels are found in alcoholic patients and pregnant women and in diabetic ketoacidosis.
d. Many drugs can interfere with this test (see Appendix J).
2. Lipase
a. EDTA anticoagulant interferes with test.
b. Lipase is increased in about 50% of patients with chronic renal failure.
c. Lipase increases in patients undergoing hemodialysis.
d. Many drugs can affect outcomes. See Appendix J.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. Amylase and lipase testing are done together in the presence of abdominal
pain, epigastric tenderness, nausea, and vomiting. These findings characterize acute pancreatitis as well as other
acute surgical emergencies.
2. If amylase/creatinine clearance testing is also being done, collect a single, random urine sample at the same time
blood is drawn.
3. Follow guidelines in Chapter 1 regarding safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results and monitor as appropriate for pancreatitis or other acute abdominal conditions.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Aspartate Transaminase (Aminotransferase, AST); Serum Glutamic-Oxaloacetic Transaminase (SGOT)
Aspartate transaminase (AST) is an enzyme present in tissues of high metabolic activity; decreasing concentrations of
AST are found in the heart, liver, skeletal muscle, kidney, brain, pancreas, spleen, and lungs. The enzyme is released
into the circulation following the injury or death of cells. Any disease that causes change in these highly metabolic tissues
will result in a rise in AST levels. The amount of AST in the blood is directly related to the number of damaged cells and
the amount of time that passes between injury to the tissue and the test. Following severe cell damage, the blood AST
level will rise in 12 hours and remain elevated for about 5 days.
This test is used to evaluate liver and heart disease. The ALT is usually ordered along with the AST.
Reference Values
Normal Men: 14–20 U/L or 0.23–0.33 µkat/L Women: 10–36 U/L or 0.17–0.60 µkat/L Newborns: 47–150 U/L or 0.78–2.5
µkat/L Children: 9–80 U/L or 0.15–1.3 µkat/L Check with your laboratory. Different methods have different reference
values.
Procedure
1. Obtain a 5-mL venous sample. Serum is used. Observe standard precautions. Place specimen in a biohazard bag.
2. Avoid hemolysis.
Clinical Implications
1. Increased AST levels occur in MI.
a. In MI, the AST level may be increase to 4 to 10 times the normal values.
b. The AST level reaches a peak in 24 hours and returns to normal by post-MI day 3 to 7. Secondary rises in AST

levels suggest extension or recurrence of MI.
c. The AST curve in MI parallels that of creatinine phosphokinase (CPK).
2. Increased AST levels occur in liver diseases (10–100 times normal).
a. Acute hepatitis and chronic hepatitis (ALT > AST)
b. Active cirrhosis (drug induced; alcohol induced: AST > ALT)
c. Infectious mononucleosis
d. Hepatic necrosis and metastasis
e. Primary or metastatic carcinoma
f. Alcoholic hepatitis
g. Reye's syndrome
3. Other diseases associate with elevated AST levels include the following:
a. Hypothyroidism
b. Trauma and irradiation of skeletal muscle
c. Dermatomyositis
d. Polymyositis
e. Toxic shock syndrome
f. Cardiac catheterization
g. Recent brain trauma with brain necrosis, cerebral infarction
h. Crushing and traumatic injuries, head trauma, surgery
i. Progressive muscular dystrophy (Duchenne's)
j. Pulmonary emboli, lung infarction
k. Gangrene
l. Malignant hyperthermia, heat angiography
m. Mushroom poisoning
n. Shock
o. Hemolytic anemia, exhaustion, heat stroke
4. Decreased AST levels occur in the following conditions:
a. Azotemia
b. Chronic renal dialysis
c. Vitamin B 6 deficiency
Interfering Factors
1.
2.
3.
4.
5.

Slight decreases occur during pregnancy, when there is abnormal metabolism of pyridoxine.
Many drugs can cause elevated or decreased levels (see Appendix J). Alcohol ingestion affects results.
Exercise and IM injections do not affect results.
False decreases occur in diabetic ketoacidosis, severe liver disease, and uremia.
Gross hemolysis causes falsely high levels.

Clinical Alert
Critical Value
AST is extremely high (>20,000 U/L; >333 µkat/L) in alcohol-acetaminophen syndrome. AST > ALT, prothrombin time:
100 seconds. Creatinine: >34 mg/L or >0.30 mmol/L.m
Interventions
Pretest Patient Care
1. Explain test purpose and blood-drawing procedure. For diagnosis of MI, AST testing should be done on 3
consecutive days because the peak is reached in 24 hours and levels return to normal in 3 to 4 days.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test results and monitor appropriately for heart and liver diseases.
2. Ensure that unexplained AST elevations are further investigated with ALT and GGT tests.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Cardiac Troponin T (cTnT): Troponin I (cTnI)
Cardiac troponin is unique to the heart muscle and is highly concentrated in cardiomyocytes. These isoforms show a high
degree of cardiac specificity. This protein is released with very small areas of myocardial damage as early as 1 to 3
hours after injury, and levels return to normal within 5 to 7 days. Troponin I remains increased longer than CK-MB and is
more cardiac specific. Troponin T is more sensitive but less specific, being positive with angina at rest. These tests are
becoming the most important addition to the clinical assessment of cardiac injury.
This test is used in the early diagnosis of small myocardial infarcts that are undetectable by conventional diagnostic
methods. Cardiac troponin levels are also used later in the course of MI because they remain elevated for 5 to 7 days
after injury. A single sample may be misleading; therefore, serial sampling 0, 4, 8, and 12 hours after chest pains may be
ordered to rule out acute MI. See Table 6.11 for a list of cardiac markers.

Table 6.11 Cardiac Markers

Markers

Time of Initial Evaluation Time of Peak Evaluation Time to Return to Normal

CK-MB
4–8 h
LDH
2–5 days
Myoglobin
2–4 h
Troponin I (cTnI) 4–6 h
Troponin T (cTnT) 4–8 h

12–24 h
8–10 h
12 h
12–48 h

72–96 h
10 days
24 h
3–10 days
7–10 days

Reference Values
Normal Negative (Qualitative) Troponin I: <0.35 ng/mL or <0.35 µg/L Troponin T: <0.2 ng/mL or <0.2 µg/L Total CK:
0–120 ng/mL or 0–120 µg/L CK-MB: 0–3 ng/mL or 0–3 µg/L CK index: 0–3 LDH: 140–280 U/L or 2.34–4.68 µkat/L
Myoglobin: <55 ng/mL or <55 µg/L Troponin: <0.4 ng/mL or <0.4 µg/L Values may vary depending on the testing method
used. Check with your laboratory for reference values.
Procedure
1. Obtain a 5-mL venous blood sample in a red-topped tube within hours after onset of chest pain. Observe standard
precautions. Place specimen in a biohazard bag.
2. Be aware that serial samples may be ordered. Record date and time of sampling.
Clinical Implications
1. Positive or elevated cardiac troponin I levels indicate:
a. Small infarcts; increases remain for 5 to 7 days.
b. Myocardial injury during surgery
2. Positive or elevated cardiac troponin T
a. Acute MI
b. Perisurgical MI
c. Unstable angina
d. Myocarditis
e. Some noncardiac events
1. Chronic renal failure
2. Acute trauma involving muscle
3. Rhabdomyolysis, polymyositis, dermatomyosis
Interfering Factors
1. Cardiac troponin T levels may be increased in chronic muscle or renal disease and trauma.
2. Levels are not affected by orthopedic or lung surgery.

Clinical Alert
Critical Value
Troponin I: >1.5 ng/mL or >1.5 µg/L
Interventions
Pretest Patient Care
1. Explain that the test is a sensitive marker for minor myocardial injury in unstable angina.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test results, and counsel and monitor appropriately. Additional testing may be necessary (eg, cardiac
myosin light classes, glycogen phosphorylcholine BB [GPBB]).
2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Creatine Phosphokinase (CPK); Creatine Kinase (CK); CPK and CK Isoenzymes
Creatine kinase (CPK/CK) is an enzyme found in higher concentrations in the heart and skeletal muscles and in much
smaller concentrations in brain tissue. Because CK exists in relatively few organs, this test is used as a specific index of
injury to myocardium and muscle. CPK can be divided into three isoenzymes: MM or CK 3, BB or CK 1, and MB or CK 2.
CK-MM is the isoenzyme that constitutes almost all the circulatory enzymes in healthy persons. Skeletal muscle contains
primarily MM; cardiac muscle contains primarily MM and MB; and brain tissue, GI system, and genitourinary tract contain
primarily BB. Normal CK levels are virtually 100% MM isoenzyme. A slight increase in total CPK is reflected from
elevated BB from CNS injury. CPK isoenzyme studies help distinguish whether the CPK originated from the heart (MB) or
the skeletal muscle (MM).
The CK (CPK) test is used in the diagnosis of MI and as a reliable measure of skeletal and inflammatory muscle
diseases. CK levels can prove helpful in recognizing muscular dystrophy before clinical signs appear. CK levels may rise
significantly with CNS disorders such as Reye's syndrome. The determination of CK isoenzymes may be helpful in
making a differential diagnosis. Elevation of MB, the cardiac isoenzyme, provides a more definitive indication of
myocardial cell damage than total CK alone. MM isoenzyme is an indicator of skeletal muscle damage. Newer tests, such

as CK isoforms, allow for earlier detection of MI than is possible with CK-MB.
Reference Values
Normal Men: 38–174 U/L (0.63–2.90 µkat/L) Women: 26–140 U/L (0.46–2.38 µkat/L) Infants: 2–3 times adult values
Isoenzymes: MM (CK 3): 96%–100% MB (CK 2): 0%–6% BB (CK 1): 0%

NOTE
Normal values may vary with method of testing and reaction temperature. Check with your laboratory.

NOTE
Healthy African Americans have higher CK levels than do Caucasian and Hispanic persons.
Procedure
1.
2.
3.
4.

Obtain a 5-mL venous blood sample. Serum must be used.
Observe standard precautions. Place specimen in a biohazard bag.
If a patient has been receiving multiple IM injections, note this fact on the laboratory requisition.
Avoid hemolysis.

Clinical Implications
1. Total CK Levels
a. Increased CK/CPK levels occur in the following conditions:
1. Acute MI
a. With MI, the rise starts soon after an attack (about 4–6 hours) and reaches a peak of at least several
times normal within 24 hours. CK returns to normal in 48 to 72 hours.
b. CK and CK-MB (CK 2) peaks about 1 day after onset, as does AST.
c. Lactate dehydrogenase (LD) usually peaks 2 days after onset, when the LD 1–LD 2 inversion (flip) is
found.
d. CK-MB, LD 1, LD 1:LD 2 ratio, total CK, and total LD classically increase with acute MI. CK-MB and LD 1
increase both in percentage and absolutely (each isoenzyme percentage times the respective total
enzyme), peak, and then decrease.
e. AST testing with LD and LD isoenzymes is advocated when the patient reaches medical attention 48 to
72 hours after onset of a possible acute MI.
2. Severe myocarditis
3. After open heart surgery
4. Cardioversion (cardiac defibrillation)
5. Myocarditis
b. Other diseases and procedures that cause increased CK/CPK levels include the following:
1. Acute cerebrovascular disease
2. Progressive muscular dystrophy (levels may reach 20–200 times normal), Duchenne's muscular dystrophy,
female carriers of muscular dystrophy
3. Dermatomyositis and polymyositis
4. Delirium tremens and chronic alcoholism
5. Electric shock, electromyography
6. Malignant hyperthermia
7. Reye's syndrome
8. Convulsions, ischemia, or subarachnoid hemorrhage
9. Last weeks of pregnancy and during childbirth
10. Hypothyroidism
11. Acute psychosis
12. CNS trauma, extensive brain infarction
13. Neoplasms of prostate, bladder, or GI tract
14. Rhabdomyolysis with cocaine intoxication
15. Eosinophilia-myalgia syndrome
c. Normal values are found in myasthenia gravis and multiple sclerosis.
d. Decreased values have no diagnostic meaning and may be caused by low muscle mass and bed rest (overnight
values can drop 20%).
2. CK Isoenzymes
a. Elevated MB (CK 2 ) isoenzyme levels occur in the following conditions:
1. Myocardial infarct (rises 4–6 hours after MI; not demonstrable after 24–36 hours; ie, peak with rapid fall)
2. Myocardial ischemia, angina pectoris
3. Duchenne's muscular dystrophy
4. Subarachnoid hemorrhage
5. Reye's syndrome
6. Muscle trauma, surgery (postoperative)
7. Circulatory failure and shock
8. Infections of heart—myocarditis
9. Chronic renal failure
10. Malignant hyperthermia, hypothermia
11. CO poisoning
12. Polymyosis
13. Myoglobulinemia
14. Rocky Mountain spotted fever

b. BB (CK 1) elevations occur in the following conditions:
1. Reye's syndrome
2. Some breast, bladder, lung, uterus, testes, and prostate cancers
3. Severe shock syndrome
4. Brain injury, neurosurgery
5. Hypothermia
6. Following coronary bypass surgery
7. Newborns
c. MM (CK 1) is elevated in most conditions in which total CK is elevated.
d. MB (CK 2) is not elevated:
1. Exercise (total elevated)
2. IM injections (total elevated)
3. Strokes, cerebrovascular accident, and other brain disorders in which total CK is elevated
4. Pericarditis
5. Pneumonia, other lung diseases; pulmonary embolism
6. Seizures (CK total may be very high)

Clinical Alert
1. After an MI, MB appears in the serum in 6 to 12 hours and remains for about 18 to 32 hours. The finding of MB in
a patient with chest pain is diagnostic of MI. In addition, if there is a negative CK-MB for =48 hours following a
clearly defined episode, it is clear that the patient has not had an MI.
2. CK-MB, LD1, LD1/LD-2 ratio, total CK, and total LD classically increase with acute MI. CK-MB and LD1 increase
both in percentage and absolutely (each isoenzyme percent times the respective total enzyme), peak, then
decrease.
Interfering Factors
1. Strenuous exercise, weight lifting, and surgical procedures that damage skeletal muscle may cause increased
levels of CK.
2. Alcohol and other drugs of abuse increase CK levels.
3. Athletes have a higher CK value because of greater muscle mass.
4. Multiple IM injections may cause increased or decreased CK levels (see Appendix J).
5. Many drugs may cause increased CK levels.
6. Childbirth may cause increased CK levels.
7. Hemolysis of blood sample causes increased CK levels.
Interventions
Pretest Patient Care
1.
2.
3.
4.

Explain test purpose and need for at least three consecutive blood draws following episode.
Note on requisition when suspected cardiac episode occurred, and dates and times of blood draws.
Do not allow exercise before test.
Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results and monitor as appropriate for MI, muscular dystrophy, and other causes of abnormal test
outcomes.
3. Remember that high levels of CK/CK-MB may suggest other tests should be done to support diagnosis of acute MI:
a. Total leukocyte count and differential
b. Cardiac troponin T
c. Myoglobin
4. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Galactose-1-Phosphate Uridyltransferase (GPT); Galactokinase; Galactose-1-Phosphate
The enzyme galactose-1-phosphate uridyltransferase is needed in the use of galactose-1-phosphate so that is does not
accumulate in the body. A very rare genetic disorder resulting from an inborn (inherited or acquired during intrauterine
development) error of galactose metabolism may occur.
This measurement is used to identify galactose defects, which can result in widespread tissue damage and abnormalities
such as cataracts, liver disease, and renal disease. It also causes failure to thrive and mental retardation. The screening
test should be done immediately to enable diet treatment if test is positive.
Reference Values
Normal Galactose-1-phosphate uridyltransferase: 18.5–28.5 U/g of hemoglobin (Hb) or 1.19–1.84 mU/mol Hb
Galactose-1-phosphate (dried blood spot-screening): <0.74 mmol/L Galactokinase Children 0–2 years: 11–150 mU/g Hb
or 183–2500 pkat/g Hb Children 2–18 years: 11–54 mU/g Hb or 183–900 pkat/g Hb Adults: 12–40 mU/g Hb or 200–667
pkat/g Hb
Procedure
1. Obtain a 5-mL venous blood sample.
2. Anticoagulate with heparin.

3. Observe standard precautions. Place specimen in a biohazard bag.
Clinical Implications Decreased values are associated with galactosemia, a rare genetic disorder transmitted in an
autosomal recessive fashion. The resulting accumulation of galactitol and/or galactose-1-phosphate can result in juvenile
cataracts, liver failure, failure to thrive, and mental retardation in persons with galactose-1-phosphate uridyltransferase
deficiency.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. Genetic counseling may be necessary.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test results and counsel appropriately. See newborn screening in Chapter 11.
2. Instruct parents of infants and children with positive test results that the disease can effectively treated by removing
galactose-containing foods, especially milk, from the diet. With dietary galactose restriction, liver and lens changes
are reversible.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Hexosaminidase, Total and Isoenzyme A
Three isoenzymes of hexosaminidase have been identified in serum: A (acid form), B (base form), and S.
Hexosaminidase A is a lysosomal isoenzyme, deficiency of which characterizes patients with Tay-Sachs disease.
Homozygotes have no hexosaminidase A and a large increase in hexosaminidase B and S. Heterozygotes have a
moderate decrease in hexosaminidase A and a slight increase of hexosaminidase B and S.
Hexosaminidase A is used as a diagnostic test for Tay-Sachs disease and can be of help in identifying carriers among
persons with no family history of Tay-Sachs. This condition is due to an autosomal recessive trait found predominantly,
but not exclusively, in Ashkenazi Jews and is characterized by the appearance during infancy of psychomotor
deterioration, blindness, cherry-red spot on the macula, and an exaggerated extension response to sound. In the brains
of affected children, the level of ganglioside is increased 100 times owing to the deficiency of this enzyme.
Reference Values
Normal Percentage of normal total hexosaminidase A 56%–80% noncarrier: 7.2–9.88 U/L or 120–165 nkat/L <50%
heterozygous: 3.30–5.39 U/L or 55–90 nkat/L 0% Tay-Sachs: 0 U/L Total hexosaminidase Noncarrier: 9.83–15.95 U/L or
164–266 nkat/L Heterozygous: 3.30–5.39 U/L or 55–90 nkat/L (carrier) Homozygous Tay-Sachs: 17.1 U/L or 285 nkat/L
Leukocyte hexosaminidase total: 16.4–36.2 U/g cellular protein or 273–603 nkat/g cellular protein Leukocyte
hexosaminidase A: 63%–75% of total (normal) Normal values vary with method of testing used. Check with your
laboratory for reference values.
Procedure
1. Obtain a 5-mL venous blood sample. Allow blood to clot at +3°C and centrifuge at 3°C. The test uses serum. If the
test is not performed immediately, serum must be frozen.
2. Be aware that if leukocyte hexosaminidase A is ordered also, a heparinized sample is needed. Place in ice
immediately. Place specimens in biohazard bags.
Clinical Implications
1. Decreased hexosaminidase A. An almost total deficiency of the A component is diagnostic of Tay-Sachs disease or
GM2 gangliosidosis. The total hexosaminidase is of no value in Tay-Sachs.
2. Decreased hexosaminidase A and B. In a variant of Tay-Sachs disease known as Sandhoff's disease, both A and B
isoenzymes are defective, causing an absence of this enzyme. The total hexosaminidase level is also decreased in
Sandhoff's disease.
3. Increased total hexosaminidase occurs in the following conditions:
a. Hepatic disease (biliary obstruction)
b. Gastric cancer
c. Myeloma
d. MI
e. Vascular complications of diabetes mellitus

Clinical Alert
Pregnancy results in increased serum levels of total hexosaminidase and decreased hexosaminidase A, which gives a
false appearance of being a carrier. Therefore, during pregnancy, the serum test should never be done. However, the
leukocyte test is valid in pregnancy and should be used.
Interfering Factors
1. Total values are increased in pregnancy (5 times normal).
2. Oral contraceptives falsely increase values.

Clinical Alert
Critical Values for Hexosaminidase A
Less than 50% of total activity indicates Tay-Sachs carrier. If the serum Hex A test levels are ambiguous the leukocyte
test should be done.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. Genetic counseling may occur before testing.
2. Be aware that pregnancy and/or oral contraceptives are contraindications for testing.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test results and be prepared to perform genetic counseling of patient and family. The physician should be
informed as soon as possible.
2. Follow guidelines in Chapter 1 for safe, effective, informed, posttest care .
Lactate Dehydrogenase (LD, LDH)
Lactate dehydrogenase is an intracellular enzyme that is widely distributed in the tissues of the body, particularly in the
kidney, heart, skeletal muscle, brain, liver, and lungs. Increases in the reported value usually indicate cellular death and
leakage of the enzyme from the cell.
Although elevated levels of LDH are nonspecific, this test is useful in confirming myocardial or pulmonary infarction when
viewed in relation to other test findings. For example, LD remains elevated longer than CK in MI. LDK level is also helpful
in the differential diagnosis of muscular dystrophy and pernicious anemia. More specific findings may be found by
breaking down the LDH into its five isoenzymes. (When LD values are reported or quoted, total LDH is meant.)
Reference Values
Normal Newborn: 160–450 U/L Children: 60–170 U/L Adults: 140–280 U/L Normal values vary with method of testing
used. Check with your laboratory for reference values.
Procedure
1. Obtain a 5-mL venous blood sample. Serum is used. Observe standard precautions.
2. Avoid hemolysis in obtaining blood sample. Place specimen in a biohazard bag.
Clinical Implications
1. Increased LDH (LD) occurs in the following conditions:
a. High levels occur within 36 to 55 hours after MI and continue longer than elevations of SGOT or CPK (3–10
days). Differential diagnosis of acute MI may be accomplished with LDH isoenzymes.
b. In pulmonary infarction, increased LDH occurs within 24 hours of pain onset. The pattern of normal SGOT and
elevated LDH that levels off 1 to 2 days after an episode of chest pain is indicative of pulmonary infarction.
c. Elevated levels of LDH are also observed in various other conditions:
1. Congestive heart failure
2. Liver diseases (eg, cirrhosis, alcoholism, acute viral hepatitis)
3. Malignant neoplasms, cancer, leukemias, lymphoma
4. Hypothyroidism
5. Lung diseases
6. Skeletal muscle diseases (muscular dystrophy), muscular damage
7. Megaloblastic and pernicious anemias, hemolytic anemia, sickle cell disease
8. Delirium tremens, seizures
9. Shock, hypoxia, hypotension
10. Hyperthermia
11. Renal infarct
12. CNS diseases
13. Acute pancreatitis
14. Fractures, other trauma including head
15. Intestinal obstruction
d. Angina and pericarditis do not produce LDH elevations.
2. Decreased LDH levels are associated with a good response to cancer therapy.
Interfering Factors
1. Strenuous exercise and the muscular exertion involved in childbirth cause increased LDH levels.
2. Skin diseases can cause falsely increased LDH levels.
3. Hemolysis of red blood cells due to freezing, heating, or shaking the blood sample will cause falsely increased LDH
levels.
4. Various drugs may cause increased or decreased LDH levels (see Appendix J).

Clinical Alert
LDH is found in nearly every tissue of the body; therefore, elevated levels are of limited diagnostic value by
themselves. Differential diagnoses may be accomplished with LD isoenzyme determination.
Interventions
Pretest Patient Care
1. Explain test purpose and blood-drawing procedure. Obtain recent history of MI or pulmonary infarction.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Resume normal activities.
2. Interpret test results and monitor for myocardial and pulmonary infarction and other diseases related to abnormal
results. LD isoenzymes may be ordered.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Lactate Dehydrogenase (LDH, LD) Isoenzymes (Electrophoresis)
Electrophoresis, or separation, of LDH identifies the five isoenzymes of fractions of LDH, each with its own physical
characteristics and electrophoretic properties. Fractioning the LDH activity sharpens its diagnostic value because LDH is
found in many organs. LD isoenzymes are released into the bloodstream when tissue necrosis occurs. The isoenzymes
are elevated in the terms of patterns established, not on the basis of the value of a single isoenzyme. The origins of the
LDH isoenzymes are as follow: LD 1 and LD 2 are present in cardiac tissue and erythrocytes; LD 3 originates mainly from
lung, spleen, pancreas, and placenta; and LD 4 and LD 5 originate from skeletal muscle and liver.
The five isoenzyme fractions of LDH show different patterns in various disorders. Abnormalities in the pattern suggest
which tissues have been damaged. This test is useful in the differential diagnosis of acute MI, megaloblastic anemia (eg,
folate deficiency, pernicious anemia), hemolytic anemia, and very occasionally, renal infarct. These entities are
characterized by LD 1 increases, often with LD 1 :LD 2 inversion (flip).
Reference Values
Normal LDH 1 : 17%–27% of total or 0.17–0.27 LDH 2: 29%–39% of total or 0.29–0.39 LDH 3: 19%–27% of total or
0.19–0.27 LDH 4 : 8%–16% of total or 0.08–0.16 LDH 5: 6%–16% of total or 0.06–0.16
Procedure
1. Obtain a 5-mL venous blood sample. Serum is needed.
2. Avoid hemolysis.
3. Observe standard precautions. Place specimen in a biohazard bag. Be aware that serial determinations may be
ordered (3 consecutive days).
Clinical Implications
1. Abnormal LD 1 and LD 2 patterns reflect damaged tissues (see Table 6.12).
Table 6.12 Abnormal LD Isoenzyme Patterns
Disease

LD 1

LD 2

Myocardial infarction
Pulmonary infarction
Congestive heart failure
Viral hepatitis
Toxic hepatitis
Leukemia, granulocytic
Pancreatitis
Carcinomatosis (extensive)
Megaloblastic anemia
Hemolytic anemia
Muscular dystrophy

X

X

X
X
X

X
X
X
X
X
X

LD 3

LD 4

LD 5

X
X
X
X

X
X
X
X

X
X
X

a. The appearance of an LD flip (ie, when LD 1 level is higher than LD 2 level) is extremely helpful in the diagnosis
of MI. The presence of an LD flip 1 day following incident or with the detection of CK-MB is essentially
diagnostic of MI if baseline cardiac enzymes/ isoenzymes are normal and if rises and falls are as anticipated for
the diagnosis of acute MI.
b. Persistent LD 1–LD 2 flip following acute MI may represent reinfarction. When acute MI is complicated by shock,
a normal pattern may be found. LD 1–LD 2 inversion commonly appears subsequent to the isomorphic pattern in
instances of acute MI.
c. The LDH pattern in hemolytic, megaloblastic, and sickle cell anemia is essentially the same as in MI and other
anemias. This is because red blood cells have an isoenzyme pattern similar to that of heart muscle. The time
elapsed to peak values may help to differentiate these conditions.

2. LD 3 increases occur in advanced cancer and malignant lymphoma; this level should decrease following effective
therapy. LD 3 is occasionally elevated in pulmonary infarction or pneumonia.
3. LD 5 is increased in the following conditions:
a. Liver disease, hepatitis
b. Congestive heart failure, pulmonary edema
c. Striated muscle trauma, burns
4. LD 5 increase is more significant when LD 5 /LD 4 ratio is increased.
5. In most cancers, one to three of the bands (LD 2 , LD 3 and LD 4) are frequently increased. A notable exception is in
seminomas and dysgerminomas, in which LD 1 is increased. Frequently, an increase in LD 3 may be the first
indication of the presence of cancer.
6. All LD isoenzymes are increased in systemic diseases (eg, carcinomatous collagen vascular, disseminated
intravascular coagulation, sepsis) (see Table 6.12).
7. Increased total LD with normal distribution of isoenzymes may be seen in coronary artery disease (CAD) with
chronic heart failure, hypothyroidism, infectious mononucleosis and other inflammatory states, uremia, and
necrosis.

Clinical Alert
1. LD isoenzyme testing should be reserved for diagnosis of complex cases. In 5% to 20% of patients with acute MI,
the expected reversal of LD-1/LD-2 does not occur; in these patients, there is often simply an increase in LD-1.
2. LDH isoenzymes should be interpreted in light of clinical findings.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. Repeat testing on 3 consecutive days is likely. Obtain pertinent clinical signs
and symptoms.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Have patient resume normal activities.
2. Interpret test results and monitor appropriately for abnormal LD patterns, MI, and pulmonary infarctions.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Renin (Angiotensin); Plasma Renin Angiotensin (PRA)
Renin is an enzyme that converts angiotensinogen to angiotensin I. Derived from the liver, angiotensinogen is an a
2 -globulin in the serum. Angiotensin I is then converted in the lung to angiotensin II. Angiotensin II is a potent
vasopressor agent responsible for hypertension of renal origin and is a powerful releaser of aldosterone from the adrenal
cortex. Both angiotensin II and aldosterone increase blood pressure. Renin levels increase when there is decreased
renal perfusion pressure. The renin-aldosterone axis regulates sodium and potassium balance and blood volume and
pressure. Renal reabsorption of sodium affects plasma volume. Low plasma volume, low blood pressure, low sodium,
and increased potassium induce renin release, causing increased aldosterone through stimulation of angiotensin.
Potassium loss, acute blood pressure increases, and increased blood volumes suppress renin release.
This test is most useful in the differential diagnosis of hypertension, whether essential, renal, or renovascular. In primary
hyperaldosteronism, the findings will demonstrate that aldosterone secretion is exaggerated and secretion of renin is
suppressed. In renal vascular disease, renin is elevated.
Reference Values
Normal Renin activity—plasma (PRA) Adult (normal-sodium diet): Supine: 0.2–1.6 ng angiotensin I (AI)/mL/h or 0.2–1.6
µg AI/h/L Standing: 0.7–3.3 ng AI/mL/h or 0.7–3.3 µg AI/h/L Adult (low-sodium diet): Supine: renin levels increase 2 times
normal. Standing: renin levels increase 6 times normal. Renin direct: Adult supine: 12–79 mU/L Adult standing: 13–114
mU/L
Procedure
1. Obtain a 5-mL venous blood sample. Fasting is required. Collect specimen with scrupulous attention to detail. Use
EDTA as the anticoagulant to aid in preservation of any angiotensin formed before examination. Observe standard
precautions.
2. Draw blood in chilled tubes and place samples on ice. Transport samples to laboratory immediately in a biohazard
bag. Must be centrifuged in refrigerated centrifuge.
3. Record posture and dietary status of patient at time of blood drawing.
4. A 24-hour urine sodium should be done concurrently to aid in diagnosis.
Clinical Implications
1. Increased renin levels occur in the following conditions:
a. Secondary aldosteronism with malignant hypertension
b. Renovascular hypertension
c. Reduced plasma volume due to low-sodium diet, diuretics, Addison's disease, or hemorrhage.
d. Chronic renal failure
e. Salt-losing status owing to GI disease (Na and K wastage)
f. Renin-producing tumors of kidney

g. Few patients (15%) with essential hypertension
h. Bartter's syndrome (high in renin hypertension)
i. Pheochromocytoma
2. Decreased renin levels are found in the following conditions:
a. Primary aldosteronism (98% of cases)
b. Unilateral renal artery stenosis
c. Administration of salt-retaining steroids
d. Congenital adrenal hyperplasia with 17-hydroxylase deficiency
e. Liddle's syndrome
Interfering Factors
1. Levels vary in healthy persons and increase under influences that tent to shrink the intravascular fluid volume.
2. Random specimens may be difficult to interpret unless dietary and salt intake of patient is regulated.
3. Values are higher when the patient is in an upright position, when the test is performed early in the day, when the
patient is on a low-sodium diet, during pregnancy, and with drugs such as diuretics and antihypertensives and
foods such as licorice. See Appendix J for other drugs that affect outcomes.
4. Recently administered radioisotopes interfere with test results.
5. Indomethacin and salicylates decrease renin levels.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure.
2. Remember that a regular diet that contains 180 mEq (180 mmol/L) of sodium and 100 mEq (100 mmol/L) of
potassium must be maintained for 3 days before the specimen is obtained. A 24-hour urine sodium and potassium
should also be done to evaluate salt balance. The blood test should be drawn at the end of the 24 hour urine test.
3. Instruct the patient that it is necessary to be in a supine position for at least 2 hours before obtaining the specimen.
The specimen is drawn with patient in the supine position.
4. Ensure that antihypertensive drugs, cyclic progestogens, estrogens, diuretics, and licorice are terminated at least 2
weeks and preferably 4 weeks before a renin-aldosterone workup.
5. Remember that if a standing specimen is ordered, the patient must be standing for 2 hours before testing, and
blood should be drawn with the patient in the sitting position.
6. Do not allow caffeine ingestion the morning before or during the test.
7. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test results and counsel appropriately regarding hypertension, further testing and possible treatment.
2. Have patient resume normal activities.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Renin Stimulation/Challenge Test
Challenge Test A challenge test distinguishes primary from secondary hyperaldosteronism on the basis of renin levels.
The test is performed with the patient in both the recumbent and upright positions and after the patient has been
maintained on a low-salt diet. In normal persons and in those with essential hypertension, renin concentration is
increased by the reduction in volume due to sodium restriction and the upright position. In primary aldosteronism, volume
depletion does not occur, and renin concentration remains low.
Reference Values
Normal See challenge test above.
Procedure
1. Admit the patient to the hospital for this test. On admission, obtain and record the patient's weight.
2. Ensure the patient follows a reduced-sodium diet supplemented with potassium for 3 days, along with diuretics (eg,
furosemide, chlorothiazide), as ordered.
3. Weigh patient again on the third day, record data, and ensure that the patient remains upright for 4 hours and
participates in normal activities.
4. Obtain a venous heparinized blood sample for renin at 11:00 a.m., when renin is usually at its maximum level.
Place specimen on ice, and send it immediately to the laboratory in a biohazard bag.
Interpretation of Renin Stimulation Test
In healthy persons and most hypertensive patients, the stimulation of a low-salt diet, a diuretic, and upright posture will
raise renin activity to very high levels and result in weight loss. However, in primary aldosteronism, the plasma level is
expanded and remains so. In these patients, there is little if any weight loss, and the renin level is very low or
undetectable. A response within the normal range can occur in the presence of aldosterone.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. The purpose of the preparation is to deplete the patient of sodium.
2. Check with individual laboratory for specific practices.
3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Aftercare
1. Resume normal activities.
2. Interpret test results and counsel appropriately regarding hypertension.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
?-Glutamyltransferase (?-Glutamyl Transpeptidase, GGT, ?GT)
The enzyme ?-glutamyl transpeptidase is present mainly in the liver, kidney, and pancreas. Despite the fact that the
kidney has the highest level of this enzyme, the liver is considered the source of normal serum activity. ?GT has no origin
in bone or placenta.
This test is used to determine liver cell dysfunction and to detect alcohol-induced liver disease. Because the GGT is very
sensitive to the amount of alcohol consumed by chronic drinkers, it can be used to monitor the cessation or reduction of
alcohol consumption in chronic alcoholic patients and early-risk drinkers. GT activity is elevated in all forms of liver
disease. This test is much more sensitive than either the alkaline phosphatase test or the transaminase test (ie, SGOT,
SGPT) in detecting obstructive jaundice, cholangitis, and cholecystitis. It is also indicated in the differential diagnosis of
liver disease in children and pregnant women who have elevated levels of LDH and alkaline phosphatase. ?GT is also
useful as a marker for prostatic cancer and hepatic metastasis from breast and colon.
Reference Values
Normal Men: 7–47 U/L (0.12–1.80 µkat/L) Women: 5–25 U/L (0.08–0.42 µkat/L) Values higher in newborns and in the
first 3–6 months. Values in adult males are 25% higher than in females. Values vary with method (check with your
laboratory).
Procedure
1. Obtain a 5-mL venous blood sample. Serum is used.
2. Observe standard precautions. Place specimen in a biohazard bag.
Clinical Implications
1. Increased ?GT levels are associated with the following conditions:
a. Liver diseases
1. Hepatitis (acute and chronic)
2. Cirrhosis (obstructive and familial)
3. Liver metastasis and carcinoma
4. Cholestasis (especially during or following pregnancy)
5. Chronic alcoholic liver disease, alcoholism
6. Infectious mononucleosis
b. ?GT levels are also increased in the following conditions:
1. Pancreatitis
2. Carcinoma of prostate
3. Carcinoma of breast and lung
4. Systemic lupus erythematosus
5. Glycogen storage disease
c. In MI, ?GT is usually normal. However, if there is an increase, it occurs about 4 days after MI and probably
implies liver damage secondary to cardiac insufficiency.
d. Hyperthyroidism
2. Decreased ?GT levels are found in hypothyroidism.
3. ?GT values are normal in bone disorders, bone growth, pregnancy, skeletal muscle disease, strenuous exercise,
and renal failure. Children and adolescents are normal.
Interfering Factors
1. Various drugs, (eg, phenothiazines and barbiturates) affect test outcomes (see Appendix J).
2. Alcohol (ethanol)
Interventions
Pretest Patient Care
1. Explain test purpose and blood-drawing procedure. No alcohol is allowed before the test.
2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Resume normal activities.
2. Interpret test results and monitor as appropriate for liver, pancreatic, or thyroid disease and/or cancer recurrence.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Homocysteine (tHcy)
Homocysteine (tHcy) is an amino acid resulting from the synthesis of cysteine from methionine and enzyme reaction of
cobalamin and folate. Large quantities of homocysteine are excreted and assimilated in the blood plasma of patients with

homocystinemia associated with:
1.
2.
3.
4.

Increased risk for vascular disease
Increased risk for venous thrombosis
Elevated homocysteine with a direct toxic effect on endothelium
Elevated in folic acid deficiency and B 12 deficiency. Folic acid deficiency is characterized by elevated plasma
homocysteine; folic acid supplementation reduces plasma homocysteine. Elevated plasma homocysteine levels due
to aberrant vitamin B 12 respond favorably to vitamin B 12 supplementation.
5. Increased risk for pregnancy complications and neural tube defects
This test measures the blood plasma level of homocysteine. It is useful for diagnosing individuals with potential increased
risk factors for coronary artery disease and thromboses, for providing a functional assay for folic acid deficiency, and for
diagnosing homocystinemia. Homocysteine is retained by persons with reduced renal function. See Chart 6.3 for testing
guidelines.

Chart 6.3 Homocysteine Testing
Reasons to Test for Homocysteine
Unexplained anemia
Peripheral neuropathy or myelopathy
Recurrent spontaneous abortions or infertility
Delayed development or failure to thrive in infants
Who to Test
Elderly people (>75 years of age)
Vegetarians who are not taking vitamin B 12 supplement
Patients using drugs that interfere with folate status (eg, antiepileptics, methotrexate)
How Often to Test
Measured every 3–5 years
In newborns at 3–5 days
tHcy in Coronary Vascular Disease
In patients <40 years of age who have CVD to exclude homocystinuria
In patients who are at high risk for CVD every 3–5 years
Footnote
Source: Clinical Laboratory News, 2002

Reference Values
Normal 4–17 µmol/L or 0.54–2.30 mg/L for fasting specimens
Procedure
1. Obtain a venous blood sample. Serum or heparinized plasma is needed. Fasting is necessary.
2. Observe standard precautions. Place specimen in a biohazard bag.
3. Place on ice immediately after drawing. Centrifuge immediately and freeze within 1 hour of collection.
Clinical Implications Increased or elevated homocysteine levels occur in the following conditions:
1. Folic acid deficiency
2. Abnormal vitamin B 12 metabolism and deficiency
3. Homocystinuria

Clinical Alert
Homocysteine values and their relation to CAD are still being investigated. The methionine load test is also currently
investigative and has not yet been approved as a routine test.
Interfering Factors

1. Penicillamine reduces plasma levels of homocysteine.
2. Nitrous oxide, methotrexate deficiency, and azauridine increase plasma levels of homocysteine.
Interventions
Pretest Patient Care
1.
2.
3.
4.

Explain test purpose and blood-drawing procedure.
Remember that the test requires fasting.
Evaluate renal function in patients with homocystinuria.
Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Aftercare
1. Allow the patient to eat and drink after blood is drawn.
2. Interpret test results and counsel appropriately.
3. Evaluate for other cardiovascular risk factors, compare test results, and monitor appropriately. Promote lifestyle
changes accordingly.
4. Monitor for folic acid or vitamin B 12 deficiency and provide supplements as needed.
5. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
a 1-Antitrypsin (AAT)
a 1-Antitrypsin is a protein produced by the liver that inhibits the protease released into body fluids by dying cells. This
protein deficiency is associated with pulmonary emphysema and liver disease, both at an early age. Human serum
contains at least three inhibitors of protease. Two of the best known are a 1 -antitrypsin and a 2 -macroglobulin. Total
antitrypsin levels in blood are composed of about 90% AAT and 10% a 2-macroglobulins.
This is a nonspecific method to diagnose inflammation, severe infection, and necrosis. AAT measurement is important for
diagnosing respiratory disease and cirrhosis of the liver because of its direct relation to pulmonary and other metabolic
disorders. Pulmonary problems such as emphysema occur when antitrypsin-deficient persons are unable to ward off the
action of endoproteases. Those who are deficient in AAT develop emphysema at a much earlier age than do other
emphysema patients.
Reference Values Normal (by rate nephelometry) 110–200 mg/dL or 1.1–2.0 g/L If result is <125 mg/dL (<1.25 g/L),
phenotype should be determined to confirm homozygous and heterozygous deficiencies.
Procedure
1. Obtain a 7-mL serum sample. Use a red-topped tube.
2. Observe standard precautions. Place specimen in a biohazard bag.
Clinical Implications
1. Interpretation of AAT levels is based on the following:
a. High levels are generally found in normal persons.
b. Intermediate levels are found in persons with a predisposition to pulmonary emphysema.
c. Low levels are found in persons with obstructive pulmonary disease and in children with cirrhosis of the liver.
2. Increased AAT levels occur in the following conditions:
a. Acute and chronic inflammatory disorders
b. After injections of typhoid vaccine
c. Cancer
d. Thyroid infections
e. Oral contraceptive use
f. Stress syndrome
g. Hematologic abnormalities
3. Decreased AAT levels are associated with these progressive diseases:
a. Adult, early-onset, chronic pulmonary emphysema
b. Liver cirrhosis in infants (neonatal hepatitis)
c. Pulmonary disease
d. Severe hepatic damage
e. Nephrotic syndrome
f. Malnutrition

Clinical Alert
Patients with serum levels <70 mg/dL (<0.70 g/L) are likely to have a homozygous deficiency and are at risk for early
lung disease.
Interfering Factors a 1-Antitrypsin in an acute-phase reactant, and any inflammatory process will elevate serum levels.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. Fasting is required if the patient's history shows elevated cholesterol and/or
triglyceride levels.

2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test results and counsel appropriately. Advise patients with decreased levels to avoid smoking and, if
possible, occupational hazards such as dust, fumes, and other respiratory pollutants.
2. Be aware that because AAT deficiencies are inherited, genetic counseling may be indicated. Follow-up AAT
phenotype testing can be performed on family members to determine the homozygous or heterozygous nature of
the deficiency.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

DRUG MONITORING
Drug monitoring is used for therapeutic management and toxicology. Blood, urine, and gastric contents are the most
common specimens used for measuring drug levels. When a combination of drugs has been used, the levels of all drugs
should be obtained. Toxic drug levels are necessary to evaluate substance abuse and intentional or accidental overdose
so immediate interventions can be initiated (eg, enhanced diuresis, hemodialysis, adding soybean oil to bathwater) to
avoid death or disabling conditions. Situations in which toxic drug levels may be measured include accidental overdose
of opiates; suspected poisoning as in homicide or suicide; medical emergencies where person arrives at ED in coma or
altered state of consciousness; suspected date rape situations where a drug may have been used; accidental poisoning
in children; child abuse cases where results may be used to determine parental custody; illicit drug use such as heroine,
cocaine, or opiates; suspected solvent vapor abuse such as sniffing of paints; exposure to anticoagulants as in rodent
poisons; exposure to iron and heavy metals; intentional ingestion as in chronic overdose secondary to chronic pain; and
in vehicle accident cases where alcohol is the most commonly abused. See Appendix L for discussion of these drug
investigation studies.
Therapeutic Drug Management
Therapeutic drug management (formerly called therapeutic drug monitoring) is a reliable and practical approach to
improving drug therapy in both instruction and maintenance in individual patients. Determination of drug levels is
especially important when the potential for drug toxicity is significant or when an inadequate or undesirable response
follows the use of a standard dose. Therapeutic drug management provides an easier and more rapid estimation of
appropriate drug-dosage requirements than does observation of the drug effects themselves. For some drugs, monitoring
is routinely useful (eg, digoxin); for others, it can be helpful in certain situations (eg, antibiotics). The plasma level of
drugs needed to control the patient's symptoms is called the therapeutic concentration; at a steady state, the rate of drug
administration is equal to the rate of drug elimination, and the concentration of the drug remains constant. Monitoring at
intervals minimizes the possibility of the development of dose-related side effects. If single-drug therapy is not effective,
therapeutic monitoring allows the clinician to select supplementary medication and monitor its effect on the primary drug.
It should be noted that for many medications, therapeutic serum levels have not been established. Therapy is guided by
clinical response and adverse reactions of the medications. Appropriate therapy may be monitored or managed by other
methods, including outcome of liver function tests, CBC with differential, platelet counts, serum electrolytes, serum
albumin, and renal function tests.
Indications for Testing
1. Verify correct drug dosage and level; drug source, dose, or regimen is changed
2. When noncompliance (nonadherence) is suspected, and patient motivation to maintain medication is poor
Reference Values
Normal See Table 6.13 for therapeutic maintenance and toxic levels.
Table 6.13 Blood Concentrations of Commonly Monitored Drugs
Name of Drug

Therapeutic Level

Toxic Level

Acetaminophen

10–20 µg/mL, based on relief of symptoms

Amikacin

Infections: 20–30 µg/mL (34–52 µmol/L)
Serious infections: 20–25 µg/mL
UTI: 15–20 µg/mL
Trough
Serious infection: 1–4 µg/mL (2–7 µmol/L)
Life-threatening infections: 4–8 µg/mL (7–14
µmol/L)
0.5–2.5 mg/L (0.8–3.9 µmol/L)

Should be >200 µg/mL at 4 hours after ingestion
or
>50 µg/mL at 12 hours after ingestion
Peak: >35 µg/mL (>60 µmol/L)
Trough: >10 µg/mL (>17 µmol/L)

Amiodarone (see Fig.
6.4)
Chloramphenicol

Desipramine

Meningitis: Peak: 15–25 µg/mL
Trough: 5–15 µg/mL
Other infections: Peak: 10–20 µg/mL
Trough: 5–10 µg/mL
50–300 ng/mL

Digoxin

CHF: 0.8–2 ng/mL (1.0–2.6 nmol/L)

>3.5 mg/L
>40 µg/mL

Possibly toxic: >300 ng/mL
Toxic: >1000 ng/mL
>2.0 ng/mL (>2.6 nmol/L)

Arrhythmias: 1.5–2.5 ng/mL (2.0–3.2 nmol/L)
Adverse reactions: nausea, vomiting,
anorexia,
green/yellow visual distortion (commonly
reported
symptoms in patients requiring hospitalization)
Digitoxin (see Fig. 6.5) 18–35 ng/mL (24–46 nmol/L)
Disopyramide (Norpace) Atrial arrhythmias: 2.8–3.2 µg/mL (8.3–9.4
µmol/L)
Ventricular: 3.3–7.5 µg/mL (>9.7–22.2 µmol/L)
Epinephrine *
31–95 pg/mL
Ethasuximide (Zarontin) 40–100 µg/mL (284–710 µmol/L)
Ethchlorvynol
2–9 µg/mL or 14–55 µmol/L
Flecainide
0.2–1 µg/mL
Flucytosine (Ancobon) 25–100 µg/mL
Fluoxetine
100–800 ng/mL (289–2312 nmol/L)
Norfluoxetine 100–600 ng/mL (289–1735
nmol/L
Flurazepam *
0–4 ng/mL (0–9 nmol/L)
Fosphenytoin
10–20 µg/mL
Gabapentin *
Minimum effective serum level: 2 µg/mL
Gentamicin (Garamycin) Peak:

Ibuprofen
Lidocaine

Lithium

Lorazepam
Methotrexate

>35 ng/mL (>46 nmol/L)
>7 µg/mL (>2.1 µmol/L)

A toxic level has not been established
Panic value: >150 µg/mL (>1062 µmol/L)
A toxic level has not been established
>1.0 µg/mL
100–120 µg/mL
Fluoxetine + norfluoxetine
>2000 ng/mL (>5780 nmol/L)
>200 ng/mL (>578 nmol/L)
30–50 µg/mL
Lethal: >100 µg/mL
>25 µg/mL
Toxic level is based on panic or life-threatening
values.

Serious infections: 6–8 µg/mL (12–17 µmol/L)
Life-threatening: 8–10 µg/mL (17–21 µmol/L)
UTI: 4–6 µg/mL (8–12 µmol/L)
Trough
Serious infections:
0.5–1 µg/mL (1–2 µmol/L)
Life-threatening:
1–2 µg/mL (2–4 µmol/L)
20–70 µg/mL, based on symptom relief
>500 µg/mL
1.5–5.0 µg/mL (6.14–21.4 µmol/L)
Potentially toxic: >6 µg/mL (>25 µmol/L)
Toxic: >8.0 µg/mL (>34 µmol/L). Seizures at this
level,
fatal at >15 µg/mL (>64.5 µmol/L)
Acute mania: 0.6–1.2 mEq/L (0.6–1.2 mmol/L) >2 mEq/L (>2 mmol/L)
Protection against future episodes in patients Adverse effect levels:
with
bipolar disorder:
GI complaints/tremor: 1.5–2 mEq/L (1.5–2.0
mmol/L)
0.8–1 mEq/L (0.8–1.0 mmol/L)
Contusion/somnolence: 2–2.5 mEq/L (2.0–2.5
mmol/L)
Depression: 0.5–1.5 mmol/L
Seizure/death: >2.5 mEq/L (>2.5 mmol/L)
50–240 ng/mL
Toxic levels not established
Depends on low or high dose therapy
Low dose toxic therapy: >9.1 ng/mL
High dose toxic therapy: >450+ ng/mL
0.5 µg/mL
Potentially toxic: >9.1 ng/mL (>20 mmol/L)
Active metabolite (10-hydrox-carbazepine)
>2 µg/mL (>9 µmol/L)

Mexiletine
Oxcarbazepine *
(Trileptal)
For trigeminal neuralgia 50–110 µmol/L; therapeutic serum levels have
not
been established for treatment of epilepsy.
Procainamide
4–10 µg/mL (17–42 µmol/L)
NAPA: 10–30 µg/mL (42–127 µmol/L)
Combined: >30 µg/mL (>127 µmol/L)
Phenytoin
Children and adults:
Total phenytoin: 10–20 µg/mL (40–70 µmol/L)
Neonates
8–15 µg/mL
Free phenytoin: 1–2.0 µg/mL (4–8 µmol/L)
Salicylates
Antiplatelet, antipyresis, analgesia: 100 µg/mL
Anti-inflammatory: 150–300 µg/mL
Temazepam
26 ng/mL after 24 hours
Theophylline
Asthma: 10–20 µg/mL (56–111 µmol/L)
Neonatal apnea: 6–13 µg/mL (33–72 µmol/L)
Pregnancy: 3–12 µg/mL (17–67 µmol/L)

Toxic levels not established

>14 µg/mL (>60 µmol/L)
Combined: >30 µg/mL (>127 µmol/L)
25–50 µg/mL (120–200 µmol/L)
Lethal: >100 µg/mL (>400 µmol/L)

Information not available
>20 µg/mL (>111 µmol/L)
>10 µg/mL (>56 µmol/L)
>30 µg/mL (>168 µmol/L)

Thiopental

Hypnotic: 1–5 µg/mL
Anesthesia: 7–130 µg/mL
Valproic acid
50–120 µg/mL (wide therapeutic range)
Vancomycin
Peak: 25–40 µg/mL (17–27 µmol/L)
Trough: 5–10 µg/mL (3.4–6.8 µmol/L)
*Therapeutic serum levels have not been established for epilepsy.

>10 µg/mL
Coma: 30–100 µg/mL
>200 µg/mL
>80 µg/mL (>54 µmol/L)

FIGURE 6.4 Maintenance and therapeutic range for amiodarone (antiarrhythmic). (Source: Therapeutic Drug
Monitoring—Clinical Guide, 2nd edition. Abbott Laboratories, Abbott Park, IL, USA.)

FIGURE 6.5 Maintenance and therapeutic range for digitoxin (cardiac glycoside). (Source: Therapeutic Drug
Monitoring—Clinical Guide, 2nd edition. Abbott Laboratories, Abbott Park, IL, USA.)

Blood, Saliva, and Breath Alcohol Content (BAC; Ethanol [Ethyl Alcohol, ETOH])
Ethanol is absorbed rapidly from the GI tract, with peak blood levels usually occurring within 40 to 70 minutes of
ingestion on an empty stomach. Food in the stomach decreases alcohol absorption. Ethanol is metabolized by the liver to
acetaldehyde. Once peak blood ethanol levels are reached, disappearance is linear; a 70-kg man metabolizes 7 to 10
g/h of alcohol (15 + 5 mg/dL/h). Symptoms of intoxication in the presence of low alcohol levels could indicate a serious
acute medical problem requiring immediate attention.
Quantitation of alcohol level may be performed for medical or legal purposes, to diagnose alcohol intoxication, and to
determine appropriate therapy. Alcohol level must be tested as a possible cause of unknown coma because alcohol
intoxication mimics diabetic coma, cerebral trauma, and drug overdose. This test is also used to screen for alcoholism
and to monitor ethanol treatment for methanol intoxication.
Reference Values
Normal Negative: no alcohol detected <10 mg/dL or <2 mmol/L is considered negative <20 mg/dL or <4.34 mmol/L is
considered negative for the U.S. Department of Transportation (DOT) >40 mg/dL or >8.68 mmol/L is considered positive
for the U.S. DOT >80 mg/dL or >17.4 mmol/L is positive under most state drunk driving laws
Procedure
1. Obtain a 5-mL venous blood sample from the arm in living persons. From dead persons, take samples from the
aorta. Observe standard precautions.
a. Use a non–alcohol-based solution (eg, povidone-iodine) for cleansing the venipuncture site.
b. Sodium fluoride or oxalate anticoagulant is recommended. Serum can also be used.
c. Keep blood sample tightly stoppered. Do not open.
2. A 20-mL sample of urine or gastric contents can also be used. Place specimen in a biohazard bag.
3. A breath analyzer measures ethanol content at the end of expiration following a deep inspiration. (See Appendix K
for information on breath alcohol analyzers.)
Clinical Implications
1. At levels of 50 to 100 mg/dL (10.8–21.7 mmol/L), certain signs and symptoms are reported (eg, flushing, slowing of
reflexes, impaired visual acuity).
2. At levels >100 mg/dL (>21.7 mmol/L), CNS depression is reported. In many states, this is the cutoff level for driving
under the influence of alcohol.
3. Blood levels >300 mg/dL (>64.8 mmol/L) are associated with coma.
4. Death has been reported at levels >400 mg/dL (>86.4 mmol/L).
5. Properly collected urine samples will have an alcohol content similar to that of blood. Saliva samples will have an

alcohol content 1.2 times that of blood.
Interfering Factors
1. Increased blood ketones, as in diabetic ketoacidosis, can falsely elevate blood or breath test results.
2. Ingestion of other alcohols, such as isopropanol or methanol, may affect results.

Clinical Alert
1. Panic value is >300 mg/dL (>64.8 mmol/L). Report and initiate overdose treatment at once.
2. Symptoms of intoxication in the presence of low blood alcohol could indicate a serious medical problem requiring
immediate medical attention.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. Proper collection, handling, and storage of the blood alcohol specimen is
essential when the question of sobriety is raised.
2. Advise patient of legal rights in cases involving question of sobriety.
3. A witnessed, signed consent form may have to be obtained.
4. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test results and monitor as appropriate for toxic levels.
2. If alcohol levels are high, initiate treatment at once.
3. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

LIPOPROTEIN TESTS/LIPOPROTEIN PROFILES
Lipoprotein measurements are diagnostic indicators for hyperlipidemia and hypolipidemia. Hyperlipidemia is classified as
types I, Iia, Iib, III, IV, and V. Lipids are fatty substances made up of cholesterol, cholesterol esters (liquid compounds),
triglycerides, nonesterized fatty acids, and phospholipids. Lipoproteins are unique plasma proteins that transport
otherwise insoluble lipids. They are categorized as chylomicrons, ß-lipoproteins (low-density lipoproteins [LDLs]),
pre-ß-lipoproteins (very-low-density lipoproteins [VLDLs]), and a-lipoproteins (high-density lipoproteins [HDLs]).
Apolipoprotein A is mainly composed of HDL, chylomicrons, and VLDL. Apolipoprotein B is the main component of LDL.
Lipids provide energy for metabolism, serve as precursors of steroid hormones (adrenals, ovaries, testes) and bile acids,
and play an important role in cell membrane development. A lipid profile usually includes cholesterol, triglycerides, LDL,
and HDL levels.
Cholesterol
Cholesterol testing evaluates the risk for arthrosclerosis, myocardial occlusion, and coronary arterial occlusion.
Cholesterol relate to coronary heart disease (CHD) and is an important screening test for heart disease. It is part of the
lipid profiles. Elevated cholesterol levels are a major component in the hereditary hyperlipoproteinemias. Cholesterol
determinations are also frequently a part of thyroid function, liver function, renal function, and diabetes mellitus studies. It
is also used to monitor effectiveness of diet, medications, lifestyle changes (eg, exercise), and stress management.
Reference Values
Normal Normal values vary with age, diet, sex, and geographic or cultural region. Adults, fasting: Desirable level:
140–199 mg/dL or 3.63–5.15 mmol/L Borderline high: 200–239 mg/dL or 5.18–6.19 mmol/L High: >240 mg/dL or >6.20
mmol/L Children and adolescents (12–18 years): Desirable level: <170 mg/dL or <4.39 mmol/L Borderline high: 170–199
mg/dL or 4.40–5.16 mmol/L High: >200 mg/dL or >5.18 mmol/L
Procedure
1. Obtain a 5-mL venous blood sample. Fasting is required. Serum is needed.
2. Observe standard precautions. Place specimen in a biohazard bag.
Clinical Implications
1. Total blood cholesterol levels are the basis for classifying CHD risk.
a. Levels >240 mg/dL or >6.20 mmol/L are considered high and should include follow-up lipoprotein analysis.
Borderline high levels (200–239 mg/dL or 5.18–6.19 mmol/L) in the presence of CHD or two other CHD risk
factors should also include lipoprotein analysis/profiles.
b. CHD risk factors include male gender, family history, and premature CHD (MI or sudden death before age 55
years in a parent or sibling), smoking (>10 cigarettes per day), hypertension, low HDL cholesterol levels (<35
mg/dL or <0.91 mmol/L confirmed by repeat measurement), diabetes mellitus, history of definite cerebrovascular
or occlusive peripheral vascular disease, and severe obesity (>30% overweight).
c. In public screening programs, all patients with cholesterol levels >200 mg/dL or >5.18 mmol/L should be
referred to their physicians for further evaluation. Before initiating any therapy, the level should be retested.
2. Elevated cholesterol levels (hypercholesterolemia) occur in the following conditions:
a. Type II familial hypercholesterolemia
b. Hyperlipoproteinemia types I, IV, and V
c. Cholestasis

d. Hepatocellular disease, biliary cirrhosis
e. Nephrotic syndrome glomerulonephritis
f. Chronic renal failure
g. Pancreatic and prostatic malignant neoplasms
h. Hypothyroidism
i. Poorly controlled diabetes mellitus
j. Alcoholism
k. Glycogen storage disease (von Gierke's disease)
l. Werner's syndrome
m. Diet high in cholesterol and fats (“dietary affluence”)
n. Obesity
3. Decreased cholesterol levels (hypocholesterolemia) occur in the following conditions:
a. Hypo-a-lipoproteinemia
b. Severe hepatocellular disease
c. Myeloproliferative diseases
d. Hyperthyroidism
e. Malabsorption syndrome, malnutrition
f. Megaloblastic or sideroblastic anemia (chronic anemias)
g. Severe burns, inflammation
h. Conditions of acute illness, infection
i. Chorionic obstructive lung disease
j. Mental retardation
Interfering Factors
1. Estrogens decrease plasma cholesterol levels; pregnancy increases these levels.
2. Certain drugs increase or decrease cholesterol levels.
3. Seasonal variations in cholesterol levels have been observed; levels are higher in fall and winter and lower in
spring and summer.
4. Positional variations occur; levels are lower when sitting versus standing and lower when recumbent versus sitting.
5. Plasma (EDTA) values are 10% lower than serum.
Interventions
Pretest Patient Care
1. Explain test purpose and procedure. An overnight fast before testing is recommended, although nonfasting
specimens may be taken. Pretest, a normal diet should be consumed for 7 days. The patient should abstain from
alcohol for 48 hours before testing. Prolonged fasting with ketosis increases values.
2. Document drugs the patient is taking.
3. Encourage the patient to relax.
4. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test results and counsel appropriately. Cholesterol levels are influenced by heredity, diet, body weight,
and physical activity. Some lifestyle changes may be necessary to reduce elevated levels.
2. Remember that cholesterol levels >200 mg/dL (or >5.18 mmol/L) should be retested and the results averaged. If the
two results differ by >10%, a third test should be done.
3. Be aware that once hyperlipidemia has been established, the diet should be lower in animal fats and should replace
saturated fats with polyunsaturated fats. Fruits, vegetables (especially greens), and whole-grain products should be
increased. Patients with diabetes, as well as others, should seek counsel from a dietitian regarding diet
management if necessary. Therapy for hyperlipidemia should always begin with diet modification.
4. Remember that the American Heart Association and National Cholesterol Education Programs have excellent
resources for providing diet and lifestyle management information.
5. Be aware that at least 6 months of dietary therapy should be tried before initiating cholesterol-reducing drug
therapy.
6. Perform a comprehensive lipoprotein analysis if cholesterol levels are not lowered within 6 months after start of
therapy.

Clinical Alert
1. Cholesterol measurement should not be done immediately after MI. A 3-month wait is suggested.
2. >300 mg/dL or >7.8 mmol/L: there is a strong relationship to coronary heart disease, but only a fraction of those
with CAD have cholesterol increased.
High-Density Lipoprotein Cholesterol (HDL-C)
HDL-C is a class of lipoproteins produced by the liver and intestines. HDL is composed of phospholipids and one or two
apolipoproteins. It plays a role in the metabolism of the other lipoproteins and in cholesterol transport from peripheral
tissues to the liver. LDL and HDL may combine to maintain cellular cholesterol balance through the mechanism of LDL
moving cholesterol into the arteries and HDL removing it from the arteries. Decreased HDL levels are atherogenic,
whereas elevated HDL levels protect against arthrosclerosis by removing cholesterol from vessel walls and transporting it
to the liver where it is removed from the body. There is a strong relationship of HDL cholesterol and CAD.

HDL-C, the good cholesterol, is used to asses CAD risk and monitor persons with known low HDL levels. HDL-C levels
are inversely proportional to CHD risk and are a primary independent risk factor. When a slightly increased cholesterol is
due to high HDL, therapy is not indicated.
Reference Values
Normal Men: 35–65 mg/dL or 0.91–1.68 mmol/L Women: 35–80 mg/dL or 0.91–2.07 mmol/L <25 mg/dL or <0.65 mmol/L
of HDL: CHD risk at dangerous level 2 times the risk 26–35 mg/dL or 0.67–0.91 mmol/L of HDL: high CHD risk: 1.5 times
the risk 36–44 mg/dL or 0.93–1.14 mmol/L of HDL: moderate CHD risk: 1.2 times the risk 45–59 mg/dL or 1.16–1.53
mmol/L of HDL: average CHD risk 60–74 mg/dL or 1.55–1.92 mmol/L of HDL: below-average CHD risk >75 mg/dL or
>1.94 mmol/L of HDL: no risk (associated with longevity)
Procedure
1. Obtain a 5-mL venous blood sample. Fasting is necessary. The HDL is precipitated out from the total cholesterol for
analysis.
2. Calculate a cholesterol/HDL-C ration from these values.
Clinical Implications
1. Increased HDL-C values occur in the following conditions:
a. Familial hyper-a-lipoproteinemia (HDL excess)
b. Chronic liver disease (cirrhosis, alcoholism, hepatitis)
c. Long-term aerobic or vigorous exercise
2. Decreased HDL-C values are associated with increased risk for CHD and premature CHD and occur in the
following conditions:
a. Familial hypo-a-lipoproteinemia (Tangier disease), Apo C-III deficiency
b. a-ß-Lipoproteinemia
c. Hypertriglyceridemia (familial)
d. Poorly controlled diabetes mellitus
e. Hepatocellular diseases
f. Cholestasis
g. Chronic renal failure, uremia, nephrotic syndrome
h. In the United States, 3% of men have low HDL levels for unknown reasons, even though cholesterol and
triglyceride values are normal, and they are at risk for premature CAD.
Interfering Factors
1. Increased HDL level is associated with estrogen therapy, moderate intake of alcohol and other drugs (especially
androgenic and related steroids), and insulin therapy.
2. Decreased HDL levels are associated with the following:
a. Certain drugs such as steroids, antihypertensive agents, diuretics, beta blockers, triglycerides, and thiazides
b. Stress and recent illness
c. Starvation and anorexia
d. Obesity, lack of exercise
e. Smoking
f. Hypertriglyceridemia (>400 mg/dL or >10.36 mmol/L) (retest making sure the patient is properly fasting)
Interventions
Pretest Patient Care
1. Explain test purpose. A 9–12 hour fast is recommended. Alcohol should not be consumed for at least 24 hours
before test.
2. Ensure that patient is on a stable diet for 3 weeks.
3. If possible, withhold all medication for at least 24 hours before testing. Check with physician.
4. Encourage relaxation.
5. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Aftercare
1. Interpret test results and counsel appropriately (see cholesterol patient aftercare , page 423).
2. Remember that low HDL levels can be raised by diet management, exercise, weight loss, and smoking cessation.
Many resources are available through the American Heart Association and other organizations.
3. Drug therapy may be necessary if other methods fail to raise HDL levels.
4. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Clinical Alert
Cholesterol and HDL-C levels should not be done immediately after MI. A 3-month wait is suggested.

Clinical Alert
The cholesterol/HDL ratio provides more information than does either value alone. The higher the cholesterol/HDL
ratio, the greater the risk for developing atherosclerosis. This ratio should be reported with total cholesterol values,
along with the % HDL-C.

Very-Low-Density Lipoprotein (VLDL); Low-Density Lipoprotein (LDL)
Sixty to 70% of the total serum cholesterol is present in the LDL. LDLs are the cholesterol-rich remnants of the VLDL lipid
transport vehicle. Because LDL has a longer half-life (3–4 days) than its precursor VLDL, LDL is more prevalent in the
blood. It is mainly catabolized in the liver and possibly in nonhepatic cells as well. The VLDLs are major carriers of
triglycerides. Degradation of VLDL is a major source of LDL. Circulating fatty acids form triglycerides in the liver, and
these are packaged with apoprotein and cholesterol to be exported into the blood as VLDLs.
This test is specifically done to determine CHD risk. LDL, “the bad cholesterol,” is closely associated with increased
incidence of atherosclerosis and CHD. The test of choice is LDL because it has a longer half-life and it is easier to
measure.
Reference Values
Normal Adults: Desirable: <130 mg/dL or <3.4 mmol/L Borderline high-risk: 140–159 mg/dL or 3.4–4.1 mmol/L High-risk:
>160 mg/dL or >4.1 mmol/L Children and adolescents: Desirable: <110 mg/dL or <2.8 mmol/L Borderline high-risk:
110–129 mg/dL or 2.8–3.4 mmol/L High-risk: >130 mg/dL or >3.4 mmol/L
Procedure
1. Use the following equation for VLDL calculated (estimation): triglycerides divided by 5.
2. Calculate LDL cholesterol levels by using the Friedwald's formula:

3. Remember that the formula is valid only if the cholesterol and triglyceride values are from a fasting specimen and
the triglyceride value is >400 mg/dL or >10.4 mmol/L.
4. Lipoprotein analysis measures fasting levels of total cholesterol, total triglycerides, and HDL cholesterol. Calculate
LDL cholesterol from these values.
5. Remember that there is a nondirect test for LDH that may be ordered if triglycerides are >400 mg/dL or >10.4
mmol/L.
Clinical Implications
1. Increased LDL levels are caused by the following conditions:
a. Familial type 2 hyperlipidemia, familial hypercholesterolemia
b. Secondary causes include the following:
1. Diet high in cholesterol and saturated fat
2. Hyperlipidemia secondary to hypothyroidism
3. Nephrotic syndrome
4. Multiple myeloma and other dysglobulinemias
5. Hepatic obstruction or disease
6. Anorexia nervosa
7. Diabetes mellitus
8. Chronic renal failure
9. Porphyria
10. Premature CHD
2. Decreased LDL levels occur in the following conditions:
a. Hypolipoproteinemia
b. Tangier disease
c. Type I hyperlipidemia
d. Apo C-II deficiency
e. Hyperthyroidism
f. Chronic anemias
g. Severe hepatocellular disease
h. Reye's syndrome
i. Acute stress (burns, illness)
j. Inflammatory joint disease
k. Chronic pulmonary disease
Interfering Factors
1. Increased LDLs are associated with pregnancy and certain drugs such as steroids, progestins, and androgens (see
Appendix J).
2. Not fasting may cause false elevation.
3. Decreased LDLs are found in women taking oral estrogen therapy.
Interventions
Pretest Patient Care
1. Explain test purpose. A 9–12 hour fast is recommended. Alcohol should not be consumed for at least 24 hours
before test.
2. Remember that patient should ideally be on a stable diet for 3 weeks.
3. If possible, withhold all medication for at least 24 hours before testing. Check with physician.
4. Encourage relaxation.
5. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Aftercare
1. Interpret test results and counsel appropriately about results and need for further testing.
2. If patient has high LDH levels, repeat the test in 2 to 8 weeks and average the values to establish an accurate
baseline from which to devise a treatment plan ( Table 6.14).
Table 6.14 Stages of Treatment for High LDH Levels

DIETARY TREATMENT
Without CHD or two other
risk factors
With CHD or two other
risk factors
DRUG TREATMENT
Without CHD or two other
risk factors
With CHD or two other
risk factors

Initiation Level

Minimal Goal

>160 mg/dL (>4.1