Clinical perspectives in the diagnosis of thyroid disease.

BACKGROUND The wide array of available thyroid diagnostic tests can help provide accurate diagnoses for most cases of thyroid disease but can be confusing and costly when used inappropriately. METHODS Published articles were reviewed and combined with the author's clinical experience and data collected from patients. RESULTS The discussions focus on confusing aspects of thyroid diagnostic tests, the use and limitations of the thyrotropin test to screen for thyroid dysfunction, biological factors that complicate the interpretation of this and other thyroid diagnostic tests, and a combined clinical and laboratory approach to (a) thyroid diseases with only one important dimension ("simplex" conditions) and (b) thyroid diseases with several important dimensions ("multiplex" conditions). CONCLUSION The optimal use of thyroid diagnostic tests is patient-specific and depends on the patient's specific thyroid disease, the stage of disease, and coexisting medical conditions.