1.Copyright 2003 F.A. Davis CompanyNurses Manual of Laboratory and Diagnostic Tests EDITION Bonita Morrow Cavanaugh, PhD, RNClinical Nurse Specialist Nursing EducationThe Childrens Hospital Denver, Colorado Clinical FacultyUniversity of ColoradoHealth Sciences CenterSchool of NursingDenver, Colorado Affiliate ProfessorUniversity of Northern Colorado School of Nursing Greeley, ColoradoF.A. Davis Company Philadelphia

2. Copyright 2003 F.A. Davis CompanyF. A. Davis Company1915 Arch StreetPhiladelphia, PA 19103www.fadavis.comCopyright 2003 by F. A. Davis CompanyCopyright 1999, 1995, 1989 by F. A. Davis Company. All rights reserved. This book is protected by copyright. No part of itmay be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photo-copying, recording, or otherwise, without written permission from the publisher.Printed in the United States of AmericaLast digit indicates print number: 10 9 8 7 6 5 4 3 2 1Publisher: Lisa DeitchDevelopmental Editor: Diane BlodgettCover Designer: Louis J. ForgioneAs new scientific information becomes available through basic and clinical research, recommended treatments and drugtherapies undergo changes. The author and publisher have done everything possible to make this book accurate, up to date,and in accord with accepted standards at the time of publication. The author, editors, and publisher are not responsible forerrors or omissions or for consequences from application of the book, and make no warranty, expressed or implied, in regardto the contents of the book. Any practice described in this book should be applied by the reader in accordance with professionalstandards of care used in regard to the unique circumstances that may apply in each situation. The reader is advised always tocheck product information (package inserts) for changes and new information regarding dose and contraindications beforeadministering any drug. Caution is especially urged when using new or infrequently ordered drugs. Library of Congress Cataloging-in-Publication DataCavanaugh, Bonita Morrow, 1952Nurses manual of laboratory and diagnostic tests. 4th ed. /Bonita Morrow Cavanaugh.p. cm. Rev. ed. of: Nurses manual of laboratory and diagnostic tests /Juanita Watson. 3rd. ed. c1995. Includes bibliographical references and index. ISBN 0-8036-1055-6 (pbk.) 1. Diagnosis, Laboratory Handbooks, manuals, etc. 2. Nursing-Handbook, manuals, etc. I. Watson, Juanita,1946 Nurses manual of laboratory and diagnostic tests. II. Title. [DNLM: 1. Laboratory Techniques and Procedures nurses instructionhandbooks. QY 39 C377n 1999]RT48.5.W38 1999616.075dc21DNLM/DLCfor Library of Congress 98-50920CIPAuthorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted byF. A. Davis Company for users registered with the Copyright Clearance Center (CCC) Transactional Reporting Service, providedthat the fee of $.10 per copy is paid directly to CCC, 222 Rosewood Drive, Danvers, MA 01923. For those organizations thathave been granted a photocopy license by CCC, a separate system of payment has been arranged. The fee code for users of theTransactional Reporting Service is: 8036-1055/03 0 + $.10. 3. Copyright 2003 F.A. Davis CompanyTo Laurie ONeil Good, the finest nurse I have ever known.Love, Bonnie 4. Copyright 2003 F.A. Davis Company This page intentionally left blank 5. Copyright 2003 F.A. Davis CompanyPreface This book is designed to provide both students and practitioners of nursing with the informa- tion they need to care for individuals undergoing laboratory and diagnostic tests and proce- dures. The content is presented as a guiding reference for planning care, providing specific interventions, and evaluating outcomes of nursing care.In this edition, the background information and description of the test or procedure are followed directly by the clinical applications data, starting with reference values, for each test or group of tests.The introductory sections include the anatomic, physiological, and pathophysiological content necessary for a thorough understanding of the purpose of and indications for specific tests and procedures. The inclusion of this information makes this book unlike many other references on this subject matter. This feature enhances the integration of basic science knowl- edge with an understanding of and application to diagnostic testing. This is extremely helpful for nursing students in developing critical thinking and clinical judgment.For each test or study within the respective sections, reference values, including variations related to age or gender, are provided. Critical values, where appropriate, are highlighted. Both conventional units and international units are provided. Readers are encouraged to be aware of some variation in laboratory values from agency to agency.For all tests, interfering factors are noted where appropriate. Contraindications and Nursing Alerts are included to provide information crucial to safe and reliable testing and nursing care.Other features of this manual that contribute to its practical use are presentation of detailed content in tabular format when appropriate and the use of appendices to provide essential information applicable to most, if not all, tests and procedures.Every effort has been made to include tests and procedures currently in use in practice settings. It is recognized that newer tests and procedures may have become available after this manuscript was prepared. Readers are encouraged to keep abreast of current literature and consult with laboratories and agencies in their area for new developments in the field of diag- nostic tests. BONITA MORROW CAVANAUGH v 6. Copyright 2003 F.A. Davis Company This page intentionally left blank 7. Copyright 2003 F.A. Davis CompanyAcknowledgments This book would not have been possible without the help, support, and encouragement of a number of people. Special appreciation is due to the staff of the F. A. Davis Company. I am particularly indebted to Lisa Deitch, Publisher, for her major contribution in developing the unique format of this text, for her encouragement, and for always being available for help when I needed it. I would also like to acknowledge Robert Martone, Nursing Publisher, who encour- aged me to pursue this project, and Robert H. Craven, Jr., President, for his support and patience as the book evolved. Special thanks are also due to Ruth De George, Editorial Assistant, and Michele Reese, Editorial Aide, for their invaluable assistance. Many other individuals at the F. A. Davis Company contributed to the production of this book, and I wish to extend to all of them my sincere appreciation for their expertise and dedication to the high standards necessary to produce a good book. Special recognition in this regard is due to Jessica Howie Martin, Production Editor, and Bob Butler, Director of Production.I thank the consultants who served as reviewers of the manuscript for their thoroughness and generosity in sharing their ideas and suggestions. Your comments proved invaluable! Finally, a special thanks to those family members, friends, and associates who offered and gave their support, patience, and encouragement.B.M.C. vii 8. Copyright 2003 F.A. Davis Company This page intentionally left blank 9. Copyright 2003 F.A. Davis CompanyConsultants Janice Brownlee, BScN, MAEdDolores Philpot, BSMT, AND, MSN ProfessorInstructor Canadore College of Applied Arts and University of Tennessee Technology Knoxville, Tennessee North Bay, Ontario, CanadaSylvan L. Settle, RN Marie Colucci, BS, MS, EdD Vocational Teacher Associate ProfessorTennessee Technology Center Riverside Community CollegeMemphis, Tennessee Riverside, CaliforniaJoyce Taylor, RN, MSN, DSN, BA Mary Jo Goolsby, MSN, ARNP, EdDAssociate Professor Instructor Henderson State University Florida State University Arkadelphia, Arkansas Tallahassee, FloridaShelley M. Tiffin, ART (CSMLS), BMLSc Shelby Hawk, RN, MSN Bachelor of Medical Laboratory Science Instructor Program Mid Michigan Community College Department of Pathology and Laboratory Harrison, Michigan MedicineUniversity of British Columbia Priscilla Innocent, RN, MSNVancouver, British Columbia, Canada Associate Professor Indiana Wesleyan UniversityDonna Yancey, BSN, MSN, DNS Marion, IndianaAssistant ProfessorPurdue University Dr. Fran Keen, RN, DNScWest Lafayette, Indiana Associate Professor University of Miami Coral Gables, Florida ix 10. Copyright 2003 F.A. Davis Company This page intentionally left blank 11. Copyright 2003 F.A. Davis Company Contents SECTION I Laboratory Tests, 1 CHAPTER 1 Hematology and Tests of Hematopoietic Function ......................................................................3 CHAPTER 2 Hemostasis and Tests of Hemostatic Functions ........................................................................39 CHAPTER 3 Immunology and Immunologic Testing ........................................................................................60 CHAPTER 4 Immunohematology and Blood Banking......................................................................................96 CHAPTER 5 Blood Chemistry..............................................................................................................................103 CHAPTER 6 Studies of Urine ..............................................................................................................................221 CHAPTER 7 Sputum Analysis ............................................................................................................................268 CHAPTER 8 Cerebrospinal Fluid Analysis ......................................................................................................274 CHAPTER 9 Analysis of Effusions ....................................................................................................................283 CHAPTER 10 Amniotic Fluid Analysis ................................................................................................................297 CHAPTER 11 Semen Analysis ..............................................................................................................................305 CHAPTER 12 Analysis of Gastric and Duodenal Secretions..........................................................................311xi 12. Copyright 2003 F.A. Davis CompanyxiiContents CHAPTER 13 Fecal Analysis ................................................................................................................................321 CHAPTER 14 Analysis of Cells and Tissues ......................................................................................................332 CHAPTER 15 Culture and Sensitivity Tests........................................................................................................352 SECTION II Diagnostic Tests and Procedures, 361 CHAPTER 16 Endoscopic Studies........................................................................................................................363 CHAPTER 17 Radiologic Studies ........................................................................................................................397 CHAPTER 18 Radiologic Angiography Studies ................................................................................................438 CHAPTER 19 Ultrasound Studies ........................................................................................................................458 CHAPTER 20 Nuclear Scan and Laboratory Studies ......................................................................................482 CHAPTER 21 Non-Nuclear Scan Studies ..........................................................................................................528 CHAPTER 22 Manometric Studies ......................................................................................................................545 CHAPTER 23 Electrophysiologic Studies ..........................................................................................................558 CHAPTER 24 Studies of Specific Organs or Systems......................................................................................577 CHAPTER 25 Skin Tests ........................................................................................................................................615 APPENDICES APPENDIX I Obtaining Various Types of Blood Specimens..........................................................................625 APPENDIX II Obtaining Various Types of Urine Specimens ..........................................................................631 APPENDIX III Guidelines for Isolation Precautions in Hospitals ..................................................................634 APPENDIX IV Units of Measurement (Including SI Units) ..............................................................................636 13. Copyright 2003 F.A. Davis CompanyContentsxiii APPENDIX V Profile or Panel Groupings and Laboratory Tests ....................................................................644 APPENDIX VI Nursing Care Plan for Individuals Experiencing Laboratory and Diagnostic Testing ............................................................................................649 INDEX..............................................................................................................................................651 14. Copyright 2003 F.A. Davis Company SECTIONLaboratoryTests 1 15. Copyright 2003 F.A. Davis Company This page intentionally left blank 16. Copyright 2003 F.A. Davis CompanyCHAPTERHematology and Tests ofHematopoietic FunctionTESTS COVEREDBone Marrow Examination, 7Stained Red Blood CellReticulocyte Count, 9 Examination, 24Iron Studies, 11Hemoglobin Electrophoresis, 26Vitamin B12 and Folic Acid Studies, 13Osmotic Fragility, 29Complete Blood Count, 14Red Blood Cell Enzymes, 30Erythrocyte (RBC) Count, 20 Erythrocyte Sedimentation Rate, 31Hematocrit, 21White Blood Cell Count, 33Hemoglobin, 21Differential White Blood Cell Count, 34Red Blood Cell Indices, 22White Blood Cell Enzymes, 37INTRODUCTION Blood constitutes 6 to 8 percent of total body weight. In terms ofvolume, women have 4.5 to 5.5 L of blood and men 5 to 6 L. In infants and children, bloodvolume is 50 to 75 mL/kg in girls and 52 to 83 mL/kg in boys. The principal functions of bloodare the transport of oxygen, nutrients, and hormones to all tissues and the removal of meta-bolic wastes to the organs of excretion. Additional functions of blood are (1) regulation oftemperature by transfer of heat to the skin for dissipation by radiation and convection, (2)regulation of the pH of body fluids through the buffer systems and facilitation of excretion ofacids and bases, and (3) defense against infection by transportation of antibodies and othersubstances as needed. Blood consists of a fluid portion, called plasma, and a solid portion that includes red bloodcells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). Plasma makesup 45 to 60 percent of blood volume and is composed of water (90 percent), amino acids,proteins, carbohydrates, lipids, vitamins, hormones, electrolytes, and cellular wastes.1 Of thesolid or cellular portion of the blood, more than 99 percent consists of red blood cells.Leukocytes and thrombocytes, although functionally essential, occupy a relatively small portionof the total blood cell mass.2 Erythrocytes remain within the blood throughout their normal life span of 120 days, trans-porting oxygen in the hemoglobin component and carrying away carbon dioxide. Leukocytes,while they are in the blood, are merely in transit, because they perform their functions in bodytissue. Platelets exert their effects at the walls of blood vessels, performing no known functionin the bloodstream itself.3 Hematology is traditionally limited to the study of the cellular elements of the blood, theproduction of these elements, and the physiological derangements that affect their functions.Hematologists also are concerned with blood volume, the flow properties of blood, and thephysical relationships of red cells and plasma. The numerous substances dissolved or suspendedin plasma fall within the province of other laboratory disciplines.43 17. Copyright 2003 F.A. Davis Company 4 SECTION ILaboratory Tests HEMATOPOIESIScapability of becoming an erythrocyte, a leukocyte,or a thrombocyte. In the adult, stem cells in Hematopoiesis is the process of blood cell formation.hematopoietic sites undergo a series of divisions and In normal, healthy adults, blood cells are manufac-maturational changes to form the mature cells tured in the red marrow of relatively few bones, found in the blood (Fig. 12). As they achieve the notably the sternum, ribs, vertebral bodies, pelvicblast stage, stem cells are committed to becoming bones, and proximal portions of the humerus anda specific type of blood cell. This theory also explains the femur. This production is in contrast to thatthe origin of the several types of white blood cells taking place in the embryo, in which blood cells are (neutrophils, monocytes, eosinophils, basophils, and derived from the yolk sac mesenchyme. As the fetus lymphocytes). As the cells mature, they lose their develops, the liver, the spleen, and the marrow cavi-ability to reproduce and cannot further divide to ties of nearly all bones become active hematopoietic replace themselves. Thus, there is a need for contin- sites (Fig. 11). In the newborn, hematopoiesisuous hematopoietic activity to replenish worn-out occurs primarily in the red marrow, which is found or damaged blood cells. in most bones at that stage of development. Erythropoiesis, the production of red blood cells Beginning at about age 5 years, the red marrow is(RBCs), and leukopoiesis, the production of white gradually replaced by yellowish fat-storage cellsblood cells (WBCs), are components of the (yellow marrow), which are inactive in the hematopoietic process. Erythropoiesis maintains a hematopoietic process. By adulthood, blood cellpopulation of approximately 251012 circulating production normally occurs in only those bones thatRBCs, or an average of 5 million erythrocytes per retain red marrow activity.5 cubic millimeter of blood. The production rate isAdult reticuloendothelial cells retain the potentialabout 2 million cells per second, or 35 trillion cells for hematopoiesis, although in the healthy state per day. With maximum stimulation, this rate can be reserve sites are not activated. Under conditions of increased sixfold to eightfold, or one volume per day hematopoietic stress in later life, the liver, the spleen, equivalent to the cells contained in 0.5 pt of whole and an expanded bone marrow may resume the blood. production of blood cells.The level of tissue oxygenation regulates theAll blood cells are believed to be derived from the production of RBCs; that is, erythropoiesis occurs in pluripotential stem cell,6 an immature cell with the response to tissue hypoxia. Hypoxia does not, Figure 11. Location of active marrow growth in the fetus and adult. (From Hillman, RS, and Finch, CA: Red Cell Manual, ed 7. FA Davis, Philadelphia, 1996, p 2, with permission.) 18. Copyright 2003 F.A. Davis CompanyCHAPTER 1Hematology and Tests of Hematopoietic Function 5 Image/Text rights unavailablehowever, directly stimulate the bone marrow.tion of erythrocytes; (2) reduces the time requiredInstead, RBC production occurs in response to for cells to enter the circulation, thereby increasingerythropoietin, precursors of which are found prima-the number of circulating immature erythrocytesrily in the kidney and to a lesser extent in the liver. such as reticulocytes (see Fig. 12); and (3) facilitatesWhen the renal oxygen level falls, an enzyme, renal the incorporation of iron into RBCs. When theerythropoietic factor, is secreted. This enzyme reactsnumber of produced erythrocytes meets the bodyswith a plasma protein to form erythropoietin, which tissue oxygenation needs, erythropoietin release andsubsequently stimulates the bone marrow toRBC production are reduced. Table 11 lists causesproduce more RBCs. Specifically, erythropoietin (1) of tissue hypoxia that may stimulate the release ofaccelerates production, differentiation, and matura-erythropoietin. TABLE 11 Causes of Tissue Hypoxia That May Stimulate Erythropoietin Release Acute blood loss Impaired oxygencarbon dioxide exchange in the lungs Low hemoglobin levels Impaired binding of oxygen to hemoglobin Impaired release of oxygen from hemoglobin Excessive hemolysis of erythrocytes due to hypersplenism or hemolytic disorders of antibody, bacterial, or chemical origin Certain anemias in which abnormal red blood cells are produced (e.g., hereditary spherocytosis) Compromised blood flow to the kidneys 19. Copyright 2003 F.A. Davis Company 6 SECTION ILaboratory TestsThreats to normal erythropoiesis occur if suffi- folic acid are required for DNA synthesis and are cient amounts of erythropoietin cannot be needed by all cells for growth and reproduction; produced or if the bone marrow is unable to because cellular reproduction occurs at such a high respond to erythropoietic stimulation. People with- rate in erythropoietic tissue, formation of RBCs is out kidneys or with severe impairment of renalparticularly affected by a deficiency of either of these function are unable to produce adequate amounts ofsubstances. Iron is needed for hemoglobin synthesis renal erythropoietic factor. In these individuals, theand normal RBC production. In addition to dietary liver is the source of erythropoietic factor. The quan- sources, iron from worn-out or damaged RBCs is tity produced, however, is sufficient to maintain onlyavailable for reuse in erythropoiesis.7 a fairly stable state of severe anemia that responds Leukopoiesis, the production of WBCs, maintains minimally to hypoxemia. a population of 5,000 to 10,000 leukocytes per cubicInadequate erythropoiesis may occur also if themillimeter of blood, with the capability for rapid bone marrow is depressed because of drugs, toxicand dramatic change in response to a variety of chemicals, ionizing radiation, malignancies, or other stimuli. No leukopoietic substance comparable to disorders such as hypothyroidism. Also, in certainerythropoietic factor has been identified, but many anemias and hemoglobinopathies, the bone marrow factors are known to influence WBC production, is unable to produce sufficient normal erythrocytes.with a resultant excess (leukocytosis) or deficiencyOther substances needed for erythropoiesis are (leukopenia) in leukocytes (Table 12). vitamin B12, folic acid, and iron. Vitamin B12 and Note that WBC levels vary in relation to diurnalTABLE 12 Causes of Altered Leukopoiesis PhysiologicalPathologicalLeukocytosisPregnancyAll types of infectionEarly infancyAnemiasEmotional stress Cushings diseaseStrenuous exercise Erythroblastosis fetalisMenstruation LeukemiasExposure to cold Polycythemia veraUltraviolet lightTransfusion reactionsIncreased epinephrine secretionInflammatory disorders Parasitic infestationsLeukopeniaDiurnal rhythmsBone marrow depression Toxic and antineoplastic drugs Radiation Severe infection Viral infections Myxedema Lupus erythematosus and other autoimmune disorders Peptic ulcers Uremia Allergies Malignancies Metabolic disorders Malnutrition 20. Copyright 2003 F.A. Davis CompanyCHAPTER 1Hematology and Tests of Hematopoietic Function 7rhythms; thus, the time at which the sample iscare units, and community and home care settings.obtained may influence the results. Overall, leuko- A detailed description of procedures for obtain-cytes may increase by as many as 2000 cells per milli-ing peripheral blood samples is provided inliter from morning to evening, with a corresponding Appendix I.overnight decrease. Eosinophils decrease until aboutnoon and then rise to peak between midnight and 3BONE MARROW EXAMINATIONAM. This variation may be related to adrenocorticalhormone levels, which peak between 4 and 8 AM,Bone marrow examination (aspiration, biopsy)because an increase in these hormones can cause requires removal of a small sample of bone marrowcirculating lymphocytes and eosinophils to disap- by aspiration, needle biopsy, or open surgical biopsy.pear in a few hours.Cells normally present in hematopoietic marrowinclude erythrocytes and granulocytes (neutrophils,basophils, and eosinophils) in all stages of matura-Evaluation of Hematopoiesistion; megakaryocytes (from which plateletsAbnormal results of studies such as a completedevelop); small numbers of lymphocytes; and occa-blood count (CBC)) and WBC count and differen-sional plasma cells (Fig. 12). Nucleated WBCs intial indicate the need to determine the individualsthe bone marrow normally outnumber nucleatedhematopoietic function. Evaluation of hemato- (immature) RBCs by about 3:1. This is called thepoiesis begins with the examination of a bone myeloid-to-erythroid (M:E) ratio.8 Causes ofmarrow sample and may subsequently require otherincreased and decreased values on bone marrowstudies and a sample of peripheral blood, eitherexamination are presented in Table 13.venous or capillary. Various stains followed by microscopic examina- Although the collection of blood specimens istion can be performed on bone marrow aspirate tousually the responsibility of the laboratory techni-diagnose and differentiate among the differentcian or phlebotomist, it is often the responsibilitytypes of leukemia. A Sudan B stain differentiatesof the nurse in emergency departments, critical between acute granulocytic and lymphocytic TABLE 13 Causes of Alterations in Bone Marrow Cells Cell Type Increased ValuesDecreased Values ReticulocytesCompensated RBC lossAplastic crisis of sickle cell disease or hereditary spherocytosisResponse to vitamin B12 therapy Aplastic anemia Neutrophils (total)Myeloid (chronic) leukemias Leukemias (monocytic and lymphoblastic)Acute myeloblastic leukemia LymphocytesLymphatic leukemiaLymphosarcomaLymphomasMononucleosisAplastic anemia Plasma cells Myeloma NormoblastsPolycythemia vera Deficiency of folic acid or vitamin B12Aplastic anemiaHemolytic anemia EosinophilsBone marrow carcinomaLymphadenomaMyeloid leukemia 21. Copyright 2003 F.A. Davis Company 8SECTION ILaboratoryTests leukemia. A periodic acidSchiff stain assists inMonitoring of bone marrow response to antineo- the diagnosis of acute lymphocytic leukemia andplastic or radiation therapy for malignancies erythroleukemia. A terminal deoxynucleotidyl Evaluation of hepatomegaly (enlarged liver) or transferase test differentiates between lymphoblasticsplenomegaly (enlarged spleen) leukemia and lymphoma.9Identification of bone marrow hyperplasia orBecause bone marrow examination involves an hypoplasia, although the study may not indicate invasive procedure with risks of infection, trauma,the cause of the quantitative abnormality and bleeding, a signed consent is required.Determination of marrow differential (propor-tion of the various types of cells present in the INDICATIONS FOR BONE MARROWmarrow) and M:E ratio EXAMINATIONDiagnosis of various disorders associated withEvaluation of abnormal results of CBC (e.g.,abnormal hematopoiesis:anemia), of WBC count with differential (e.g., Multiple myelomaincreased numbers of leukocyte precursors), or ofMost leukemias, both acute and chronicboth tests Disseminated infections (granulomatous,Monitoring of effects of exposure to bone marrow bacterial, fungal)depressantsLipid or glycogen storage diseasesReference ValuesCell Type (%)AdultsInfants Children Undifferentiated01.0 Reticulocytes0.52.5 Neutrophils (total)56.5 32.4 57.1 Myeloblasts0.35.00.621.2 Promyelocytes1.48.00.761.4 Myelocytes 4.215.02.5 18.4 Neutrophilic 5.019.0 Eosinophilic 0.53.0 Basophilic00.5 Bands (stabs) 13.034.0 14.1 0 Lymphocytes 14.016.0 49.0 16.0 Monocytes0.36.0 Plasma cells 0.33.90.020.4 Megakaryocytes 0.13.00.050.1 M:E ratio 2.33.5:1 4.4:1 2.9:1 Pronormoblasts 0.21.3 0.10.5 Normoblasts25.68.0 23.1 Basophilic 1.44.00.341.7 Polychromatophilic 6.029.06.9 18.2 Orthochromic 1.04.60.542.7 Eosinophils0.53.0 2.63.6 Basophils 00.2 0.07 0.06 Note: There may be differences in normal values among individuals and in values obtained by different laboratory techniques. 22. Copyright 2003 F.A. Davis Company CHAPTER 1Hematology and Tests of Hematopoietic Function9 Hypoplastic anemia (which may be caused bypreferred. In adults, the sternum or iliac crests are chronic infection, hypothyroidism, chronicthe preferred sites. renal failure, advanced liver disease, and a The prone or side-lying position is used if the number of idiopathic conditions)spinous processes are the sites to be used. (These Erythropoietic hyperplasia (which may besites are preferred if more than one specimen is to be caused by iron deficiency, thalassemias, hemo-obtained.) The client may also be sitting, supported globinopathies, disorders of folate and vitamin by a pillow on an overbed table for a spinous process B12 metabolism, hypersplenism, glucose-6- site. The side-lying position is used if the iliac crest phosphate dehydrogenase [G-6-PD] deficiency,or tibia is the site. For sternal punctures, the supine hereditary spherocytosis, and antibody-medi-position is used. ated bacterial or chemical hemolysis)The skin is prepared with an antiseptic solution, Lupus erythematosus draped, and anesthetized, preferably with procaine, Porphyria erythropoietica which is painless when injected. Asepsis must be Parasitic infestationsmeticulous to prevent systemic infection. AmyloidosisFor aspiration, a large needle with stylet is Polycythemia vera advanced into the marrow cavity. Penetration of the Aplastic anemia (which may be caused by drugperiosteum is painful. The stylet is removed and a toxicity, idiopathic marrow failure, or infec-syringe is attached to the needle. An aliquot of 0.5 tion) mL of marrow is withdrawn. At this time, the discomfort is a pulling sensation rather than pain.CONTRAINDICATIONSThe needle is removed and pressure applied to the Known coagulation defects, although the test maysite. The aspirate is immediately smeared on slides be performed if the importance of the informa-and, when dry, sprayed with a fixative. tion to be obtained outweighs the risks involved For needle biopsy, the local anesthetic is intro- in carrying out the testduced deeply enough to include the periosteum. A special cutting biopsy needle is introduced throughNURSING CARE BEFORE THE PROCEDUREa small skin incision and bored into the marrow cavity. A core needle is introduced through theExplain to the client: cutting needle and a plug of marrow is removed. TheThe purpose of the study needles are withdrawn and the specimen placed in aThat it will be done at the bedside by a physician preservative solution. Pressure is applied to the siteand requires about 20 minutes for 5 to 10 minutes and a dressing applied.The general procedure, including the sensationsto be expected (momentary pain as the skin isNURSING CARE AFTER THE PROCEDUREinjected with local anesthetic and again as the Care and assessment after the procedure includeneedle penetrates the periosteum, the pulling assisting the client to lie on the biopsied side, ifsensation as the specimen is withdrawn) the iliac crest was entered, or supine, if the verte-That discomfort will be minimized with local bral bodies were used, to maintain pressure on theanesthetics or systemic analgesics site for 10 to 15 minutes.That the site may remain tender for several weeks For sternal punctures, place the client in theEnsure that a signed consent has been obtained. supine position or other position of comfort.Then: Provide bed rest for at least 30 minutes after theTake and record vital signs. procedure.Provide a hospital gown if necessary to provide Assess puncture site every 10 to 15 minutes foraccess to the biopsy site or to prevent soiling of bleeding. Apply an ice bag to the puncture site tothe clients clothes with the solution used for skin alleviate discomfort and prevent bleeding.preparation. Assess for infection at the site; note any redness,Administer premedication prescribed for pain or swelling, or drainage.anxiety. Administer analgesics to alleviate discomfort.THE PROCEDURE RETICULOCYTE COUNTThe client is assisted to the desired position depend-ing on the site to be used. In young children, the Reticulocytes are immature RBCs. As RBC precur-most frequently chosen site is the proximal tibia; insors mature (Fig. 12), the cell nucleus decreases inolder children, vertebral bodies T10 to L4 are size and eventually becomes a dense, structureless 23. Copyright 2003 F.A. Davis Company 10 SECTION ILaboratory Tests mass.10 At the same time, the hemoglobin content of A normal response is indicated by an increase the cell increases. Reticulocytes are cells that have in the reticulocyte count. lost their nuclei but still retain fragments of mito- Failure of the reticulocyte count to increase chondria and other organelles. They also are slightly may indicate depressed bone marrow function- larger than mature RBCs.11 RBCs normally enter theing, defective erythropoietin production, or circulation as reticulocytes and attain the maturedefective hemoglobin production. form (erythrocytes) in 1 to 2 days. Evaluation of anemia of unknown etiology toUnder the stress of anemia or hypoxia, andetermine the type of anemia: increased output of erythropoietin may lead to an Elevated reticulocyte counts are found in increased number of circulating reticulocytes (seehemolytic anemias and sickle cell disease. Table 11). The extent of such an increase dependsDecreased counts are seen in pernicious on the functional integrity of the bone marrow, the anemia, thalassemia, aplastic anemia, and severity and duration of anemia or hypoxia, the severe iron-deficiency anemia. adequacy of the erythropoietin response, and theMonitoring response to therapy for anemia: amount of available iron.12 For example, a normal In iron-deficiency anemia, therapeutic admin- reticulocyte count in the presence of a normalistration of iron should produce reticulocytosis hemoglobin level indicates normal marrow activity,within 3 days and the count should remain whereas a normal reticulocyte count in the presence elevated until normal hemoglobin levels are of a low hemoglobin level indicates an inadequate achieved. response to anemia. This may be a result of defective Vitamin B12 therapy for pernicious anemia erythropoietin production, bone marrow function,should cause a prompt, continuing reticulocy- or hemoglobin formation. After blood loss or effec- tosis. tive therapy for certain kinds of anemia, an elevated Monitoring physiologic response to blood loss: reticulocyte count (reticulocytosis) indicates that After a single hemorrhagic episode, reticulocy- the bone marrow is normally responsive and is tosis should begin within 24 to 48 hours and attempting to replace cells lost or destroyed.peak in 4 to 7 days. Individuals with defects of RBC maturation andPersistent reticulocytosis or a second rise in the hemoglobin production may show a low reticulo-count indicates continuing blood loss. cyte count (reticulocytopenia) because the cellsConfirmation of aplastic crisis in clients with never mature sufficiently to enter the peripheral known aplastic anemia as evidenced by a drop in circulation.the usually high level of reticulocytes, indicatingPerforming a reticulocyte count involves examin- that RBC production has stopped despite contin- ing a stained smear of peripheral blood to determineuing RBC destruction13 the percentage of reticulocytes in relation to theNURSING CARE BEFORE THE PROCEDURE number of RBCs present. Client preparation is the same as that for any studyReference Values involving the collection of a peripheral blood sample (see Appendix I).Newborns 3.2% of RBCs, declining by 2 mo THE PROCEDUREInfants25%If the client is an adult, a venipuncture is performed and the sample is collected in a lavender-toppedChildren 0.54%tube. A capillary sample may be obtained in infantsAdults 0.52% of RBCs; can beand children as well as in adults for whom venipunc- higher in pregnantture may not be feasible. women NURSING CARE AFTER THE PROCEDUREReticulocyte index 1.0 Care and assessment after the procedure are theCritical values 20% increase same as for any study involving the collection of a peripheral blood sample (see Appendix I). Abnormal values: Note and report fatigue, weak- ness, and color changes associated with a decrease INDICATIONS FOR RETICULOCYTE COUNT in counts and pain, and changes in mental stateEvaluation of the adequacy of bone marrowand visual perception associated with an increaseresponse to stressors such as anemia or hypoxia: in counts. Increased counts in 4 to 7 days indicate 24. Copyright 2003 F.A. Davis CompanyCHAPTER 1Hematology and Tests of Hematopoietic Function 11 that the therapy to treat loss of RBCs is effective, techniques or indirectly by exposure of the serum to whereas decreased counts indicate an ineffective sufficient excess iron such that all the transferrin production of RBCs, and further testing and eval-present can combine with the added iron. The latter uation are needed to determine the cause. Assess result is expressed as total iron-binding capacity for continuing blood loss (pulse, blood pressure,(TIBC). The percentage saturation is calculated by skin color, weakness, dizziness).dividing the serum iron value by the TIBC value. Critical values: Polycythemia with reticulocyteFERRITIN increases of greater than 20 percent requires immediate communication to the physician.Iron is stored in the body as ferritin or hemosiderin. Prepare the client for possible phlebotomy toMany individuals who are not anemic and who can reduce volume of blood and intravenous fluidsadequately synthesize hemoglobin may still have to reduce viscosity of blood. Administer decreased iron stores. For example, menstruating ordered myelosuppressive drugs.women, especially those who have borne children,usually have less storage iron. In contrast, personswith disorders of excess iron storage such asIRON STUDIEShemochromatosis or hemosiderosis have extremelyIron plays a principal role in erythropoiesis, becausehigh serum ferritin levels.16it is necessary for proliferation and maturation ofSerum ferritin levels are used to measure iron-RBCs and for hemoglobin synthesis. Of the bodysstorage status and are obtained by either radioim-normal 4 g of iron (somewhat less in women), aboutmunoassay or enzyme-linked immunoassay. The65 percent resides in hemoglobin and about 3amount of ferritin in the circulation usually ispercent in myoglobin. A tiny but vital amount ofproportional to the amount of storage iron (ferritiniron is found in cellular enzymes, which catalyze the and hemosiderin) in body tissues. Note that serumoxidation and reduction of iron. The remainder is ferritin levels vary according to age and gender (Fig.stored in the liver, bone marrow, and spleen as 13).ferritin or hemosiderin.14INDICATIONS FOR IRON STUDIES Except for blood transfusions, the only way ironenters the body is orally. Normally, only about 10Anemia of unknown etiology to determine causepercent of ingested iron is absorbed, but up to 20and type of anemia:percent or more can be absorbed in cases of iron- Decreased serum iron with increased transfer-deficiency anemia. The body is never able to absorb rin levels is seen in iron-deficiency anemia andall ingested iron, no matter how great its need for blood loss.iron. In addition to dietary sources, iron from worn- Decreased serum iron and decreased transfer-out or damaged RBCs is available for reuse in rin levels may be seen in disorders involvingerythropoiesis.15 diminished protein synthesis or defects iniron absorption (e.g., chronic diseases,SERUM IRON, TRANSFERRIN, AND TOTALinfections, widespread malignancy, malabsorp-IRON-BINDING CAPACITY tion syndromes, malnutrition, nephroticAny iron present in the serum is in transit among the syndrome). Percentage saturation of transferrinalimentary tract, bone marrow, and available iron-storage forms. Iron travels in the bloodstreambound to transferrin, a protein ( -globulin) manu-factured by the liver. Unbound iron is highly toxic tothe body, but generally much more transferrin isavailable than that needed for iron transport.Usually, transferrin is only 30 to 35 percent satu-rated, with a normal range of 20 to 55 percent. Ifexcess transferrin is available in relation to bodyiron, the percentage saturation is low. Conversely, insituations of iron excess, both serum iron andpercentage saturation are high. Measurement of serum iron is accomplished byFigure 13. Serum ferritin levels according to sex andusing a specific color of reagent to quantitate ironage. (From Hillman, RS, and Finch, CA: Red Cellafter it is freed from transferrin. Transferrin may beManual, ed 7. FA Davis, Philadelphia, 1996, p 64, withmeasured directly through immunoelectrophoretic permission.) 25. Copyright 2003 F.A. Davis Company 12SECTION ILaboratory TestsReference Values Conventional UnitsSI UnitsSerum IronNewborns 350500 mg/dL62.789.5 mmol/LChildren 40200 mg/dL 7.235.8 mmol/LAdultsMen60170 mg/dL 10.730.4 mmol/LWomen50130 mg/dL 9.023.3 mmol/LElderly persons4080 mg/dL7.214.3 mmol/LTransferrinNewborns 60170 mg/dL 0.61.7 g/LAdults 250450 mg/dL2.54.5 g/L% Saturation (of Transferrin)Newborns 65% saturation 0.65Adults 2055% saturation0.200.55TIBCChildren 100350 mg/dL1863 mmol/LAdults 300360 mg/dL5464 mmol/LElderly persons200310 mg/dL3656 mmol/LFerritinChildren 2040 mg/dL2040 mg/LAdultsMen50200 mg/dL 50200 mg/L(average 100 mg/dL)(avg 100 mg/L)Women (menstruating) 12100 mg/dL 12100 mg/L(average 30 mg/dL) (avg 30 mg/L)may be normal if serum iron and transferrin Monitoring hematologic responses during preg-levels are proportionately decreased; if thenancy, when serum iron is usually decreased,problem is solely one of protein homeostasistransferrin levels are increased (in the third(with normal iron stores), percentage satura- trimester), percentage saturation is low, TIBCtion will be high.may be increased, and ferritin may be decreasedSupport for diagnosing hemochromatosis or (Note: Transferrin levels may be increased inother disorders of iron metabolism and storage: women taking oral contraceptives, whereasSerum iron and ferritin levels may be elevatedferritin levels may be decreased in womenin hemochromatosis and hemosiderosis; who are menstruating or who have borne chil-percentage saturation of transferrin is elevated, dren.)whereas TIBC is decreased.NURSING CARE BEFORE THE PROCEDURESerum iron levels can be elevated in leadpoisoning, after multiple blood transfusions, Client preparation is the same as that for any studyand in severe hemolytic disorders that causeinvolving the collection of a peripheral blood samplerelease of iron from damaged RBCs.(see Appendix I). 26. Copyright 2003 F.A. Davis Company CHAPTER 1Hematology and Tests of Hematopoietic Function 13 Reference Values Conventional Units SI UnitsVitamin B12 Serum 200900 pg/mL148664 pmol/LFolic acidSerum 1.89 ng/mL420 nmol/LRBCs95500 ng/mL 2151133 nmol/L Blood for serum iron and TIBC should be drawnvegetable origin such as lima beans, kidney beans, in the morning, in the fasting state, and 24 hours and dark-green leafy vegetables. Note that canning or more after discontinuing iron-containingand prolonged cooking destroy folate. Normally medications.17 functioning intestinal mucosa is necessary forabsorption of both vitamin B12 and folic acid.THE PROCEDURE Vitamin B12 is normally stored in the liver inA venipuncture is performed and the samplesufficient quantity to withstand 1 year of zero intake.collected in a red-topped tube. A capillary sampleIn contrast, most of the folic acid absorbed goesmay be obtained in infants and children as well directly to the tissues, with a smaller amount storedas in adults for whom venipuncture may not be in the liver. Folate stores are adequate for only 2 to 4feasible. months.NURSING CARE AFTER THE PROCEDUREINDICATIONS FOR VITAMIN B12 ANDCare and assessment after the procedure are the FOLIC ACID STUDIESsame as for any study involving the collection of aDetermination of the cause of megaloblasticperipheral blood sample (see Appendix I).anemia:Food, fluids, and medications withheld before Diagnosis of pernicious anemia, a megaloblas-the test may be resumed after the sample is tic anemia characterized by vitamin B12 defi-obtained. ciency despite normal dietary intakeComplications and precautions: Note and report Diagnosis of megaloblastic anemia caused bysigns and symptoms of anemia: decreases in test deficient folic acid intake or increased folatelevels, fatigue and weakness, increased pulse, exer- requirements (e.g., in pregnancy and hemolytictional dyspnea, and dizziness. If anemia is caused anemias) or both, as indicated by decreasedby blood loss, prepare to administer a transfusion serum levels of folic acidof blood products. If anemia is caused by ironMonitoring response to disorders that may lead todeficiency, administer ordered oral or parenteralvitamin B12 deficiency (e.g., gastric surgery, age-(intramuscular) iron supplement and instructrelated atrophy of the gastric mucosa, surgicalclient in dietary inclusion of foods high in ironresection of the ileum, intestinal parasites, over-content. After 4 to 7 days, check iron studies,growth of intestinal bacteria)RBC count, reticulocyte count, and hemoglobinMonitoring response to disorders that may lead tolevels to see whether iron stores have been replen-folate deficiency (e.g., disease of the small intes-ished.tine, sprue, cirrhosis, chronic alcoholism, uremia,some malignancies)18VITAMIN B12 AND FOLIC ACID STUDIESMonitoring effects of drugs that are folic acidantagonists (e.g., alcohol, anticonvulsants, anti-Vitamin B12 (cyanocobalamin) and folic acidmalarials, and certain drugs used to treat(pteroylglutamic acid) are essential for the produc-leukemia)19tion and maturation of erythrocytes. Both must beMonitoring effects of prolonged parenteral nutri-present for normal DNA replication and cell divi-tionsion. In humans, vitamin B12 is obtained only byeating animal proteins, milk, and eggs, which placesNURSING CARE BEFORE THE PROCEDUREstrict vegetarians at risk for developing cobalamindeficiency; hydrochloric acid (HCl) and intrinsic Client preparation is the same as that for any studyfactor are required for absorption. Folic acid (orinvolving the collection of a peripheral blood samplefolate) is present in liver and in many foods of(see Appendix I). 27. Copyright 2003 F.A. Davis Company 14SECTION ILaboratory TestsSamples should be drawn after the client has The difference between men and women resultsfasted for 8 hours and before injections of vitamin partly from menstrual blood loss in women andB12 have been given.partly from the effects of androgens in men.Alcohol also should be avoided for 24 hours Castration of men usually causes hemoglobin andbefore the test.hematocrit to decline to nearly the same levels asthose of women. Note that a decline in erythrocytes THE PROCEDUREis experienced by both genders in old age.21 A venipuncture is performed and the sampleMore detailed discussions of the RBC and WBC collected in a red-topped tube. A capillary sample components of the CBC are included in succeeding may be obtained in infants and children as well as insections of this chapter. Platelets are discussed in adults for whom venipuncture may not be feasible.Chapter 2. NURSING CARE AFTER THE PROCEDUREReference Values Care and assessment after the procedure are the same as for any study involving the collection of a The components of the CBC and their peripheral blood sample (see Appendix I). reference values across the life cycle are shown in Foods and drugs withheld before the test may be Table 14. resumed after the sample is obtained. Complications and precautions (anemia): Note and report folic acid levels of less than 4 ng and aINDICATIONS FOR A COMPLETE BLOOD COUNT normal level of vitamin B12, indicating folic acid anemia. Prepare to administer ordered oral Because the CBC provides much information about replacement therapy of folic acid; dosage andthe overall health of the individual, it is an essential duration depend on the cause of the deficiency.component of a complete physical examination, Perform nursing activities for vitamin B12 defi- especially when performed on admission to a ciency as in pernicious anemia diagnosed by thehealth-care facility or before surgery. Other indica- Schilling test (see Chapter 20). tions for a CBC are as follows: Suspected hematologic disorder, neoplasm, or immunologic abnormality COMPLETE BLOOD COUNT History of hereditary hematologic abnormality A CBC includes (1) enumeration of the cellularSuspected infection (local or systemic, acute or elements of the blood, (2) evaluation of RBCchronic) indices, and (3) determination of cell morphology Monitoring effects of physical or emotional stress by means of stained smears. Counting is performed Monitoring desired responses to drug therapy and by automated electronic devices capable of rapidundesired reactions to drugs that may cause blood analysis of blood samples with a measurement errordyscrasias (Table 15) of less than 2 percent.20 Monitoring progression of nonhematologicReference values for the CBC vary across the lifedisorders such as chronic obstructive pulmonary cycle and between the genders. In the neonate, when disease, malabsorption syndromes, malignancies, oxygen demand is high, the number of erythrocytes and renal disease also is high. As demand decreases, destruction of theNURSING CARE BEFORE THE PROCEDURE excess cells results in decreased erythrocyte, hemo- globin, and hematocrit levels. During childhood, Client preparation is the same as that for any study RBC levels again rise, although hemoglobin levelsinvolving the collection of a peripheral blood sample may decrease slightly. (see Appendix I).In prepubertal children, normal erythrocyte andTHE PROCEDURE hemoglobin levels are the same for boys and girls. During puberty, however, values for boys rise, A venipuncture is performed and the sample whereas values for girls decrease. In men, these collected in a lavender-topped tube. A capillary higher values persist to age 40 or 50, decline slowlysample may be obtained in infants and children, as to age 70, and then decrease rapidly thereafter. Inwell as in adults for whom venipuncture may not be women, the drop in hemoglobin and hematocrit feasible. that begins with puberty reverses at about age 50 butNURSING CARE AFTER THE PROCEDURE never rises to prepubertal levels or to that of men of the same age.Care and assessment after the procedure are the 28. Copyright 2003 F.A. Davis Company TABLE 14 Reference Values for Complete Blood Count AdultCBC Component Newborn 1 Mo 6 Mo110 YrMale FemaleRed blood cells 4.87.1 million/mm34.16.43.85.54.54.84.66.2 4.25.4 million/mm3(RBCs) 12 million/mm3million/mm3million/mm3million/mm34.87.110 /L (SI units)Hematocrit (Hct)4.464%3549% 3040% 3541% 4054%3847%Hemoglobin (Hgb)1424 g/L (SI units) 1120 g/dL 1015 g/dL 1116 g/dL 13.518 g/dL1216 g/dL CHAPTER 1Hematology140240 g/L (SI units) 110200 g/L100150 g/L110160 g/L135180 g/L 120160 g/LRBC indicesMCV*96108 m3829138094 m38199 m396108 fL (SI units) 8291 fL 8094 fL8199 fL MCH 3234 pg 2731 pg 2731 pg MCHC3233% 3236% 3236% and Tests of Hematopoietic Function320330 S/L (SI units) 320360 S/L320360 S/LStained RBC Normochromic and normocytic for all age groups and both sexes (see p. 23)examinationWhite blood cells 9,00030,000/mm3 6,00018,000/mm3 6,00016,000/mm3 5,00013,000/mm35,00010,000/mm3 (WBCs) 99,00030,00010 /L (SIunits) (Continued on following page) 15 29. Copyright 2003 F.A. Davis Company 16 SECTION ILaboratory TABLE 14 Reference Values for Complete Blood Count (Continued)AdultCBC Component Newborn 1 Mo6 Mo 110 Yr MaleFemaleDifferential WBC TestsNeutrophils 45% by 1 wk40% by 4 wk 32%60% after age 2 yr 5475%(30007500/mm3)Bands 38% (150700/mm3)Eosinophils 03% 14% (50400/mm3)Basophils 13% 01% (25100/mm3)Monocytes 49% 28% (100500/mm3)Lymphocytes 41% by 1 wk56% by 4 wk 61%59% after age 2 yr 2540%(15004500/mm3) T lymphocytes 6080% of lympho-cytes B lymphocytes 1020% of lympho-cytes Platelets140,000300,000/mm3150,000390,000/200,000473,000/ 150,000450,000/150,000450,000/mm3 mm3 mm3mm3140300 109/L (SI units) 150390 109/L 200473 109/L150450109/L150450109/L * Mean corpuscular volume. Mean corpuscular hemoglobin. Mean corpuscular hemoglobin concentration. 30. Copyright 2003 F.A. Davis CompanyCHAPTER 1Hematologyand Tests of Hematopoietic Function17TABLE 15 Drugs That May Cause Blood Dyscrasias Generic Name or Class Trade Names Acetaminophen and acetaminophenBancap, Capital, Colrex, Comtrex, Darvocet-N, Datril, Dolene, compoundsDuradrin, Duradyne, Esgic, Excedrin, Liquiprin, Midrin,Neopap Supprettes, NyQuil, Ornex, Panadol, Parafon Forte,Percogesic, Phrenilin, Sedapap, Sinarest, Sinutab, Supac,Tylenol, Tempra, Tylenol with Codeine, Valadol, Vanquish,Wygesic Acetophenazine maleate Tindal Aminosalicylic acidPamisyl, PAS, Rezipas Amphotericin B Fungizone, Mysteclin F Antineoplastic agents Arsenicals CarbamazepineTegretol ChloramphenicolChloromycetin ChloroquineAralen Ethosuximide (methsuximide, phen-Zarontin suximide) Furazolidone Furoxone HaloperidolHaldol Hydantoin derivativesEthotoinPeganoneMephenytoin MesantoinPhenytoin Dilantin, Diphenylan HydralazineApresazide, Apresoline, Bolazine, Ser-Ap-Es, Serpasil-Apresoline Hydroxychloroquine sulfate Plaquenil Indomethacin Indocin IsoniazidINH, Nydrazid, Rifamate MAO inhibitors Eutonyl, Nardil, Parnate Mefenamic acid Ponstel MepacrineAtabrine MephenoxaloneLenetron Mercurial diureticsThiomerin Metaxalone Skelaxin Methaqualone Quaalude, Sopor Methyldopa Aldoclor, Aldomet, Aldoril Nitrites Nitrofurantoin Cyantin, Furadantin, Macrodantin Novobiocin Albamycin Oleandomycin Matromycin (Continued on following page) 31. Copyright 2003 F.A. Davis Company 18 SECTION ILaboratory Tests TABLE 15 Drugs That May Cause Blood Dyscrasias (Continued)Generic Name or Class Trade NamesOxyphenbutazone Oxalid, TandearilParamethadioneParadionePenicillamine Cuprimine, DepenPenicillinsPhenacemide PhenuronePhenobarbitalPhenylbutazoneAzolid, ButazolidinPhytonadioneAquaMEPHYTON, KonakionPrimaquinePrimidone MysolinePyrazolone derivativesButazolidin, Tandearil, OxalidPyrimethamine DaraprimRifampinRifadin, Rifamate, RimactaneRadioisotopesSpectinomycin TrobicinSulfonamidesMafenideSulfamylon creamPhthalylsulfathiazole SulfathalidineSulfabenzamideSultrin vaginal creamSulfacetamide Bleph-10, Cetamide ointment, Isopto Cetamide, Sulamyd, Sultrinvaginal creamSulfachloropyridazine SonilynSulfacytine RenoquidSulfadiazineSilvadeneSulfameterSullaSulfamethiozole Thiosulfil ForteSulfamethoxazoleAzo Gantanol, Bactrim, Gantanol, SeptraSulfamethoxypyridazineMidicelSulfanilamide AVC vaginal creamSulfasalazine AzulfidineSulfathiazole Sultrin vaginal cream, Triple Sulfa creamSulfinpyrazoneAnturaneSulfisoxazole Azo Gantrisin, GantrisinSulfonesDapsoneDDSSulfoxone 32. Copyright 2003 F.A. Davis CompanyCHAPTER 1Hematology and Tests of Hematopoietic Function19 TABLE 15 Drugs That May Cause Blood Dyscrasias Generic Name or ClassTrade NamesSulfonylureasAcetohexamideDymelorChlorpropamide DiabineseTolazamide TolinaseTolbutamideOrinaseTetracyclinesAchromycinChlortetracyclineAureomycinDemeclocycline DeclomycinDoxycyclineDoxychel, Doxy, Vibramycin, Vibra-TabsMeclocycline MeclanMethacycline RondomycinMinocyclineMinocinOxytetracyclineOxlopar, TerramycinThiazide diuretics (rare hematologic Ademol, Diuril, Enduron, Exna, Naturetin, Naqua, Renese,side effects) SaluronThiocyanatesTrimethadioneTridioneTripelennamine Pyribenzamine, PBZTroleandomycin Cyclamycin, Tao capsules and suspensionValproic acidValproateVitamin AAquasol A, Alphalinsame as for any study involving the collection of a oxygen from the lungs to all body cells and transferperipheral blood sample (see Appendix I). carbon dioxide from the cells to the organs of excre-Abnormal range of values: Note and report tion. The RBC is resilient and capable of extremedecreases in individual or entire CBC (pancytope- changes in shape. It is admirably designed to survivenia) panel. Prepare to administer drugs and treat-its many trips through the circulation.22ments, or both, that have been ordered to manage Old, damaged, and abnormal erythrocytes areanemia (RBC, hematocrit [Hct], hemoglobin removed mainly by the spleen and also by the liver[Hgb], RBC indices), clotting process (platelet), and the red bone marrow. The iron is returned toor infectious process (WBC, differential).plasma transferrin and is transported back to theerythroid marrow or stored within the liver andspleen as ferritin and hemosiderin. The bilirubinERYTHROCYTE STUDIEScomponent of Hgb is carried by plasma albumin toThe mature RBC (erythrocyte) is a biconcave diskthe liver, where it is conjugated and excreted into thewith an average life span of 120 days. Because it lacks bile. Most of this conjugated bilirubin is ultimatelya nucleus and mitochondria, it is unable to synthe- excreted in the stool, although some appears in thesize protein, and its limited metabolism is barelyurine or is returned to bile.enough to sustain it. Erythrocytes function prima- The hematologist determines the numbers, struc-rily as containers for Hgb. As such, they transport ture, color, size, and shape of erythrocytes; the types 33. Copyright 2003 F.A. Davis Company 20 SECTION ILaboratory Tests and amount of Hgb they contain; their fragility; and INDICATIONS FOR AN ERYTHROCYTE (RBC) any abnormal components.COUNTRoutine screening as part of a CBC ERYTHROCYTE (RBC) COUNTSuspected hematologic disorder involving RBCdestruction (e.g., hemolytic anemia) The erythrocyte (RBC) count, a component of theMonitoring effects of acute or chronic blood loss CBC, is the determination of the number of RBCsMonitoring response to drug therapy that may per cubic millimeter. In international units, this isalter the RBC count (see Table 15) expressed as the number of RBCs per liter of blood.Monitoring clients with disorders associated with The test is less significant by itself than it is in elevated RBC counts (e.g., polycythemia vera, computing Hgb, Hct, and RBC indices. chronic obstructive pulmonary disease)Many factors influence the level of circulating Monitoring clients with disorders associated with erythrocytes. Decreased numbers are seen in disor- decreased RBC counts (e.g., malabsorption ders involving impaired erythropoiesis excessive syndromes, malnutrition, liver disease, renal blood cell destruction (e.g., hemolytic anemia), and disease, hypothyroidism, adrenal dysfunction, blood loss, and in chronic inflammatory diseases. Abone marrow failure) relative decrease also may be seen in situations with increased body fluid in the presence of a normal NURSING CARE BEFORE THE PROCEDURE number of RBCs (e.g., pregnancy). Increases in the Client preparation is the same as that for any study RBC count are most commonly seen in poly-involving the collection of a peripheral blood sample cythemia vera, chronic pulmonary disease with(see Appendix I). hypoxia and secondary polycythemia, and dehydra- tion with hemoconcentration. Excessive exercise, THE PROCEDURE anxiety, and pain also produce higher RBC counts.A venipuncture is performed and the sample Many drugs can cause a decrease in circulating RBCscollected in a lavender-topped tube. A capillary (see Table 15), whereas a few drugs, such as methyl-sample may be obtained in infants and children as dopa and gentamicin, can cause an increase.23well as in adults for whom venipuncture may not befeasible. INTERFERING FACTORSNURSING CARE AFTER THE PROCEDUREExcessive exercise, anxiety, pain, and dehydrationmay lead to false elevations. Care and assessment after the procedure are theHemodilution in the presence of a normalsame as for any study involving the collection of anumber of RBCs may lead to false decreases (e.g., peripheral blood sample (see Appendix I).excessive administration of intravenous fluids, Anemia: Note and report signs and symptoms ofnormal pregnancy).anemia associated with decreased counts inMany drugs may cause a decrease in circulatingcombination with Hgb and Hct decreases. PrepareRBCs (see Table 15). to administer ordered oral or parenteral ironDrugs such as methyldopa and gentamicin may preparation or a transfusion of whole blood orcause an elevated RBC count.packed RBCs. Prepare for phlebotomy if levels areReference Values Conventional UnitsSI Units3Newborns 4.87.1 million/mm4.87.11012/L1 mo 4.16.4 million/mm3 4.16.41012/L6 mo 3.85.5 million/mm3 3.85.51012/L110 yr4.54.8 million/mm3 4.54.81012/LAdultsMen4.66.2 million/mm3 4.66.21012/LWomen4.25.4 million/mm3 4.25.41012/L 34. Copyright 2003 F.A. Davis CompanyCHAPTER 1Hematology and Tests of Hematopoietic Function21 increased in polycythemia vera or secondary poly-INTERFERING FACTORS cythemia.Abnormalities in RBC size and extremely elevatedWBC counts may alter Hct values.HEMATOCRITElevated blood glucose and sodium may produceelevated Hct values because of swelling of theBlood consists of a fluid portion (plasma) and aerythrocyte.solid portion that includes RBCs, WBCs, andFactors that alter the RBC count such as hemodi-platelets. More than 99 percent of the total blood celllution and dehydration also influence the Hct.mass is composed of RBCs. The Hct or packed RBCvolume measures the proportion of RBCs in a INDICATIONS FOR A HEMATOCRIT TESTvolume of whole blood and is expressed as aRoutine screening as part of a CBCpercentage.Along with an Hgb (i.e., an H and H), to moni- Several methods can be used to perform the test.tor blood loss and response to blood replacementIn the classic method, anticoagulated venous bloodAlong with an Hgb, to evaluate known oris pipetted into a tube 100 mm long and thensuspected anemia and related treatmentcentrifuged for 30 minutes so that the plasma andAlong with an Hgb, to monitor hematologicblood cells separate. The volumes of packed RBCsstatus during pregnancyand plasma are read directly from the millimeterMonitoring responses to fluid imbalances or tomarks along the side of the tube. In the microtherapy for fluid imbalances:method, venous or capillary blood is used to fill a A decreased Hct may indicate hemodilution.small capillary tube, which is then centrifuged for 4 An increased Hct may indicate dehydration.to 5 minutes. The proportions of plasma and RBCsare determined by means of a calibrated reading NURSING CARE BEFORE THE PROCEDUREdevice. Both techniques allow visual estimation ofthe volume of WBCs and platelets.24 Client preparation is the same as that for any study With the newer, automated methods of cellinvolving the collection of a peripheral blood samplecounting, the Hct is calculated indirectly as the (see Appendix I).product of the RBC count and mean cell volume.THE PROCEDUREAlthough this method is generally quite accurate,certain clinical situations may cause errors in inter-The volume of the sample needed depends on thepreting the Hct. Abnormalities in RBC size andmethod used to determine the Hct. With the excep-extremely elevated WBC counts may produce false tion of the classic method of Hct determination, aHct values. Elevated blood glucose and sodium may capillary sample is usually sufficient to perform theproduce elevated Hct values because of the resultanttest. If a venipuncture is performed, the sample isswelling of the erythrocyte.25collected in a lavender-topped tube. Normally, the Hct parallels the RBC count. Thus, NURSING CARE AFTER THE PROCEDUREfactors influencing the RBC count also affect theresults of the Hct. Care and assessment after the procedure are thesame as for any study involving the collection of aperipheral blood sample (see Appendix I).Reference ValuesCritical values: Notify the physician at once ifConventional Units SI Units the Hct is greater than 60 percent or less than14 percent. Prepare the client for possible Newborns4464%0.4464transfusion of blood products or infusion of 1 mo3549%0.350.49intravenous fluids and for further proceduresto evaluate the cause or source of the blood 6 mo3040%0.300.40loss or hemoconcentration. 110 yr 3541%0.350.41 AdultsHEMOGLOBINMen4054%0.400.54Hemoglobin is the main intracellular protein of theWomen3847%0.380.47RBC. Its primary function is to transport oxygen to Critical values 14% or60%0.14 0.60the cells and to remove carbon dioxide from themfor excretion by the lungs. The Hgb molecule Note: Values vary across the life cycle and between genders.consists of two main components: heme and globin. 35. Copyright 2003 F.A. Davis Company 22SECTION ILaboratory Tests Heme is composed of the red pigment porphyrinReference Values and iron, which is capable of combining loosely with oxygen. Globin is a protein that consists of nearlyConventional Units SI Units 600 amino acids organized into four polypeptideNewborns 1424 g/dL 140240 g/L chains. Each chain of globin is associated with a heme group.1 mo 1120 g/dL 110200 g/LEach RBC contains approximately 250 million 6 mo 1015 g/dL 100150 g/L molecules of hemoglobin, with some erythro- cytes containing more hemoglobin than others.110 yr1116 g/dL 110160 g/L The oxygen-binding, -carrying, and -releasingAdults capacity of Hgb depends on the ability of the globin chains to shift position normally during the Men13.518 g/dL135180 g/L oxygenationdeoxygenation process. Structurally Women 1216 g/dL 120160 g/L abnormal chains that are unable to shift normally have decreased oxygen-carrying ability. This Critical values 6.0 g/dL 60 g/L decreased oxygen transport capacity is characteristic200 g/dL 200 g/L of anemia. Note: Ratio of hemoglobin to hematocrit 3:1.Hemoglobin also functions as a buffer in the maintenance of acidbase balance. During trans- port, carbon dioxide (CO2) reacts with water (H2O) ate known or suspected anemia and related treat- to form carbonic acid (H2CO3). This reaction isment speeded by carbonic anhydrase, an enzyme Along with an Hct, to monitor blood loss and contained in RBCs. The carbonic acid rapidly disso-response to blood replacement ciates to form hydrogen ions (H ) and bicarbonateAlong with an Hct, to monitor hematologic status ions (HCO3). The hydrogen ions combine with the during pregnancy Hgb molecule, thus preventing a buildup of hydro-NURSING CARE BEFORE THE PROCEDURE gen ions in the blood. The bicarbonate ions diffuse into the plasma and play a role in the bicarbonate Client preparation is the same as that for any study buffer system. As bicarbonate ions enter the blood-involving the collection of a peripheral blood sample stream, chloride ions (Cl ) are repelled and move(see Appendix I). back into the erythrocyte. This chloride shiftTHE PROCEDURE maintains the electrical balance between RBCs and plasma.26A venipuncture is performed and the sampleHemoglobin determinations are of greatest use incollected in a lavender-topped tube. A capillary the evaluation of anemia, because the oxygen-carry-sample may be obtained in infants and children as ing capacity of the blood is directly related to the well as in adults for whom venipuncture may not be Hgb level rather than to the number of erythrocytes. feasible. To interpret results accurately, the Hgb level must beNURSING CARE AFTER THE PROCEDURE determined in combination with the Hct level. Normally, Hgb and Hct levels parallel each other and Care and assessment after the procedure are the are commonly used together to express the degree ofsame as for any study involving the collection of a anemia. The combined values are also useful in eval- peripheral blood sample (see Appendix I). uating situations involving blood loss and related Critical values: Notify the physician at once if treatment. The Hct level is normally three times the the Hgb is less than 6.0 g/dL. Prepare the client Hgb level. If erythrocytes are abnormal in shape orfor possible transfusion of blood products and size or if Hgb manufacture is defective, the relation- for further procedures to evaluate cause or ship between Hgb and Hct is disproportionate.27,28 source of blood loss. INTERFERING FACTORSRED BLOOD CELL INDICES Factors that alter the RBC count may also influence Hgb levels RBC indices are calculated mean values that reflectthe size, weight, and Hgb content of individual INDICATIONS FOR HEMOGLOBIN DETERMINATIONerythrocytes. They consist of the mean corpuscularRoutine screening as part of a CBCvolume (MCV), the mean corpuscular hemoglobinAlong with an Hct (i.e., an H and H), to evalu- (MCH), and the mean corpuscular hemoglobin 36. Copyright 2003 F.A. Davis Company CHAPTER 1Hematologyand Tests of Hematopoietic Function 23 TABLE 16 Classification of AnemiasMCV* MCHMCHCAnemia Examples of Causes(mm3) (pg) (%) Normocytic, normochromicSepsis, hemorrhage, hemolysis, 829225303236 drug-induced aplastic anemia, radiation, hereditary spherocytosis Microcytic, normochromicRenal disease, infection, liver80 202527 disease, malignancies Microcytic, hypochromic Iron deficiency, lead poisoning, 508012252530thalassemia, rheumatoid arthritis Macrocytic,normochromic Vitamin B12 and folic acid deficiency,some drugs, pernicious anemia 95150 30503236* Mean corpuscular volume. Mean corpuscular hemoglobin. Mean corpuscular hemoglobin concentration.concentration (MCHC). MCV indicates the volumeanemias classified according to these terms and inof the Hgb in each RBC, MCH is the weight of therelation to the results of RBC indices.Hgb in each RBC, and MCHC is the proportion of To calculate the RBC indices, the results of anHgb contained in each RBC. MCHC is a valuable RBC count, Hct, and Hgb are necessary. Thus,indicator of Hgb deficiency and of the oxygen-carry-factors that influence these three determinationsing capacity of the individual erythrocyte. A cell of (e.g., abnormalities of RBC size or extremelyabnormal size, abnormal shape, or both may containelevated WBC counts) may result in misleading RBCan inadequate proportion of Hgb.indices. For this reason, a stained blood smear may RBC indices are used mainly in identifying be used to compare appearance with calculatedand classifying types of anemias. Anemias are values and to determine the etiology of identifiedgenerally classified according to RBC size and Hgbabnormalities.content. Cell size is indicated by the terms normo-INTERFERING FACTORScytic, microcytic, and macrocytic. Hemoglobincontent is indicated by the terms normochromic, Because RBC indices are calculated from the resultshypochromic, and hyperchromic. Table 16 showsof the RBC count, Hgb, and Hct, factors that influ- Reference Values MenWomen Newborns SI Units 333MCV8094 m8199 m96108 m8199 fL (women) 96108 fL (newborns)MCH2731 pg 2731 pg 3234 pg3234 pg (women) 3234 pg (newborns)MCHC 3236% 3236% 3233% 320360 g/L (women)320330 g/L (newborns) Normal values for RBC indices are shown in Table 14 in relation to the CBC and also are repeated above for adults. Values in newborn infants are slightly different, but adult levels are achieved within approximately 1 month of age. 37. Copyright 2003 F.A. Davis Company 24SECTION ILaboratory Tests ence the latter three tests (e.g., abnormalities of RBC STAINED RED BLOOD CELL size, extremely elevated WBC counts) also influence EXAMINATION RBC indices. The stained RBC examination (RBC morphology) INDICATIONS FOR RED BLOOD CELL INDICES involves examination of RBCs under a microscope.Routine screening as part of a CBC It is usually performed to compare the actualIdentification and classification of anemias (seeappearance of the cells with the calculated valuesTable 16) for RBC indices. Cells are examined for abnormali- ties in color, size, shape, and contents. The test is NURSING CARE BEFORE THE PROCEDURE performed by spreading a drop of fresh anticoagu- Client preparation is the same as that for any studylated blood on a glass slide. The addition of stain involving the collection of a peripheral blood sample to the specimen is used to enhance RBC characteris- (see Appendix I). tics.As with RBC indices, RBC color is described as THE PROCEDURE normochromic, hypochromic, or hyperchromic, A venipuncture is performed and the sampleindicating, respectively, normal, reduced, or elevated collected in a lavender-topped tube. A capillaryamounts of Hgb. Cell size may be described as sample may be obtained in infants and children as normocytic, microcytic, or macrocytic, depending well as in adults for whom venipuncture may not beon whether cell size is normal, small, or abnormally feasible. large, respectively. Cell shape is described using terms such as poikilocyte, anisocyte, leptocyte, and NURSING CARE AFTER THE PROCEDURE spherocyte (Table 17). The cells are examined also Care and assessment after the procedure are the for inclusions or abnormal cell contents, for exam- same as for any study involving the collection of a ple, Heinz bodies, Howell-Jolly bodies, Cabots rings, peripheral blood sample (see Appendix I). and siderotic granules (Table 18).TABLE 17 Red Blood Cell Abnormalities Seen on Stained Smear Descriptive Term Observation SignificanceMacrocytosisCell diameter8 mMegaloblastic anemiasMCV* 95 m3Severe liver diseaseHypothyroidismMicrocytosisCell diameter6 mIron-deficiency anemia 3MCV 80 mThalassemiasMCHC27 Anemia of chronic diseaseHypochromia Increased zone of central pallorDiminished Hgb contentHyperchromiaMicrocytic, hyperchromic cellsChronic inflammationIncreased bone marrow stores of Defect in ability to use iron for Hgb synthesisironPolychromatophiliaPresence of red cells not fully ReticulocytosishemoglobinizedPoikilocytosisVariability of cell shape Sickle cell diseaseMicroangiopathic hemolysisLeukemiasExtramedullary hematopoiesisMarrow stress of any cause 38. Copyright 2003 F.A. Davis Company CHAPTER 1Hematology and Tests of Hematopoietic Function25 TABLE 17 Red Blood Cell Abnormalities Seen on Stained SmearDescriptive TermObservationSignificance AnisocytosisVariability of cell sizeReticulocytosis Transfusing normal blood into microcytic or macrocytic cell population LeptocytosisHypochromic cells with smallThalassemias central zone of Hgb (target cells) Obstructive jaundice Spherocytosis Cells with no central pallor, Loss of membrane relative to cell volume loss of biconcave shape Hereditary spherocytosis SchistocytosisMCHC high Accelerated red blood cell destruction by reticuloendothelial system AcanthocytosisPresence of cell fragments in Increased intravascular mechanical trauma circulation Microangiopathic hemolysis Echinocytosis Irregularly spiculated surfaceIrreversibly abnormal membranelipid content Liver disease Abetalipoproteinemia Regularly spiculated cell surface Reversible abnormalities of membrane lipids High plasma-free fatty acids Bile acid abnormalities Effects of barbiturates, salicylates, and so on StomatocytosisElongated, slitlike zone of central Hereditary defect in membrane sodium pallormetabolism Severe liver disease ElliptocytosisOval cellsHereditary anomaly, usually harmlessSource: Adapted from Sacher, RA, and McPherson, RA: Widmanns Clinical Interpretation of Laboratory Tests,ed 11. FA Davis, Philadelphia, 2000 p. 68, with permission.* Mean corpuscular volume.Mean corpuscular hemoglobin concentration.Reference Values Evaluation of anemia and related disorders involving RBCs (see Tables 16, 17, and 18)In a normal smear, all cells are uniform in color,size, and shape and are free of abnormal NURSING CARE BEFORE THE PROCEDUREcontents. A normal RBC may be described as a Client preparation is the same as that for any studynormochromic, normocytic cell. involving the collection of a peripheral blood sample (see Appendix I).INDICATIONS FOR A STAINED RED BLOOD CELL THE PROCEDUREEXAMINATION A venipuncture is performed and the sample Abnormal calculated values for RBC indicescollected in a lavender-topped tube. A capillary 39. Copyright 2003 F.A. Davis Company 26SECTION ILaboratoryTests TABLE 18 Types of Abnormal Red Blood Cell Inclusions and Their Causes Type (Composition) Causes of InclusionsHeinz bodies (denatured Hgb) -Thalassemia G-6-PD deficiency Hemolytic anemias Methemoglobinemia Splenectomy Drugs: analgesics, antimalarials, antipyretics, nitrofurantoin (Furadantin), nitrofurazone (Furacin), phenylhydrazine, sulfonamides, tolbutamide, vitamin K (large doses)Basophilic stippling (residual Anemia caused by liver diseasecytoplasmic RNA) Lead poisoning ThalassemiaHowell-Jolly bodies (frag- Splenectomy ments of residual DNA)Intense or abnormal RBC production resulting from hemolysis or ineffi- cient erythropoiesisCabots rings (composition Same as for Howell-Jolly bodiesunknown)Siderotic granules (iron-Abnormal iron metabolismcontaining granules) Abnormal hemoglobin manufacture sample may be obtained in infants and children as At birth, most RBCs contain fetal hemoglobin well as in adults for whom venipuncture may not be (Hgb F), which is made up of two chains and two feasible. chains. Within a few months, through sequentialsuppression and activation of individual genes, Hgb NURSING CARE AFTER THE PROCEDUREF largely disappears and is replaced by adult hemo- Care and assessment after the procedure are theglobin (Hgb A). Hgb A, composed of two chains same as for any study involving the collection of aand two chains, makes up more than 95 percent of peripheral blood sample (see Appendix I).Hgb in adults. A minor type of Hgb, Hgb A2, consist-ing of two chains and two chains, also is found HEMOGLOBIN ELECTROPHORESIS in small amounts (2 to 3 percent) in adults. Traces ofHgb F persist throughout life (Fig. 14).29 The Hgb molecule consists of four polypeptide More than 150 genetic abnormalities in the Hgb globin chains and four heme components contain-molecule have been identified. These are termed ing iron and the red pigment porphyrin.thalassemias and hemoglobinopathies. Thalassemias Hemoglobin formation is genetically determined,are genetic disorders in globin chain synthesis that and the types of globin chains normally formed are result in decreased production rates of - or - termed alpha ( ), beta ( ), gamma ( ), and delta globin chains. Hemoglobinopathies refer to disor- ( ). Combinations of these chains form various ders involving an abnormal amino acid sequence in types of Hgb. Disorders of synthesis and productionthe globin chains. of globin chains result in the formation of abnormalIn -thalassemia, for example, production of Hgb. chains and Hgb A is decreased. The oversupply ofHemoglobin electrophoresis is a technique for chains results in the formation of hemoglobin H identifying the types of Hgb present and for deter-(Hgb H), which consists of four chains (Fig. 15). mining the percentage of each type. Exposed to anComplete absence of a chain production (homozy- electrical current, the several types of Hgb migrate gous thalassemia A) is incompatible with life and toward the positive pole at different rates. The generally results in stillbirth during the second patterns created are compared with standardtrimester of pregnancy. The cord blood of such patterns.fetuses shows high levels of hemoglobin Barts, a type 40. Copyright 2003 F.A. Davis Company CHAPTER 1Hematology and Tests of Hematopoietic Function 27 The Sickledex test, a screening test for sickle cell disorders, detects sickled erythrocytes under condi- tions of oxygen deprivation. Hemoglobin elec- trophoresis is necessary, however, to differentiate sickle cell trait (20 to 40 percent Hgb S) from sickle cell disease (70 percent Hgb S).Many other types of abnormal Hgb are caused by defects in globin chain synthesis. Hemoglobin C (Hgb C), for example, has an abnormal amino acid substitution on the chain and can lead to a form of mild hemolytic anemia. Other examples of abnor- mal Hgb resulting from rearrangement or substitu- tion of the amino acids on the globin chains include hemoglobin E (Hgb E), hemoglobin Lepore ( - chain abnormalities), and hemoglobin Constant Spring ( -chain abnormality).30Other disorders involving Hgb pertain to the oxygen-combining ability of the heme portion of the molecule. Examples of types of Hgb associated with such disorders are methemoglobin (Hgb M), sulfhemoglobin, and carboxyhemoglobin. Hgb M is formed when the iron contained in the heme portion of the Hgb molecule is oxidized to a ferric instead of a ferrous form, thus impairing its oxygen- combining ability. Methemoglobinemia may be Figure 14. Changes in hemoglobin with develop- hereditary or acquired. The acquired form may be ment. (From Hillman, RS, and Finch, CA: Red Cellcaused by excessive radiation or by the toxic effects Manual, ed 7. FA Davis, Philadelphia, 1996, p. 11, with of chemicals and drugs (e.g., nitrates, phenacetin, permission.) lidocaine). Note that Hgb F is more easily converted to Hgb M than is Hgb A.of Hgb that evolves from unpaired chains. Sulfhemoglobin is a pigment that results fromHemoglobin Barts itself has such a high affinity for Hgb combining with inorganic sulfides. It occurs inoxygen that it releases none to the tissues. those who take sulfonamides or acetanilid. In -thalassemia minor, a decrease is seen in - Carboxyhemoglobin results when Hgb is exposedchain production and, therefore, a reduction in theto carbon monoxide. Although this type of Hgb isamount of Hgb A formed. In -thalassemia major, most commonly seen in individuals with excessiveall -chain production is lost and no Hgb A isexposure to automobile exhaust fumes, it may alsoformed. The chains are then used to form Hgb F occur in heavy smokers.31 Tests other than Hgb elec-and Hgb A2.trophoresis are used to determine the presence of Among the most common Hgb abnormalities are Hgb M and carboxyhemoglobin.the sickle cell disorders, which exhibit a double INDICATIONS FOR HEMOGLOBINgene defect that results in the production of hemo- ELECTROPHORESISglobin S (Hgb S). In Hgb S, the amino acid valine issubstituted for glutamine at a critical position on theSuspected thalassemia, especially in individualsglobin chain, which causes the chains to lockwith positive family history for the disorderwhen deoxygenated, deforming the erythrocyte intoDifferentiation among the types of thalassemiasthe sickled shape. Repeated sickling damages RBC Evaluation of a positive Sickledex test to differen-membranes and shortens the cells life spans. Thetiate sickle cell trait (20 to 40 percent Hgb S) fromabnormally shaped cells pass more sluggishly sickle cell disease (70 percent Hgb S)through the circulation, leading to impaired tissueEvaluation of hemolytic anemia of unknownoxygenation. etiology The gene for Hgb S is most prevalent in black Diagnosis of Hgb C anemiapopulations and may be present as either sickle cell Identification of the numerous types of abnormaltrait (having one recessive gene for Hgb S) or sickleHgb, most of which do not produce clinicalcell disease (having both recessive genes for Hgb S).disease 41. Copyright 2003 F.A. Davis Company 28SECTION ILaboratory Tests Figure 15. Formation of manual and abnormal hemoglobin. (From Hillman, RS, and Finch, CA: Red Cell Manual, ed 7. FA Davis, Philadelphia, 1996, with permission.)Reference ValuesThe normal values shown for Hgb electrophoresis are for adults. Innewborn infants, 60 to 90 percent of Hgb may consist of Hgb F. Thisamount decreases to 10 to 20 percent by 6 months of age and to 2 to4 percent by 1 year. Abnormal forms of Hgb (e.g., Hgb S, Hgb H) arenot normally present.Conventional UnitsSI UnitsHgb A9597%0.95Hgb A2 23%0.020.03Hgb F 1% 0.01Methemoglobin (Hgb M) 2% or 0.060.24 g/dLSulfhemoglobin Minute amountsCarboxyhemoglobin02.3% 45% in smokers 42. Copyright 2003 F.A. Davis Company CHAPTER 1Hematology and Tests of Hematopoietic Function 29NURSING CARE BEFORE THE PROCEDUREThe test is performed by exposing RBCs toincreasingly dilute saline solutions. The percentageClient preparation is the same as that for any studyof the solution at which the cells swell and rupture isinvolving the collection of a peripheral blood samplethen noted.(see Appendix I).THE PROCEDURE Reference ValuesA venipuncture is performed and the sample Normal erythrocytes rupture in saline solutionscollected in a lavender-topped tube. A capillary of 0.30 to 0.45 percent. RBC rupture in solutionssample may be obtained in infants and children asof greater than 0.50 percent saline indicateswell as in adults for whom venipuncture may not be increased fragility. Lack of rupture in solutionsfeasible.of less than 0.30 percent saline indicatesNURSING CARE AFTER THE PROCEDURE decreased RBC fragility.Care and assessment after the procedure are thesame as for any study involving the collection of aINDICATIONS FOR OSMOTIC FRAGILITY TESTperipheral blood sample (see Appendix I).Complications and precautions: Note and report Confirmation of disorders that alter RBC fragility,signs and symptoms associated with the specificincluding hereditary anemias (see Table 19)type of anemia identified by electrophoresis.Evaluation of the extent of extrinsic damage toPrepare to instruct in therapy and prevention of RBCs from burns, inadvertent instillation ofcomplications. Offer information about genetic hypotonic intravenous fluids, microorganisms,factors and counseling or both, if appropriate.and excessive exerciseNURSING CARE BEFORE THE PROCEDUREOSMOTIC FRAGILITYClient preparation is the same as that for any studyThe osmotic fragility test determines the ability ofinvolving the collection of a peripheral blood samplethe RCB membrane to resist rupturing in a hypo- (see Appendix I).tonic saline solution. Normal disk-shaped cells canTHE PROCEDUREimbibe water and swell significantly beforemembrane capacity is exceeded, but spherocytesA venipuncture is performed and the sample(RBCs that lack the normal biconcave shape) and collected in a green-topped tube. A capillary samplecells with damaged membranes burst in saline solu-may be obtained in infants and children as well as intions only slightly less concentrated than normal adults for whom a venipuncture may not be feasible.saline. Conversely, in thalassemia, sickle cell disease,NURSING CARE AFTER THE PROCEDUREand other disorders, RBCs are more than normallyresistant to osmotic damage (Table 19).Care and assessment after the procedure are the TABLE 19 Causes of Altered Erythrocyte Osmotic FragilityDecreased FragilityIncreased Fragility Iron-deficiency anemias Hereditary spherocytosis Hereditary anemias (sickle cell, hemoglobin C,Hemolytic anemias thalassemias) Liver diseasesAutoimmune anemias Polycythemia vera Burns Splenectomy Toxins (bacterial, chemical) Obstructive jaundiceHypotonic infusions Transfusion with incompatible blood Mechanical trauma to RBCs (prosthetic heart valves,disseminated intravascular clotting, parasites) Enzyme deficiencies (PK kinase, G-6-PD) 43. Copyright 2003 F.A. Davis Company 30SECTION ILaboratory Tests same as for any study involving the collection of a probenecid [Benemid], quinidine, quinine, sulfon- peripheral blood sample (see Appendix I). amides, thiazide diuretics, and tolbutamide Abnormal test results, complications, and [Orinase]). precautions: Respond as for any laboratory analy-A Mediterranean variant also may occur, espe- sis to determine RBC abnormalities leading to cially in individuals of Greek and Italian descent and anemia. in some small, inbred Jewish populations. This vari- ant severely reduces enzymatic activity and leads to more severe hemolytic episodes, which are triggered RED BLOOD CELL ENZYMES by a greater variety of stimuli and are less likely to be To maintain normal shape and flexibility as well as self-limited than in persons with the type A variant. to combine with and release oxygen, RBCs must In addition to the oxidative stressors just listed, generate energy. The needed energy is producedingestion of fava beans is known to precipitate almost exclusively through the breakdown of hemolytic events in individuals with Mediterranean- glucose, a process that is catalyzed by a number of type G-6-PD deficiency.32 enzymes. Deficiencies of these enzymes are associ- PYRUVATE KINASE ated with hemolytic anemia. Two of the most common deficiencies, both hereditary, involve the Pyruvate kinase (PK) functions in the formation of RBC enzymes glucose-6-phosphate dehydrogenase pyruvate and adenosine diphosphate (ADP) in and pyruvate kinase.glycolysis. The pyruvate thus formed is subsequently converted to lactate. RBCs that lack PK have a low GLUCOSE-6-PHOSPHATE DEHYDROGENASE affinity for oxygen. Episodes of hemolysis in individ- Glucose-6-phosphate dehydrogenase is an enzymeuals lacking this enzyme are severe and chronic and pivotal in generating the reduced form of nicoti- are exacerbated by stressors such as infection. namide adenine dinucleotide phosphate (NADPH)The inherited form of this disorder is transmitted through the pentose pathway in glucose metabolism.as an autosomal recessive trait; both parents must More than 100 structural and functional variants of carry the abnormal gene for the child to be affected. the normal G-6-PD molecule (called type B) have The acquired form of PK deficiency is usually caused been identified, most of which are clinically insignif- by either drug ingestion or metabolic liver disease. icant. One variant form (called type A) does, INTERFERING FACTORS however, produce clinical disease. The type A variant is caused by a sex-linked genetic defect. The abnor-Young RBCs have higher enzyme levels than do mal gene is carried by women and is transmitted toolder ones; thus, if the tests are performed within 10 men who inherit the disorder. days of a hemolytic episode (when the body isPersons with the type A