Serum T3 and T4 determinations during the TRH test as a complement to improved discriminatory power in suspect hyperthyroidism.

The aim of the study was to determine whether the addition of T3 and T4 determination in connection with a routine TRH-test could increase the discriminatory power of the test. Thus, forty-one patients with suspect hyperthyroidism were examined and samples for T3 and T4 and TSH determinations were drawn prior to the administration of TRH and at 20 and 60 min thereafter. The results showed that the addition of these thyroid hormone estimations did not increase the clinical value of the TRH-test.