Evaluation of beta-subunit chorionic gonadotropin as an aid in diagnosis of trophoblastic disease

The advent of the radioimmunoassay of Beta subunit chorionic gonadotropin (BhCG) has eliminated a major problem in following the patient with gestational trophoblastic neoplasia (GTN). Whole hCG cross reacts with luteinizing hormone (hLH) causing difficulties when GTN patient titers fall to levels coincidental with pituitary levels of hLH. The use of the Beta subunit of hCG in radioimmunoassay has eliminated this problem because there is essentially no cross reaction between the B-subunit of the hCG and hLH. A review of the use of this sensitive assay in the management of patients with GTN is presented.