Specificity and sensitivity of human chorionic gonadotropin radioimmunoassays. A comparison of two different approaches.

Two different procedures for determination of HCG in plasma from patients with testicular germ cell tumors, patients with benign disease, and normal controls were applied: (1) measurement of the amount of HCG and its beta-subunit, and (2) assay of the isolated beta-subunit alone. The test which measured the free beta-subunit and the HCG molecule gave 13% more sensitivity in patients with nonseminomatous germ cell tumors. The specificity in blood donors was 100% for both tests. In benign diseases the measurement of the complete molecule gave 100% specificity, whereas the other procedure had a specificity of 95%. For these reasons, the determination of the complete molecule seems to be preferable for patients with nonseminomatous germ cell tumors.