Application of the radioreceptor assay for human chorionic gonadotropin in pregnancy testing and management of trophoblastic disease.

A commercially prepared radioreceptor assay (RRA) for human chorionic gonadotropin (hCG) has been evaluated as a pregnancy test and in a quantitative assay to follow patients with hydatidiform mole. The RRA demonstrated almost 100% agreement in comparison with radioimmunoassay (RIA) and urinary hCG tests. In the quantitative assay, a limiting reliable concentration of 70 mIU/ml of hCG in serum could be obtained. Extremely good correlation was achieved between the RRA and RIA test for hCG in 2 patients with hydatidiform mole over a span of 3 months of followup after evacuation of the mole. The usefulness of the RRA as a replacement of RIA tests for hCG is discussed.