Clinical perspectives in the diagnosis of thyroid disease

Background: The wide array of available thyroid diagnostic tests can help p rovide accurate diagnoses for most cases of thyroid disease but can be conf using and costly when used inappropriately. Methods: Published articles were reviewed and combined with the author's cl inical experience and data collected from patients. Results: The discussions focus on confusing aspects of thyroid diagnostic t ests, 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 ("simpl ex" 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 diseas e, and coexisting medical conditions. (C) 1999 American Association for Cli nical Chemistry.