The Quest Diagnostics Manual Endocrinology Test Selection and Interpretation Fourth Edition The Quest Diagnostics Manual Endocrinology Test Selection and Interpretation Fourth Edition Edited by: Delbert A. Fisher, MD Senior Science Officer Quest Diagnostics Nichols Institute Professor Emeritus, Pediatrics and Medicine UCLA School of Medicine Consulting Editors: Wael Salameh, MD, FACP Medical Director, Endocrinology/Metabolism Quest Diagnostics Nichols Institute San Juan Capistrano, CA Associate Clinical Professor of Medicine, David Geffen School of Medicine at UCLA Richard W. Furlanetto, MD, PhD Medical Director, Endocrinology/Metabolism Quest Diagnostics Nichols Institute Chantilly, VA ©2007 Quest Diagnostics Incorporated. All rights reserved. Fourth Edition Printed in the United States of America Quest, Quest Diagnostics, the associated logo, Nichols Institute, and all associated Quest Diagnostics marks are the trademarks of Quest Diagnostics. All third party marks − ®' and ™' − are the property of their respective owners. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, and information storage and retrieval system, without permission in writing from the publisher. Address inquiries to the Medical Information Department, Quest Diagnostics Nichols Institute, 33608 Ortega Highway, San Juan Capistrano, CA 92690-6130. Previous editions copyrighted in 1996, 1998, and 2004. Re-order # IG1984 Forward Quest Diagnostics Nichols Institute has been committed to providing state of the art endocrine testing for nearly 4 decades. During this time, we have introduced assays for most of the endocrine systems hormones, important metabolites and carrier proteins, free hormones, many hormone receptors, endocrine system autoantibodies, relevant chromosomal abnormalities, and selected genetic mutations. Our commitment to state of the art diagnostics and our dedication to quality and service have always included both adult and pediatric patients, and we have an ongoing program providing adult and pediatric reference range and clinical correlations data. Additionally, we have special procedures for identification and handling of pediatric samples, including reduced sample volume, whenever possible. In this manual, we have consolidated detailed technical information for more than 150 of the endocrine and endocrine-related tests performed at Nichols Institute. The manual includes an overview of the physiology of each endocrine system, the diagnostic applications of each test, interpretation of test results, and a catalog of the endocrine-related dynamic or perturbation tests that facilitate diagnosis and patient management. For your convenience, we have included a guide for interconversion of conventional and SI units for our endocrine tests. In addition, we have indexed our endocrine tests in several formats to provide easier access to the information. National Quest Diagnostics test codes are listed for each of the tests described in the Alphabetical Test section. Methodologies may differ for the non-Nichols Institute regional laboratory tests; information and reference ranges for these tests are available from your sales representative or regional laboratory personnel. We trust that the manual will assist you in the diagnosis and management of your adult and pediatric patients and reiterate our commitment at Quest Diagnostics to provide you with the highest quality test results and ready availability of consultative services. Our laboratory staff and our Medical and Scientific Directors are available for consultation to help assure the most efficacious resolution of complex or confusing endocrine problems. We welcome your feedback and suggestions for improving our service to you. Delbert A. Fisher, MD Senior Science Officer Quest Diagnostics Nichols Institute v Acknowledgments Normative data were developed by the Clinical Correlations department under direction of Dr. Richard Reitz, Esther Carlton, and Collette Scheele. Text development, overall composition, and project direction were accomplished by Patricia Vendely. Mary Jane Michel assisted with typing; Lorraine Saunders was responsible for formatting; and Lynn Ricard helped with proofing. For their dedicated contributions, the editor is indeed grateful. Delbert A. Fisher, MD vi Contents Page Forward ....................................................................................................................v Acknowledgments ..............................................................................................vi Endocrine Test Categories and Associated Tests Adrenocortical Function ........................................................................................ 3 Cardiovascular/Lipids ............................................................................................ 4 Catecholamines....................................................................................................... 5 Congenital Adrenal Hyperplasia (CAH)............................................................... 5 Endocrine Autoimmunity....................................................................................... 5 Fluid, Electrolyte, and Renal.................................................................................. 6 Genetic (Biochemical and Cytogenetic) ............................................................... 7 Gonadal Function ................................................................................................... 8 Growth and Growth Hormone............................................................................... 9 Hypothalamic and Pituitary Function ................................................................... 9 Metabolic (Including Diabetes Mellitus) and Gastrointestinal Disorders......... 10 Multiple Endocrine Neoplasia ............................................................................. 11 Parathyroid and Mineral Metabolism.................................................................. 12 Thyroid Function .................................................................................................. 12 Additional Diagnostic Profiles.............................................................................. 13 Perturbation Tests................................................................................................. 14 Alphabetical Test Section See Test Index for list of tests included in this section....................................... 15 Test Application and Interpretation Preface................................................................................................................. 189 Disorders of Adrenal Function Background Physiology .................................................................................190 Adrenal Insufficiency ..................................................................................... 193 Adrenal Biosynthetic Enzyme Deficiencies .................................................. 193 Classical Congenital Adrenal Hyperplasia (CAH) ................................... 193 Nonclassical Disease (Partial Deficiency in Steroid Biosynthesis) .......... 205 Cushing's Syndrome ................................................................................... 206 Renin-Angiotensin – Aldosterone System (RAAS) ....................................... 207 Background Physiology............................................................................... 207 Assessment of Disorders of the RAAS ........................................................ 208 Primary Aldosteronism ........................................................................... 210 Renovascular Hypertension.................................................................... 210 Dexamethasone-suppressible Hyperaldosteronism .............................. 211 Pseudohypoaldosteronism...................................................................... 211 Adrenal Diagnosis via Urine GC/MS Metabolite Analysis .......................... 211 vii Contents Page References ....................................................................................................... 215 Disorders of Anterior Pituitary Function Background Physiology .................................................................................. 217 Hypopituitarism .............................................................................................. 218 Pituitary Adenomas......................................................................................... 220 General Features ......................................................................................... 220 Prolactinoma ............................................................................................... 221 Acromegaly.................................................................................................. 222 Cushing's Disease ........................................................................................ 223 Thyrotropinoma.......................................................................................... 223 Gonadotropinoma ...................................................................................... 223 References ....................................................................................................... 224 Disorders of Calcium and Bone Metabolism Background Physiology ................................................................................. 225 Laboratory Assessment of Disorders of