A solid-phase luminescent immunoassay for human chorionic gonadotropin using Pholas dactylus bioluminescence

A solid-phase luminescent immunoassay (LIA), based on the light emission produced as a result of the oxidation of Pholas dactylus luciferin by horseradish peroxidase (HRP) in the presence of molecular oxygen, was developed for human chorionic gonadotropin (hCG). The light emitted in the presence of diethyldithiocarbamate permitted the detection of 0.1 fmol HRP. HRP retained most of its light-emitting capacity after coupling with purified anti-hCG antibody by glutaraldehyde. The LIA involved immobilization of the antigen in plastic tubes coated with purified anti-hCG antibody and detection of the immunocomplex by light emission in the presence of Pholas luciferin. Light emission was linear for antigen concentration within the range 0.5-100 ng/ml. LIA correlates reasonably well with RIA and has a comparable sensitivity (0.5 ng hCG/ml).

New horizons in hCG detection

The advent of high technology in the field of hCG measurement has created a greater requirement for high expertise in the analysis and evaluation of hCG levels, particularly low-positive levels, and for the concomitant clinical management of the patient. This implies an imperative to treat trophoblastic disease patients in trophoblast disease referral centers.