CORRELATION BETWEEN PER CENT DISCHARGE OF THIOCYANATE TEST AND THYROID FUNCTIONS IN PATIENTS WITH HASHIMOTO'S DISEASE

ABSTRACT The thiocyanate test was carried out in 18 patients with Hashimoto's disease. Thiocyanate was given orally several hours after the administration of tracer doses of 131I when the thyroid counts seemed to have reached a plateau. The per cent discharge of thiocyanate test was significantly higher in the groups with lower level of T4 (< 5.5 μg/100 ml), RSU (<25.5%) and BMR (<+2.5 %), and higher levels of TSH (> 10.0 μU/ml). A chi-square (ϰ2) test with Yates correction led to ϰ2 = 3.56 (1 df) with P=0.06 (per cent discharge vs T4, RSU, BMR and TSH). Then the per cent thiocyanate discharge was increased with the degree of hypothyroidism in patients with Hashimoto's disease. The correlation between the per cent discharge and 131I 24 h uptake was not significant. It was apparent that the iodide concentration mechanism was present even in the severe hypothyroid stage of Hashimoto's disease. This disproportion between the uptake of iodide and the iodide organification may result in the increase in unbound iodide. It is concluded that the hypothyroidism in Hashimoto's disease may not be caused by a defect in iodide organification, even if it correlated to the degree of hypothyroidism.