[Determination of serum calcitonin using a non-commercial RIA method].

A radioimmunoanalytical determination of the immunoreactive calcitonine in the humen serum was worked out using the authors' own specific antiserum, the preparation and properties of which are reported in the present paper. The precision and reliability of the analytical procedure is within the usual limits (the intraserial variation coefficient was 8.6%, the calculated sensitivity was 6 pg/ml). The reported procedure was employed to determine calcitonine in a larger number of patients who were examined because of suspected medullar carcinoma of the thyroid gland and in patients suffering from other thyropathies. The results are discussed from the viewpoint of heterogeneity of calcitonine in the circulation.