Free Thyroxine Levels in Critically III Patients
A Comparison of Currently Available Assays
- Michael F. Slag, MD;
- John E. Morley, MB, BCh;
- Michael K. Elson, PhD;
- Kingsley R. Labrosse, PhD;
- Terry W. Crowson, MD;
- Frank Q. Nuttall, MD, PhD;
- Rex B. Shafer, MD
- From the Sections of Metabolism and Endocrinology (Drs Slag, Morley, and Nuttall) and Nuclear Medicine (Drs Elson and Shafer), Veterans Administration Medical Center, and the Department of Medicine, University of Minnesota (Drs Slag, Morley, Crowson, Nuttall, and Shafer), Minneapolis, and the Departments of Pathology (Dr Labrosse) and Internal Medicine (Dr Crowson), St Paul-Ramsey Medical Center, St Paul.
Abstract
Two indices of free thyroxine (T4) and four methods of free T4 measurement were compared in 85 patients with acute illness, hospitalized in intensive care units. All of the methods of free T4 measurement in critical illness were nonspecific, and two of the methods failed to suggest hypothyroidism in two patients with primary hypothyroidism and another associated critical illness. Since the ideal screening test should be both sensitive and specific, all tests for free T4 used in this study should be interpreted with caution in severely ill patients.
(JAMA 1981;246:2702-2706)
Footnotes
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Reprint requests to Section of Endocrinology and Metabolism, Veterans Administration Medical Center, Minneapolis, MN 55417 (Dr Slag).
