[TSH receptor antibody determination using the TSH radioreceptor antibody assay in clinical practice]

We tested the clinical valency of the TSH-receptor antibody (TBIAb) determination (TRAK assay, Fa. Henning) for the differential diagnostics of various diseases of the thyroid gland (n = 259), particularly of the hyperthyroidism. In 110 out of 114 basedowians TBAIAb could be proved (sensitivity 96%). The specifity to healthy persons (n = 20) was 100%, to the disseminated autonomy (n = 61) 92%. In 43 bland strumas and 22 cases of primary hypothyroidisms no circulating TBIAb were found. Of 40 cases of Basedow's hyperthyroidism the TBIAb titres were pursued during a 12-month methimazol therapy. In these cases was shown that negative antibody titres at the end of the treatment were connected with an essentially lower rate of early relapses than positive ones. Moreover, a highly dosed application of methimazol revealed a more favourable tendency than a low dosed one. From this we conclude that the TBIAb measurement with a commercial kit is a sensitive, sufficiently specific and practicable method for the differential diagnostics of hyperthyroidism and that to a certain degree it allows conclusions on the course of Basedow's disease after thyrostatic long-term therapy.