The laboratory approach to thyroid disease.

The author reviews thyroid-function tests from the viewpoint of clinical use of the more modern tests of basic thyroid function. Particular attention is paid to the changing use of the TSH assay, with the advent of the "sensitive" TSH tests. Following an overview of relevant physiology, the tests and their current indications are assessed. Finally, the newer strategies of measuring thyroid function are discussed by means of an example recommended by many authors, and a recommendation is made for adoption of such a strategy in the reader's laboratory.