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Article
March 16, 1990

American Thyroid Association Guidelines for Use of Laboratory Tests in Thyroid Disorders

Author Affiliations

From the Department of Medicine, Montefiore Medical Center and The Albert Einstein College of Medicine, Bronx, NY (Dr Surks); Department of Medicine, University of California—Los Angeles (Drs Chopra and Solomon); Department of Medicine, University of Minnesota College of Medicine, Minneapolis (Dr Mariash); and Department of Medicine, University of Southern California School of Medicine, Los Angeles (Dr Nicoloff).

From the Department of Medicine, Montefiore Medical Center and The Albert Einstein College of Medicine, Bronx, NY (Dr Surks); Department of Medicine, University of California—Los Angeles (Drs Chopra and Solomon); Department of Medicine, University of Minnesota College of Medicine, Minneapolis (Dr Mariash); and Department of Medicine, University of Southern California School of Medicine, Los Angeles (Dr Nicoloff).

JAMA. 1990;263(11):1529-1532. doi:10.1001/jama.1990.03440110095035
Abstract

Selection of appropriate laboratory determinations will enable the clinician to diagnose thyroid dysfunction readily in the majority of patients. At the present time, estimation of free thyroxine and a "sensitive" thyrotropin assay are recommended as the principal laboratory tests for thyroid disease. A decrease in serum free thyroxine estimate and a raised level of serum thyrotropin confirm the diagnosis of hypothyroidism caused by thyroid gland failure. An increase in free thyroxine estimate combined with a serum sensitive thyrotropin level suppressed to less than 0.1 mU/L establishes the diagnosis of thyrotoxicosis. In sick patients, a normal or raised serum free thyroxine estimate together with a normal level of serum thyrotropin suggests that the patient has neither hypothyroidism nor thyrotoxicosis. Patients with severe illnesses, generally in the intensive care unit, and those treated with certain drugs, as well as individuals with unusual thyroid disorders, may present with confusing laboratory findings. An understanding of the regulation of the thyroid hormone system and/or judicious consultation with an endocrinologist should enable the clinician to diagnose thyroid disease, if present, in such patients.

(JAMA. 1990;263:1529-1532)

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