THE 131I-TRIIODOTHYRONINE-RESIN UPTAKE TEST

Abstract

SUMMARY: The results of 450 ¹³¹I-triiodothyronine (T₃)-resin uptake tests in euthyroid, hyper- and hypothyroid patients are described. The effects of variation in the temperature and weight of resin on ¹³¹I-T₃ uptake are demonstrated. Limits of normality have been established for a group of 149 euthyroid patients. The ¹³¹I-T₃-resin uptake test in euthyroid, hyper- and hypothyroid patients has been compared with the 4 and 48 hr. ¹³¹I neck uptake, the protein-bound iodine (p.b.i.) concentration and the basal metabolic rate (b.m.r.) as a test of thyroid status. The results suggest that, as a single test for the estimation of thyroid status, the ¹³¹I-T₃-resin uptake test is as reliable and more convenient than the more established test procedures.