The Quest Diagnostics Manual: Endocrinology: Test Selection and Interpretation

382 Pages·2007·3.164 MB·English

by  Delbert A. Fisher, Quest Diagnostics

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
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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
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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 Calcium Metabolism .....................226
Evaluation of Hypercalcemia .....................................................................228
Evaluation of Hypocalcemia.......................................................................229
Vitamin D Deficiency......................................................................................230
Vitamin D Metabolism in Renal Failure........................................................230
Metabolic Bone Disease .................................................................................232
Clinical Application of Bone Markers........................................................233
Diagnosis of Bone Disorders .................................................................233
Diagnosis of Osteoporosis......................................................................236
Efficacy of Therapy.................................................................................236
Follow-up to Therapy..............................................................................236
References.......................................................................................................236
Disorders of Carbohydrate Metabolism
Background Physiology..................................................................................239
Hyperglycemic Disorders...............................................................................239
Type 1 Diabetes...........................................................................................240
Maturity Onset Diabetes of the Young (MODY).......................................243
Type 2 Diabetes...........................................................................................243
Diagnosis of Diabetes Mellitus....................................................................244
Preventing and Managing Complications.................................................244
Hypoglycemic Disorders.................................................................................248
Diagnostic Approach..................................................................................249
References.......................................................................................................251
Disorders of Gonadal Function
Background Physiology..................................................................................255
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Contents
Page
Development of the Hypothalamic–Pituitary Axis and Isolated
GnRH Deficiency ........................................................................................255
Regulation of Pubertal Onset.....................................................................256
Regulation of the Mature Hypothalamic–Pituitary–Gonadal Axis...........256
Gonadal Determination and Differentiation............................................259
Measurement of Pituitary–Gonadal Axis Hormones....................................261
Luteinizing Hormone.................................................................................261
Follicle Stimulating Hormone....................................................................261
Estrogens......................................................................................................261
Testosterone.................................................................................................262
Sex Hormone Binding Globulin................................................................263
Inhibin.........................................................................................................263
Abnormalities of Sexual Determination and Differentiation......................263
Disorders of Sexual Maturation.....................................................................264
Normal Puberty Staging.............................................................................264
Timing of Physical Changes of Puberty.....................................................264
Normal Variants of Puberty........................................................................266
Precocious Puberty......................................................................................267
Delayed or Absent Puberty.........................................................................267
Disorders of Testicular Function....................................................................269
Developmental Disorders...........................................................................269
Disorders of the Germinal Cells.................................................................269
Testicular Aging...........................................................................................271
Disorders of Ovarian Function.......................................................................272
Premature Ovarian Failure.........................................................................273
Polycystic Ovarian Syndrome.........................................................................274
Assessment of Functional Gonadal Tumors..................................................275
References.......................................................................................................276
Disorders of the Growth Hormone–Insulin-like Growth Factor Axis
Background Physiology .................................................................................279
Growth Hormone Deficiency in Children.....................................................282
Growth Hormone Deficiency in Adults.........................................................283
Growth Hormone Excess ...............................................................................284
Laboratory Assessment of the Growth Hormone – IGF Axis.......................284
Insulin-like Growth Factors and Binding Proteins ...................................285
Growth Hormone Dynamic Testing...........................................................289
References ......................................................................................................290
Disorders of Thyroid Function
Background Physiology..................................................................................293
Differential Diagnosis of Thyroid Disorders.................................................295
Primary Hypothyroidism.............................................................................298
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