Ebook A Manual of laboratory and diagnostic tests (9th edition): Part 1

(BQ) Part 1 book A Manual of laboratory and diagnostic tests presents the following contents: Diagnostic testing, blood studies - hematology and coagulation, urine studies, stool studies, cerebrospinal fluid studies, chemistry studies, chemistry studies.

Frontmatter Title A MANUAL i OF Laboratory and Diagnostic Tests NINTH EDITION Fischbach_FM_printer_file.indd i 11/4/13 10:43 PM Fischbach_FM_printer_file.indd ii 11/4/13 10:43 PM A MANUAL OF Laboratory and Diagnostic Tests NINTH EDITION Frances Talaska Fischbach, RN, BSN, MSN Associate Clinical Professor of Nursing 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 Professor of Medicine & Physiology Department of Medicine Division of Pulmonary/Critical Care Medicine Medical College of Wisconsin Milwaukee, Wisconsin Fischbach_FM_printer_file.indd iii 11/4/13 10:43 PM Acquisitions Editor: Patrick Barbera Managing Editor: Roxanne Halpine Ward Design Coordinator: Holly McLaughlin Art Director, Illustration: Jennifer Clements Production Project Manager: Cynthia Rudy Manufacturing Coordinator: Karin Duffield Prepress Vendor: Absolute Service, Inc 9th Edition Copyright © 2015 Wolters Kluwer Health | Lippincott Williams & Wilkins Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Copyright © 2004, 2000 by Lippincott Williams & Wilkins Copyright © 1996 by Lippincott-Raven Publishers Copyright © 1992, 1988, 1984, 1980 by J B Lippincott Company All rights reserved This book is protected by copyright No part of this book may be reproduced or transmitted in any form or by any means, including as photocopies or scanned-in or other electronic copies, or utilized by any information storage and retrieval system without written permission from the copyright owner, except for brief quotations embodied in critical articles and reviews Materials appearing in this book prepared by individuals as part of their official duties as U.S government employees are not covered by the above-mentioned copyright To request permission, please contact Lippincott Williams & Wilkins at Two Commerce Square, 2001 Market Street, Philadelphia, PA 19103, via email at permissions@lww.com, or via our website at lww.com (products and services) 987654321 Printed in China Library of Congress Cataloging-in-Publication Data ISBN: 978-1-4511-9089-2 Cataloging-in-Publication Data available on request from the publisher Care has been taken to confirm the accuracy of the information presented and to describe generally accepted practices However, the authors, editors, and publisher are not responsible for errors or omissions or for any consequences from application of the information in this book and make no warranty, expressed or implied, with respect to the currency, completeness, or accuracy of the contents of the publication Application of this information in a particular situation remains the professional responsibility of the practitioner; the clinical treatments described and recommended may not be considered absolute and universal recommendations The authors, editors, and publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accordance with the current recommendations and practice at the time of publication However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any change in indications and dosage and for added warnings and precautions This is particularly important when the recommended agent is a new or infrequently employed drug Some drugs and medical devices presented in this publication have Food and Drug Administration (FDA) clearance for limited use in restricted research settings It is the responsibility of the health care provider to ascertain the FDA status of each drug or device planned for use in his or her clinical practice LWW.COM Fischbach_FM_printer_file.indd iv 11/4/13 10:43 PM To the memory of Marshall B Dunning III Dear friend and coauthor 1947–2013 Fischbach_FM_printer_file.indd v 11/4/13 10:43 PM Contributors, Consultants, and Research Assistants Margaret A Fischbach, RN, BA, JD Compliance Officer Allay Home & Hospice, Inc Brookfield, Wisconsin Mary Fischbach Johnson, BA, MS Research Assistant New York, New York Patricia A Van Kampen Student Nurse Research Assistant Wausau, Wisconsin Patti Cobb, RD, CD Chief Clinical Dietitian Food and Nutrition Services Froedtert Hospital Milwaukee, Wisconsin Carol Colasacco, CT(ASCP), CMIAC Cytotechnologist, Department of Pathology Fletcher Allen Health Care Burlington, Vermont Faye Enriquez, RN, BSN, MSN Associate Clinical Professor School of Nursing University of Wisconsin Milwaukee, Wisconsin Ann Shafranski Fischbach, RN, CAOHC, CPID Case Manager Restore Wheaton Franciscan Health Care Milwaukee, Wisconsin Gary Hoffman Manager, Laboratory for Newborn Screening State of Wisconsin Madison, Wisconsin Paul J Jannetto, PhD, MT(ASCP), DABCC Associate Professor, Pathology Director, Clinical Chemistry/Toxicology Medical College of Wisconsin Milwaukee, Wisconsin Jennifer Johnson RN, BSN Cardiothoracic Procurement Coordinator Loyola University Medical Center Maywood, Illinois Karen Kehl, PhD Associate Professor-Pathology Children’s Hospital of Wisconsin Milwaukee, Wisconsin Stanley F Lo, PhD, DABCC, FACB Associate Professor, Pathology Associate Director, Clinical Laboratories Technical Director, Clinical Chemistry, Point of Care, and Biochemical Genetics Directory, Reference Standards Laboratory Children’s Hospital of Wisconsin Medical College of Wisconsin Milwaukee, Wisconsin Charles R Myers, PhD Professor of Pharmacology and Toxicology Medical College of Wisconsin Milwaukee, Wisconsin Christine Naczek, MT(ASCP) Manager, Blood Banking and Pre-Transfusion Testing Department of Pathology United Regional Medical Services, Inc Milwaukee, Wisconsin Anne Witkowiak Nezworski, RN, BSN Maternity and Newborn Specialist Marshfield Clinic, Eau Claire Center Eau Claire, Wisconsin vi Fischbach_FM_printer_file.indd vi 11/4/13 10:43 PM Contributors, Consultants, and Research Assistants Joseph Nezworski, ES, RN, BSN Chief Deputy Medical Examiner Eau Claire County Nursing Supervisor Sacred Heart Hospital Eau Claire, Wisconsin Rochelle Olive-Harmon, MS RT (R) Program Director School of Radiologic Technology Froedtert Hospital Medical College of Wisconsin Milwaukee, Wisconsin Hershel Raff, PhD Department of Endocrinology Medical College of Wisconsin St Luke’s Medical Center Milwaukee, Wisconsin Tracy A Schweitzer, PhD, RN, BSN, MA Clinical Assistant Professor Marquette University Milwaukee, Wisconsin John Shalkham, MA, SCT(ASCP) Program Director for School of Cytotechnology State Laboratory of Hygiene Clinical Assistant Professor Department of Pathology University of Wisconsin Madison, Wisconsin Jean M Trione, RPh Clinical Specialist Wausau Hospital Wausau, Wisconsin Patti Wilson BSN, RN, CIC Infection Control Coordinator Froedtert Hospital Milwaukee, Wisconsin Michael Zacharisen, MD Professor of Pediatrics Children’s Hospital of Wisconsin Milwaukee, Wisconsin Reviewers Sheryl F Banak, MSN, RN, CNE Faculty RN Program Baptist Health Schools Little Rock Little Rock, Arkansas Simone Bollaerts, BN, RN, IIWCC Professor in Nursing Mohawk College of Applied Arts and Technology Hamilton, Ontario, Canada Susan Weber Buchholz, PhD, RN Professor Rush University College of Nursing Chicago, Illinois Frank G Steffel, BS, CNMT Program Director–Nuclear Medicine/PET Technology Froedtert Hospital Milwaukee, Wisconsin Susan K Callen, MSN, RN, CNE Nursing Instructor II UPMC Shadyside School of Nursing Pittsburgh, Pennsylvania Corrinne Strandell, RN, BSN, MSN, PhD Nursing Research, Home Care and Rehabilitation Specialist West Allis, Wisconsin Sandi Casey MS, RNC-MNN Nursing Instructor Connors State College Muskogee, Oklahoma Thudung Tieu, MT(ASCP) Quality Assurance & Safety Manager Dynacare Laboratories Milwaukee, Wisconsin Karen Chandra, MSN, MBA, RN Associate Professor of Nursing Harper College Palatine, Illinois Fischbach_FM_printer_file.indd vii vii 11/4/13 10:43 PM viii Reviewers Christine M Cunningham, MS, MT (ASCP) Associate Professor New York Chiropractic College Seneca Falls, New York Pasquale Fiore, RN, BScN, MSc, Health Adm, Cert Ed Nurse Educator Camosun College University of Victoria Victoria, British Columbia, Canada Paula Green, MSN Assistant Professor Nursing & Allied Sciences Bronx Community College - CUNY Bronx, New York Nancy E Pea, MSN, RN Associate Professor St Louis Community College Ferguson, Missouri Carswella Phillips, DNP, MSN, ARNP Assistant Professor Florida Agricultural and Mechanical University, School of Nursing Tallahassee, Florida Vanessa Pomarico-Denino, MSN, APRN, FNP-BC Interim Director and Lead Faculty Family Nurse Practitioner Track Southern Connecticut State University New Haven, Connecticut Cathy R Kessenich, DSN, ARNP, FAANP Professor of Nursing University of Tampa Tampa, Florida Charlene Strumpel, MSN, RN Instructor University of British Columbia, Okanagan Campus Kelowna, British Columbia, Canada Julie A Koch, DNP, RN, FNP-BC Assistant Professor and Coordinator of the FNP Program Valparaiso University College of Nursing Valparaiso, Indiana Angela Trott, MSN-Ed, BSN, RN Associate Degree Nursing Instructor Coastal Carolina Community College Jacksonville, North Carolina Diane M Lew-Snide, PhD, RN Professor of Nursing Columbia-Greene Community College Hudson, New York Catherine Mbewe, MS, RN Assistant Professor Nursing and Allied Health Sciences Bronx Community College - CUNY Bronx, New York S Wendy Whillans, MScN, RN Faculty, School of Nursing Canadore College North Bay, Ontario, Canada Mary Ellen Wilkosz, PhD, MSN, BSN, RN, FNP-BC Associate Professor and Assistant Director FNP Program Sonoma State University Rohnert Park, California Janet O’Connell, MA Ed, BN Professor of Nursing Ryerson University, Centennial College, George Brown College Collaborative BScN Program Toronto, Ontario, Canada Fischbach_FM_printer_file.indd viii 11/4/13 10:43 PM 534 CHAPTER ● Stool and Anal Cultures and Smears Place the specimen in biohazard bag; not refrigerate Immediately transport the specimen to the laboratory for bacterial, fungal, or viral cultures CLINICAL ALERT The most useful and common specimens for detection of fungal infection are skin scrapings, nail scrapings, and hairs Clinical Implications When present on the skin in significant quantities, the following organisms may be considered pathogenic and indicative of an abnormal condition: Enterobacteriaceae Fungi (Sporotrichum, Actinomyces, Nocardia, C albicans, Trichophyton, Microsporum, Epidermophyton) Staphylococcus aureus Streptococcus pyogenes P aeruginosa Varicella-zoster virus Herpes simplex virus Interventions Pretest Patient Care Explain purpose and skin culture procedure Follow Chapter guidelines for safe, effective, informed pretest care Posttest Patient Care Interpret test outcomes, monitor site of infection, and counsel appropriately about treatment Report rashes, fever, and so forth Follow Chapter guidelines for safe, effective, informed posttest care ● Stool and Anal Cultures and Smears Stool cultures are commonly done to identify bacteria associated with enteric infection Of all specimens collected, feces are likely to contain the greatest number and greatest variety of organisms For a routine stool culture, the stool is examined to detect and to rule out Salmonella, Shigella, Campylobacter, Aeromonas, Plesiomonas, and predominating numbers of Staphylococcus organisms; cultures for yeast, Pseudomonas, Yersinia, Vibrio, and Shiga toxin–producing E coli have to be specifically requested, depending on laboratory practice Clostridium difficile causes antibiotic-associated colitis It is diagnosed by detection of the toxins A single negative stool culture should not be considered the end point in testing At least three stool cultures collected on separate days are recommended if the patient’s clinical picture suggests bacterial involvement, despite previous negative cultures Moreover, once a positive diagnosis has been made, the patient’s personal contacts should also be tested to prevent a potential spread of infection Reference Values Normal The following organisms may be present in the stool of apparently healthy people: C albicans Enterococcus spp Fischbach_Ch07_printer_file.indd 534 11/4/13 10:22 PM ● Stool and Anal Cultures and Smears 535 E coli Proteus spp Pseudomonas aeruginosa Streptococcus spp Staphylococcus spp Procedure Procedure for stool specimen collection a Observe standard precautions b Use a dry container or a clean, dry bedpan to collect feces Do not contaminate stool specimen with urine, soap, or disinfectants c Remember that a freshly passed stool is best Diarrheal stool usually gives acceptable results d Select portions containing pus, blood, or mucus; to grams is sufficient e Do not retrieve stool from the toilet for specimen use f Do not place toilet tissue or diapers with the specimen Either may contain bismuth, which interferes with laboratory tests g Transfer stool specimens from the bedpan to the container with tongue blades h Properly label the sealed specimen container and immediately send it to the laboratory i Place the specimen in a transport medium, such as Cary-Blair medium, if a delay of longer than hours for stool culture is anticipated (from time of collection until receipt in the laboratory) Specimens processed within hours of collection not require added preservatives Place the designated volume of stool into the transport container Procedure for obtaining a rectal swab a Observe standard precautions b Insert the swab gently into the rectum (to a depth of at least cm) and rotate it to retrieve a visible amount of fecal material (Fig 7.2) c Place the swab into the receptacle containing transport medium, such as Cary-Blair medium d Properly label the specimen and send it in a biohazard bag to the laboratory as soon as possible e Rectal swab may not contain sufficient sample to detect enteric pathogens Whenever possible, stool should be submitted FIGURE 7.2 Method for obtaining the rectal culture Fischbach_Ch07_printer_file.indd 535 11/4/13 10:22 PM 536 CHAPTER ● Stool and Anal Cultures and Smears CLINICAL ALERT Fecal specimens are far superior to rectal swab specimens Often, rectal swabs reach only the anal canal and provide material of limited diagnostic significance Procedure for performing cellophane tape test for pinworm (Enterobius vermicularis) a Observe standard precautions The tape test is indicated in cases of suspected enterobiasis (pinworms) b Apply a strip of clear cellophane tape (not micropore or adhesive-type tape) to the perineal region Remove and spread the tape on a slide for microscopic examination c Remember that a paraffin-coated swab can be used in place of the cellophane tape test If used, place the swab within a stoppered test tube d Be aware that it may be necessary to make four to six examinations on consecutive days before ruling out the presence of pinworms e Test for pinworm eggs in the morning, before the patient has defecated or bathed For small children, it is best to collect the specimen just before the child awakens Clinical Implications C albicans, S aureus, and P aeruginosa, found in large numbers in the stool, are considered pathogenic in the setting of previous antibiotic therapy Alterations of normal flora by antibiotics often change the environment so that normally harmless organisms become pathogens Cryptosporidiosis is a cause of severe, protracted diarrhea in immunosuppressed patients Cryptosporidium organisms can be detected by ova and parasite examination H pylori has been associated with gastritis and peptic ulcer disease H pylori is found only on the mucus-secreting epithelial cells of the stomach Detection of H pylori in gastric biopsy specimens necessitates collection of the specimens in sterile containers Smears and cultures should be examined for the presence of this organism Initial culture incubation requires days Therefore, results of gastric biopsy specimen cultures may take to 10 days to obtain A test for H pylori antigen in the stool provides rapid detection of H pylori C difficile: Whenever normal flora are reduced by antibiotic therapy or other host factors, the syndrome known as pseudomembranous colitis can occur This condition is caused by C difficile It may be present in small numbers in the normal person, or it may occur in the hospital environment When normal flora are reduced, C difficile can multiply and produce its toxins The definitive diagnosis of C difficile–associated diarrhea is based on clinical criteria Endoscopic visualization of a characteristic pseudomembrane or plaque, together with a history of antibiotic therapy, is diagnostic of C difficile Three laboratory tests are also available These include stool culture for C difficile (nonspecific; requires at least 48 hours); tissue culture for detection of cytotoxin (48 hours); and rapid antigen tests for toxins that are sensitive and specific for C difficile Interfering Factors Feces from patients receiving barium, bismuth, mineral oil, or antibiotics are not satisfactory specimens for identifying protozoa Interventions Pretest Patient Care Explain purpose and procedure Obtain history of diarrhea, including type and length of time Instruct the patient to defecate into a clean, dry bedpan or large-mouthed container Fischbach_Ch07_printer_file.indd 536 11/4/13 10:22 PM ● Cerebrospinal Fluid (CSF) Cultures and Smears 537 Do not allow patient to defecate into the toilet bowl or urinate into the bedpan or collecting container because urine has an adverse effect on protozoa Do not place toilet paper into the bedpan or collection container; it may contain bismuth, which can interfere with testing Follow Chapter guidelines for safe, effective, informed pretest care Posttest Patient Care Interpret test outcomes, monitor for intestinal infection, and counsel appropriately about treatment and possible further testing Report signs and symptoms Follow Chapter guidelines for safe, effective, informed posttest care CLINICAL ALERT In the institutional setting, patients with diarrhea should remain in isolation until the cause for the diarrhea is determined When pathogens are found in the diarrheic stool, the patient usually remains isolated until the stool becomes formed and antibiotic therapy is completed ● Cerebrospinal Fluid (CSF) Cultures and Smears Bacteriologic examination of CSF is an essential step in the diagnosis of any case of suspected meningitis Acute bacterial meningitis is an infection of the meninges (the membrane covering the brain and spinal cord) It is a rapidly progressive, fatal infection if left untreated or if treated inadequately Death can occur within hours of symptom onset Prompt identification of the causative agent is necessary for appropriate antibiotic therapy and aggressive treatment Meningitis is caused by a variety of gram-positive and gramnegative microorganisms Bacterial meningitis also can be secondary to infections in other areas of the body A smear and culture should be performed on all CSF specimens obtained from persons with suspected meningitis, whether the CSF fluid appears clear (normal) or cloudy In bacterial meningitis (except TB meningitis), the CSF shows the following characteristics: Purulence (usually) Increased numbers of leukocytes Preponderance of polymorphonuclear cells Decreased CSF glucose concentration in relation to serum glucose Elevated CSF protein concentration In meningitis caused by the tubercle bacillus, viruses, fungi, or protozoa, the CSF shows the following characteristics: Nonpurulent (usually) Decreased mononuclear white cell count; increased lymphocytes Normal or decreased CSF glucose concentration Elevated CSF protein concentration In those persons with suspected meningitis, the CSF fluid is generally submitted for chemical and cytologic examinations as well as culture Indications for Collection Viral meningitis Pyogenic meningitis Fischbach_Ch07_printer_file.indd 537 11/4/13 10:22 PM 538 CHAPTER ● Cerebrospinal Fluid (CSF) Cultures and Smears TB meningitis Chronic meningitis Reference Values Normal Negative: No growth Bacteria are not normally present in CSF However, the specimen may be contaminated by normal skin flora during the process of CSF procurement Procedure Collect the specimen under sterile conditions Three or four tubes (1.0 mL per tube) of CSF should be collected The third tube is used for cell count and differential; the others can be used for microbiologic and chemical studies Seal immediately to prevent leakage or contamination, and send it to the laboratory without delay CLINICAL ALERT In cases of suspected meningitis, a culture should be done and a diagnosis made as quickly as possible This is important because some causative organisms cannot tolerate temperature changes If a viral cause is suspected, a portion of the CSF fluid should be refrigerated (0° to 4°C) Freezing is not recommended unless inoculation into tissue culture will take longer than days If PCR testing is to be performed, specimens may need to be frozen immediately Label the specimen properly Alert laboratory staff so that the specimen can be examined immediately Notify the attending physician as soon as results are obtained so that appropriate treatment can be started in a timely fashion CLINICAL ALERT Newborns have the highest prevalence of meningitis of any age group Organisms causing infection in the newborn (usually acquired during the birth process) include group B streptococcus, E coli, and L monocytogenes CLINICAL ALERT CSF findings may not differentiate between bacterial and viral meningitis Generally, however, white blood cell counts of 1,000 to 10,000 cells/␮L are associated with a bacterial cause, whereas counts from Ͻ100 to 1,000 cells/␮L are associated with an underlying viral origin Clinical Implications Pathogens found in CSF include: a Cryptococcus and other fungi b H influenzae Fischbach_Ch07_printer_file.indd 538 11/4/13 10:22 PM ● Cervical, Urethral, Anal, and Oropharyngeal Cultures and Smears for STIs 539 c Naegleria or Acanthamoeba spp d Viruses (usually enteroviruses) or herpes simplex virus e L monocytogenes f M tuberculosis g N meningitidis h Streptococcus pneumoniae i Staphylococcus aureus j Staphylococcus epidermidis k Streptococcus (group B) l Treponema pallidum m Toxoplasma gondii Positive CSF cultures occur in: a Meningitis b Trauma c Abscess of brain or ependyma of spine d Septic thrombophlebitis of venous sinuses Maintenance of Culture If the CSF specimen cannot be delivered to the laboratory immediately, the container should be stored at room temperature No more than hours should elapse before laboratory analysis takes place because of the low survival rates of the organisms causing meningitis (especially H influenzae and N meningitidis) Interventions Pretest Patient Care Explain purpose and lumbar puncture procedure (see Chapter 5) Record pertinent signs and symptoms Follow Chapter guidelines for safe, effective, informed pretest care Posttest Patient Care Interpret test outcomes, monitor for meningitis, and counsel appropriately (see Chapter 5) Follow Chapter guidelines for safe, effective, informed posttest care ● Cervical, Urethral, Anal, and Oropharyngeal Cultures and Smears for Gonorrhea and Other Sexually Transmitted Infections These tests are done for patients with genital ulcers, vaginal lymphadenopathy, bacterial vaginosis (pathogens such as Gardnerella, Bacteroides, Prevotella, and Mobiluncus), lesions affecting epithelial surfaces, signs and symptoms of bacterial STIs, pelvic inflammatory disease, urethritis, or abnormal discharge and itching Reference Values Normal Negative: Normal flora; negative for pathogenic antigens Procedures for Specimens Cervical (female patients) a Be aware that the cervix is the best site from which to obtain a culture specimen b Observe standard precautions c Moisten the vaginal speculum with warm water; not use a lubricant Remove cervical mucus, preferably with a cotton ball held in a ring forceps Fischbach_Ch07_printer_file.indd 539 11/4/13 10:22 PM 540 CHAPTER ● Cervical, Urethral, Anal, and Oropharyngeal Cultures and Smears for STIs FIGURE 7.3 Method for obtaining the endocervical specimen d Insert a sterile, cotton-tipped swab into the endocervical canal; move the swab from side to side; allow 30 seconds for absorption of organisms by the swab (Fig 7.3) Vagina (female patients) a A vaginal fluid sample is collected on a swab by contacting the lower one third of the vaginal wall The swab is placed for 10 minutes in a test vessel to which a developer solution has been added The solution will turn blue or green if positive (OSOM BVBLUE Test, Genzyme Corporation, Cambridge, MA) b Using an immunographic assay, a vaginal fluid sample is obtained by a swab that is subsequently placed in a test tube to which a sample buffer has been added The results are read after 10 minutes (OSOM Trichomonas Rapid Test, Genzyme Corporation, Cambridge, MA) Urethral (male patients) a Use a sterile swab to obtain the specimen from the anterior urethra by gently scraping the urethral mucosa (Fig 7.4) b Rotate the swab 360° to dislodge some of the epithelial cells for Chlamydia N gonorrhoeae organisms inhabit the exudate, whereas C trachomatis organisms are intracellular (within the epithelial cells) Anal canal a Insert a sterile, cotton-tipped swab approximately 2.5 cm into the anal canal (If the swab is inadvertently pushed into feces, use another swab to obtain the specimen.) b Move the swab from side to side in the anal canal to sample the crypts; allow several seconds for absorption of organisms by the swab c Remember that this site is likely to be positive in a patient with STI, when a cervical specimen is negative Fischbach_Ch07_printer_file.indd 540 11/4/13 10:22 PM ● Cervical, Urethral, Anal, and Oropharyngeal Cultures and Smears for STIs 541 FIGURE 7.4 Method for obtaining the urethral specimen Because Trichomonas vaginalis may be present in urethral or vaginal discharge, material for culture should be collected as described; however, an additional swab should be placed in a tube containing 0.5 mL of sterile saline and be delivered to the laboratory immediately Swabs for culture should be transported to the laboratory in Stuart’s transport medium and should be held at room temperature until processed If specimens are not processed within 12 hours, they should be refrigerated Recovery of a pathologic organism may be more difficult because of delay in processing PROCEDURAL ALERT If the male urethral culture is negative but gonorrhea is still suspected, prostatic massage may produce an increased number of organisms in the urethral discharge The first morning specimen before urination may be the best In a female patient, the anal canal specimen can be obtained after the cervical specimen without changing the patient’s position and without using the anoscope Observe standard precautions Interventions Pretest Patient Care Explain culture purpose and collection procedure Obtain history of pertinent signs and symptoms (drainage, pain, itching) Place the patient in the dorsal lithotomy position and appropriately drape for genital procedures Provide as much privacy as possible Follow standard precautions Follow Chapter guidelines for safe, effective, informed pretest care Posttest Patient Care Interpret test outcomes and counsel appropriately Explain need for possible follow-up testing and treatment The use of pre-exposure vaccines (e.g., hepatitis A and B [frequently sexually transmitted] and human papillomavirus) is the most effective means of preventing STIs Follow Chapter guidelines for safe, effective, informed posttest care CLINICAL ALERT The finding of repeated negative cultures for gonococci does not always exclude a diagnosis of gonorrhea Fischbach_Ch07_printer_file.indd 541 11/4/13 10:22 PM 542 CHAPTER ● Tissue, Bone, and Body Fluid Cultures ● Tissue, Bone, and Body Fluid Cultures Types of fluid collected for bacterial, viral, or fungal culture include pleural, ascitic, synovial, and pericardial fluid Tissues may have to be minced or ground to release trapped bacteria before culturing Reference Values Normal Negative for pathogens Procedure for Collection of Specimens Transport body fluids to the laboratory in a sterile tube or sterile-capped syringe Ten to 20 mL of fluid is adequate for culture examination Collect bone during surgery and send to the laboratory in a sterile container Place fragments directly onto the agar surface or into enrichment broth Collect pieces of tissue during surgery or during needle biopsy procedures They should be collected in a sterile specimen cup Add a small amount of sterile, nonbacteriostatic saline to keep specimen moist Interventions Pretest Patient Care Explain the purpose and procedure for the culture Follow Chapter guidelines for safe, effective, informed pretest care Posttest Patient Care Interpret test outcomes, monitor site of collection, and counsel appropriately Follow Chapter guidelines for safe, effective, informed posttest care SKIN TESTS Skin testing is done for three major reasons: (1) to detect sensitivity to allergens such as dust and pollen, (2) to determine sensitivity to microorganisms believed to cause infection, and (3) to determine whether cell-mediated immune functions are normal The test that detects sensitivity to allergens is mentioned only briefly in this chapter below; most of this discussion focuses on skin tests used to determine sensitivity to pathogens Reference Values Normal Negative reactions indicate lack of exposure to a specific infection (e.g., TB-producing agent) or sensitivity to a specific allergen (e.g., mold) Intradermal Tests The substance being tested is injected into the layers of skin with a tuberculin syringe fitted with a short-bevel, 26- or 27-gauge needle A positive reaction produces a red, inflamed area at the site of the injection within a given time period (e.g., 72 hours for the Mantoux test for TB) Skin tests that indicate hypersensitivity to a toxin from an infection-producing agent may also signal immunity to the infectious agent Positive reactions may also indicate an active or inactive phase of the infection under study Skin tests can be categorized according to their nature and purpose as follows: Tests to reveal a present or past exposure to the infectious agent, for example, tuberculin test (positive reaction indicates presence of active or inactive TB) Fischbach_Ch07_printer_file.indd 542 11/4/13 10:22 PM ● Tuberculin Skin Test (TB Test); Two-Step TB Test 543 Tests to show sensitivity to materials toward which a person may react in an exaggerated manner; for example, allergenic extracts such as house dust and pollen (positive reaction indicates sensitivity to allergen extracts) Tests to detect impaired cellular immunity Intradermal skin testing with several common antigenic microbial substances (e.g., purified protein derivative [PPD] tuberculin, mumps virus, C albicans, streptokinase-streptodornase) can determine whether immune function is normal This would be important in treating leukemia and cancer with chemotherapy (Negative reaction to any intradermal antigen indicates impaired immunity.) Procedure for Skin Tests Follow the manufacturer’s instructions for the diagnostic skin tests Most are prepackaged as sterile kits Inject 0.1 mL of the test material intradermally on the volar aspect of the forearm Remember that a positive reaction is manifested by redness or swelling Ͼ1 cm in diameter at the injection site A central area of necrosis is a highly significant finding CLINICAL ALERT Material for diagnostic skin tests may be inadvertently injected into subcutaneous tissue rather than intradermal tissue A subcutaneous injection yields a false-negative result See individual skin tests for pretest and posttest interventions ● Tuberculin Skin Test (TB Test); Two-Step TB Test The intradermal tuberculin skin test detects TB infection; it does not distinguish active TB from dormant TB PPD tuberculin is a protein fraction of the tubercle bacilli; when it is introduced into the skin of a person with active or dormant TB infection, it causes a localized skin erythema and induration at the injection site because of accumulated small, sensitized lymphocytes The Mantoux test is the test of choice The tuberculin is injected into the intradermal skin layer with a syringe and fine-gauge needle The multiple puncture test (tine test) is used for screening purposes for asymptomatic persons, but the Mantoux test is far more accurate The two-step TB skin test is done to reduce the likelihood that a “boosted” reaction will be interpreted as a recent infection The two-step skin test is not routine for contact case investigation Indications for Testing Persons who exhibit signs (x-ray film abnormality) or symptoms (e.g., cough, hemoptysis, weight loss) suggestive of TB Recent close contacts with persons known to have or suspected of having TB Persons who show abnormal chest radiographs compatible with past TB exposure Members of groups at high risk for M tuberculosis infection, such as immigrants from Asia, Africa, and Latin America; poverty-prone and “skid row” populations; personnel and long-term residents of health care facilities and institutions (e.g., nursing homes, mental institutions, prisons) The two-step test is indicated for new employees and new residents of institutions (e.g., nursing homes, hospitals, homeless shelters, correctional institutions, alcohol and drug treatment centers), persons 55 years of age and older, and persons born in countries with high prevalence Fischbach_Ch07_printer_file.indd 543 11/4/13 10:22 PM 544 CHAPTER ● Tuberculin Skin Test (TB Test); Two-Step TB Test Reference Values Normal Reaction negative or not significant Procedure for Intradermal Skin Test (Mantoux) Observe standard precautions Draw up PPD tuberculin into a tuberculin syringe (follow manufacturer’s directions carefully) with a 0.5-inch, 26- or 27-gauge needle Use 0.1 mL (5 tuberculin units) for each test Cleanse the skin on the volar or dorsal aspect of the forearm with alcohol and allow it to dry Stretch the skin taut Hold the tuberculin syringe close to the skin so that the hub of the needle touches the skin as the needle is introduced under the skin A discrete, pale elevation of the skin (wheal) to 10 mm in diameter should be produced when the prescribed amount of PPD tuberculin is injected into the intradermal skin layer For the two-step test, administer the Mantoux intradermal skin test, as described, for all persons for whom testing is indicated Strictly enforce reading of results in 48 to 72 hours If the result is positive, not administer a second PPD dose but refer the patient for follow-up If induration is present but does not classify as positive, retest immediately on the patient’s other arm and read the results in 48 to 72 hours If the result of the first Mantoux test is negative, retest in to weeks, using the same PPD dose and the same arm as for the first test Read the results in 48 to 72 hours If the reaction at second test is negative (no induration), perform no further testing now Make plans to administer the one-step Mantoux test yearly (or every to months if the patient is at high risk) Document site of test for follow-up reading of results Clinical Implications The test should be read 48 to 72 hours after injection The larger the area of the skin reaction, the more likely it is to represent TB infection Positive tests show an indurated area of to 15 mm However, a significant reaction to the skin test does not necessarily signify the presence of TB A significant reaction does not distinguish between active and dormant TB infection; the stage of infection can be determined from the results of clinical bacteriologic sputum tests and chest roentgenograms A significant reaction in a clinically ill patient means that active TB should be considered as a cause for illness With HIV infection, a reaction of mm or more is considered positive A significant reaction in a healthy person usually signifies either healed TB or an infection caused by a different mycobacterium Chest roentgenograms can confirm the absence of an active infectious process Interfering Factors False-negative results may occur even in the presence of active TB or whenever sensitized T lymphocytes are temporarily depleted in the body Reading the Test Results The test should be read 48 to 72 hours after injection Examine the injection site in good light The patient should flex the forearm at the elbow Inspect the skin for induration (hardening or thickening) Rub finger lightly from the normal skin area to the indurated zone (if present) Circle the zone of induration with a pencil and measure the diameter in millimeters perpendicularly to the long axis of the forearm Disregard erythema; it is clinically insignificant Large reactions may still be evident days after the test Fischbach_Ch07_printer_file.indd 544 11/4/13 10:22 PM ● Tuberculin Skin Test (TB Test); Two-Step TB Test 545 CLINICAL ALERT Tuberculin test material should never be transferred from one container to another Intradermal skin tests should be given immediately after the tuberculin is drawn up The greatest value of tuberculin skin testing is in the negative results; a negative test result in the presence of signs and symptoms of lung infection is strong evidence against active TB in most cases A presumptive diagnosis of TB must be bacteriologically confirmed In the United States, the incidence of TB is higher among older persons, men, nonwhites, and foreign-born persons Sixteen percent of TB cases are extrapulmonary TB is acquired through close, frequent, and prolonged exposure to infected persons A person diagnosed with TB has on average nine contacts, of whom 21% are infected Persons who have received bacillus Calmette-Guérin (BCG) vaccine prophylactically or for bladder cancer treatment test positive for TB Reactions of to 10 mm may be caused by BCG vaccination However, unless the vaccination was very recent, tuberculin reactions greater than 10 mm should not be attributed to BCG 10 Periodic chest x-ray films are valuable adjuncts for monitoring patients who test positive because there is no sure way of predicting who will develop active TB 11 BCG is a freeze-dried preparation of a live, attenuated bovine strain of mycobacteria It is used for TB immunization in children (e.g., infant with a negative TB test who lives in a household with untreated or ineffectively treated cases of TB) in countries with a high incidence of TB 12 Clinicians in contact with suspected or confirmed TB must wear a properly fitted, high-efficiency, dust- and mist-proof mask Interpreting the Test Results The test interpretation is based on the presence or absence of induration Negative or insignificant reaction: zone of induration Ͻ5 mm in diameter; positive or significant reaction: zone of induration Ͼ10 mm in diameter For persons in good health with no risk factors, an induration of 15 to 20 mm usually is considered positive However, because those who are at increased risk for TB (in poor health) have decreased hypersensitivity, a 5-mm induration may be considered positive Retest within weeks See Chart 7.3 for classification of test results Potential Causes of False-Negative Results Reactions can be categorized according to the following factors: Factors related to person being tested a Presence of infections b Viral (measles, mumps, chickenpox) c Live virus vaccinations (measles, mumps, polio) d Nutritional factors (severe protein depletion) e Diseases affecting lymphoid organs (Hodgkin’s disease, lymphoma, chronic lymphocytic leukemia, sarcoidosis) f Drugs (corticosteroids, other immunosuppressive agents) g Age (newborns, elderly patients with “waned” sensitivity) h Recent or overwhelming M tuberculosis infection Factors related to tuberculin injected a Improper storage (exposure to light, heat) b Improper dilution c Chemical denaturation Fischbach_Ch07_printer_file.indd 545 11/4/13 10:22 PM 546 CHAPTER ● Tuberculin Skin Test (TB Test); Two-Step TB Test CHART 7.3 Classification of the Tuberculin Skin Test Reaction An induration of or more millimeters is considered positive for: • • • • HIV-infected persons Close contacts of a person with infectious TB Persons who have abnormal chest radiographs Persons who inject drugs and whose HIV status is unknown An induration of 10 or more millimeters is considered positive for: • • • • • • • Foreign-born persons HIV-negative persons who inject drugs Medically underserved, low-income populations Residents of long-term care facilities Persons with certain medical conditions* Children Ͻ4 years old without any other risk factors Staff of long-term care facilities and health care facilities An induration of 15 or more millimeters is considered positive for: • Persons who not have any risk factors for TB *For example, diabetes mellitus, prolonged corticosteroid therapy, immunosuppressive therapy, gastrectomy, some hematologic and reticuloendothelial diseases, end-stage renal disease, silicosis, and body weight that is 10% or more below ideal From Centers of Disease Control and Prevention (CDC), Tuberculosis Training and Education Resource Guide, 2003 d Contamination e Absorption (partially controlled by adding Tween-80) f Outdated material Factors related to method of administration a Injection of too little or too much antigen b Delayed administration after drawing up dose c Injection too deep or too shallow Factors related to test interpretation and recording of results a Test not read within prescribed time frame b Inexperienced reader c Conscious or unconscious bias d Recording error e Measurement error Interventions Pretest Patient Care Explain TB skin test purpose and procedure and the necessity of returning for “reading” of the skin reaction Obtain history of occupation, living conditions, and reason for testing Follow Chapter guidelines for safe, effective, informed pretest care Posttest Patient Care Interpret test outcomes at the prescribed time; monitor and counsel appropriately about need for chest radiograph and sputum cultures for those with positive TB skin tests Discuss initial and continued therapy and institute infection and case control as required The  possibility of TB infection must be ruled out before preventive therapy can start TB is a reportable infection Follow Chapter guidelines for safe, effective, informed posttest care Fischbach_Ch07_printer_file.indd 546 11/4/13 10:22 PM ● Mumps Test 547 ● Mumps Test Mumps, the common disease that produces swelling and tenderness of the parotid glands, is caused by a myxovirus An antigen made from infected monkeys or chickens is injected intradermally A positive mumps skin test may indicate either a previous infection or an existing infection; therefore, it is not very effective as a diagnostic tool The test is used primarily as part of a battery of skin tests to determine immunocompetence Reference Values Normal Reaction negative or not significant Procedure Observe standard precautions Before injecting antigen, assess for allergy to eggs Persons who are allergic to eggs are at risk for an anaphylactic reaction to mumps antigen Inject mumps antigen intradermally Clinical Implications A positive reaction indicates resistance to the mumps virus A negative reaction indicates susceptibility to mumps virus Interpretation of the Test Results Read the test 48 hours after the time of injection Positive reaction: erythema and a lesion Ͼ10 mm in diameter Negative reaction: no erythema and a lesion Ͻ10 mm in diameter Interventions Pretest Patient Care Explain skin test purpose and procedure Follow Chapter guidelines for safe, effective, informed pretest care CLINICAL ALERT The following are the ACIP recommendations for mumps vaccination: the first dose of the measles, mumps, rubella (MMR) vaccine should be given at ages 12 to 15 months, followed by a second dose at ages to years The ACIP also recommends two doses of MMR for students attending college and other post–high school institutions Unvaccinated health care workers born before 1957 should have one dose of a live mumps virus vaccine, whereas health care workers born after 1957 should have two doses (minimum interval of 28 days between doses) Posttest Patient Care Interpret test outcomes regarding immunocompetence Follow Chapter guidelines for safe, effective, informed posttest care ● Candida and Tetanus Toxoid Tests Candida and tetanus toxoid are additional skin tests that can be done to detect delayed-type hypersensitivity The Candida antigen is a mixture of trichophytin and Oidium Both antigens are administered in a manner similar to the tuberculin skin test Fischbach_Ch07_printer_file.indd 547 11/4/13 10:22 PM 548 CHAPTER ● Candida and Tetanus Toxoid Tests To interpret these skin tests for anergy, the following CDC guidelines are recommended: For high-risk patients (HIV infection, intravenous drug abuse, immunocompromise), an induration area Ͼ5 mm is considered positive For patients at moderate risk (institutionalized patients, health care workers), an indurated area Ͼ10 mm is significant In patients with no significant risk factors, an indurated area of 15 mm or larger is considered positive These additional skin tests are helpful in evaluating a negative PPD test in an immunosuppressed person No reaction to mumps, tetanus, or Candida testing may indicate a false-negative PPD test However, an induration Ͼ2 mm with the mumps, Candida, or tetanus antigen confirms the negative PPD result BIBLIOGRAPHY Centers for Disease Control and Prevention: Emergency preparednesss and response, bioterorism agents/disease, A-Z, by category Retrieved from http://emergency.cdc.gov/agent/agentlist-category.asp Centers for Disease Control and Prevention: Healthcare-associated infections (HAIs) Carbapene-resistant enterobacteriaceae (CRE) Retrieved from http://www.cdc.gov/HAI/organisms/cre/index.html Centers for Disease Control and Prevention: Rodents, diseases directly transmitted by rodents Retrieved from http:// 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28, 2008 from http://www.cdc.gov/flu/avian/gen-info/qa.htm Centers for Disease Control and Prevention: Get Smart for Healthcare, Clinician Guide, August 9, 2012 Inglesby TV, et al: Plague as a biological weapon: Medical and public health management JAMA 283:2281–2290, 2000 Miller J, Engelberg S, Broad W: Germs: Biological weapons and America’s secret war New York, Touchstone/ Simon & Schuster, 2002 Stern EJ, Uhde KB, Shadomy SV, Messonnier N Conference report on public health and clinical guidelines for anthrax Emerg Infect Dis, 2008 Available at: http://wwwnc.cdc.gov/eid/article/14/4/07-0969.htm Tille PM: Bailey and Scott’s Diagnostic Microbiology, 13th ed St Louis, Mosby, 2013 U.S Department of Health and Human Services: Primary Containment for Biohazards: Selection, Installation and Use of Biological Safety Cabinets, 3rd ed Atlanta, Centers for Disease Control and Prevention, 2007 U.S Preventive Services Task Force: Guide to Clinical Preventive Services, Rockville, MD, Agency for Healthcare Research and Quality, 2012 Versalovic J, Carroll KC, Funke G, Jorgensen JH, Landry ML, Warnock DW (eds): Manual of Clinical Microbiology, 10th ed Washington, DC, ASM Press, 2011 Winn W, Allen S, Janda W, Koneman E, Procop G, Schreckenberger P, Woods G: Color Atlas and Textbook of Diagnostic Microbiology, 6th ed Philadelphia, Lippincott Williams & Wilkins, 2005 Wormser, et al The clinical assessment, treatment, and prevention of lyme disease, human granulocytic anaplasmosis, and babesiosis: Clinical practice guidelines by the Infectious Diseases Society of America Clin Infect Dis 43(9):1089–1134, 2006 doi: 10.1086/508667 Retrieved from http://www.idsociety.org/uploadedFiles/IDSA/ Guidelines-Patient_Care/PDF_Library/Lyme%20Disease.pdf Wu AHB: Tietz Clinical Guide to Laboratory Tests, 4th ed Philadelphia, Saunders Elsevier, 2006 Fischbach_Ch07_printer_file.indd 548 11/4/13 10:22 PM ...Frontmatter Title A MANUAL i OF Laboratory and Diagnostic Tests NINTH EDITION Fischbach_FM_printer_file.indd i 11 /4 /13 10 :43 PM Fischbach_FM_printer_file.indd ii 11 /4 /13 10 :43 PM A MANUAL OF Laboratory. .. Diagnostic Testing Source of Standards for Diagnostic Service TABLE 1. 3 Standards for Diagnostic Evaluation ● 11 /4 /13 10 :18 PM Standards for Diagnostic Testing Clinical laboratory personnel and. .. follow-up, and case management Professional practice parameters of American Nurses Association (ANA), American Medical Association (AMA), American Society for Clinical Pathology (ASCP), American College