[Is a TSH screening for the diagnosis or exclusion of functional thyroid autonomy meaningful?]

A normal baseline TSH serum concentration is accepted as excluding thyroid dysfunction. The present study examined the usefulness of that concentration as a screening test for functional autonomy. 310 patients were retrospectively examined. They were all clinically euthyroid and had normal peripheral thyroid hormone concentrations. The positive predictive value for the confirmation of autonomy was 55.5%, the negative predictive value for the exclusion of autonomy 87.7%, using 0.5 mU/l as a lower limit. The probability for the presence of thyroid autonomy in patients with a TSH serum concentration below 0.3 mU/l was 72.5%.