Coagulation Disorders Quality in Laboratory Diagnosis Diagnostic Standards of Care MICHAEL LAPOSATA, MD, PHD Series Editor Coagulation Disorders Quality in Laboratory Diagnosis Michael Laposata, MD, PhD Forthcoming in the Series Clinical Microbiology Diagnostic Standards of Care Series Coagulation Disorders Quality in Laboratory Diagnosis Michael Laposata, MD, PhD Edward and Nancy Fody Professor and Executive Vice Chair of Pathology Professor of Medicine Vanderbilt University School of Medicine Pathologist-in-Chief Vanderbilt University Hospital Nashville, Tennessee New York Acquisitions Editor: Richard Winters Cover Design: Joe Tenerelli Compositor: S4Carlisle Publishing Services Printer: Hamilton Printing Company Visit our website at www.demosmedpub.com © 2011 Demos Medical Publishing, LLC. All rights reserved. This book is protected by copyright. No part of it may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. M edicine is an ever-changing science. Research and clinical experience are continually e xpanding our knowledge, in particular our understanding of proper treatment and drug therapy. The authors, editors, and publisher have made every effort to ensure that all information in this book is in a ccordance with the state of knowledge at the time of production of the book. N evertheless, 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, express or implied, with respect to the contents of the publication. Every reader should examine carefully the package i nserts accompanying each drug and should carefully check whether the dosage schedules men- tioned therein or the contraindications stated by the manufacturer differ from the statements made in this book. Such examination is particularly important with drugs that are either rarely used or have been newly released on the market. Library of Congress Cataloging-in-Publication Data Laposata, Michael. Coagulation disorders: quality in laboratory diagnosis / Michael Laposata. p. cm.—(Diagnostic standards of care) Includes bibliographical references and index. ISBN 978-1-933864-82-2 (alk. paper) 1. Blood coagulation disorders—Diagnosis. 2. Diagnosis, Laboratory. I. Title. II. Series: Diagnostic standards of care. [DNLM: 1. Blood Coagulation Disorders—diagnosis. 2. Anticoagulants—therapeutic use. 3. Blood Coagulation—physiology. 4. Clinical Laboratory Techniques—methods. 5. Medical Errors—prevention & control. WH 322 L315c 2011] RC647.C55L37 2011 616.1(cid:2)57075—dc22 2010021811 Special discounts on bulk quantities of Demos Medical Publishing books are available to corporations, professional associations, pharmaceutical companies, health care organizations, and other qualifying groups. For details, please contact: Special Sales Department Demos Medical Publishing 11 W. 42nd Street, 15th Floor New York, NY 10036 Phone: 800–532–8663 or 212–683–0072 Fax: 212–941–7842 E-mail: [email protected] Made in the United States of America 10 11 12 13 14 5 4 3 2 1 To my wonderful brother, Sam, 12 years my senior, who has loved, inspired, mentored, and emotionally supported me for my entire life. Contents Series Foreword ix Preface xi Acknowledgments xiii 1 Monitoring of Anticoagulant Therapy in Patients Being Treated with Warfarin 1 2 Monitoring of Anticoagulant Therapy in Patients Being Treated with Unfractionated Heparin 11 3 Monitoring of Anticoagulant Therapy in Patients Being Treated with Low Molecular Weight Heparin 23 4 Monitoring of Anticoagulant Therapy in Patients Being Treated with Fondaparinux 35 5 Monitoring of Anticoagulant Therapy in Patients Being Treated with Lepirudin or Argatroban 43 6 Evaluation for Heparin-induced Thrombocytopenia 49 7 Evaluation of Prolongations of the PT and the PTT and Assessment for Defi ciencies of Coagulation Factors 59 8 Evaluation for Disseminated Intravascular Coagulation 75 9 Evaluation for a Congenital Hypercoagulable State 85 viii Contents 10 Evaluation for Antiphospholipid Antibodies 99 11 Evaluation for von Willebrand Disease 107 12 Evaluation for a Coagulation Factor VIII Inhibitor 115 13 Evaluation for Thrombocytopenia That Is Not Associated with Heparin Exposure 121 14 Evaluation for Platelet Dysfunction in the Presence or Absence of Antiplatelet Agents 131 Annotated Bibliography 139 Index 141 Series Foreword “ Above all, do no harm.” This frequently quoted admonition to healthcare providers is highly regarded, but despite that, there are few books, if any, that focus primarily on how to avoid harming patients by learning from the mistakes of others. Would it not be of great benefit to patients if all health care providers were aware of the thrombotic consequences from heparin induced thrombocytopenia before a patient's leg is ampu- tated? The clinically significant, often lethal, thrombotic events that occur in patients who develop heparin induced thrombocy- topenia would be greatly diminished if all health care providers appropriately monitored platelet counts in patients being treated with intravenous unfractionated heparin. It was a desire to learn from the mistakes of others that led to the concept for this series of books on diagnostic standards of care. As the test menu in the clinical laboratory has enlarged in size and complexity, errors in selection of tests and errors in the interpreta- tion of test results have become commonplace, and these mistakes can result in poor patient outcomes. This series of books on diag- nostic standards of care in coagulation, microbiology, transfusion medicine, hematology, clinical chemistry, immunology, and labo- ratory management are all organized in a similar fashion. Clinical errors, and accompanying cases to illustrate each error, are presented within all of the chapters in several discrete categories: errors in test selection, errors in result interpretation, other errors, and diagnostic controversies. Each chapter concludes with a summary list of the standards of care. The most common errors made by thousands of healthcare providers daily are the ones that have been selected for presentation in this series of books.