[Study of discrepancies between "ultra-sensitive" TSH and thyroid hormones levels]

TSH levels were determined by "ultra-sensitive" assay (TSH-US) in 1300 sera and compared to thyroid hormone (TH = TT3 and FT4) values. Discordant results were observed in 186 cases divided into 3 groups according to TSH-US and TH values. Clinical data obtained in discordant cases showed that most of the subjects (75%) were under treatment (antithyroid drugs, suppressive or replacement hormone therapy) or had been treated by surgery or 131I when the sera were drawn. Among the patients who had not been treated (25%) we found moderate or subclinical hyperthyroidism (toxic adenoma or goitre) or hypothyroidism. In conclusion, most of the discordant results proved consonant when the clinical or therapeutic data were taken into account.