METHOD FOR INCREASING THE ACCURACY OF THE RADIOIODINE UPTAKE AS A TEST FOR THYROID FUNCTION BY THE USE OF DESICCATED THYROID*†

Abstract

Differentiation of thyrotoxic and euthyroid patients by use of the suppressive effect of exogenous thyroid hormone on thyroidal radioiodine metabolism is described. Twenty-eight thyrotoxic and 55 euthyroid patients were studied. The test is most useful in patients with either a thyroidal uptake or clinical picture which is equivocal. Almost without exception goitrous and nongoitrous euthyroid patients showed a suppression of the 24-hour uptake below 20% following the administration of 540 mg thyroid daily for 1-2 weeks; the majority were suppressed below 20% by 180 mg daily for 1 week. In none of the thyrotoxic patients was suppression below 20% induced by a dose of 540 mg daily and in only one was such suppression induced by 720 mg daily.