THE SCREENING OF PATIENTS WITH SUSPECTED THYROTOXICOSIS USING A SENSITIVE TSH RADIOIMMUNOASSAY

Abstract
A radioimmunoassay was optimized to measure serum TSH with maximum sensitivity (sTSH). With this assay sTSH was < 0.5 mIU/l in 100% of 64 patients with proven thyrotoxicosis and > 0.5 mIU/l in 92% of 76 normal subjects. sTSH correctly predicted the TSH response to TRH (.DELTA. TSH) in 93% of 125 patients with suspected thyrotoxicosis. In this group thyrotoxicosis was excluded by an sTSH > 0.5 mIU/l in 52% of patients thus avoiding the need for further testing.