Use of Heterophilic Antibody Blocking Agent (HBT) in Reducing False-Positive hCG Results

Abstract

The USA hCG Reference Service aids physicians in the interpretation of discordant or irregular human chorionic gonadotropin (hCG) results that do not concur with physical findings. The Service has now observed 24 cases of false-positive hCG results (14–571 IU/L). All have been cases erroneously diagnosed with choriocarcinoma or gestational trophoblast disease without demonstrable pregnancy or tumor (1)(2)(3)(4). Because of false-positive hCG results, patients have needlessly received chemotherapy, hysterectomy, and/or other surgery. The suspected cause for serum false-positive hCG is the presence of heterophilic antibodies that bind both capture and detection antibodies, effectively bridging them in the same way as the target antigen should in a standard ELISA format. Until recently, …