Eagle Biosciences b-HCG ELISA Assay Kit for b-HCG is based on the simultaneous capture of HCG by a monoclonal antibody immobilized on the microplate and directed against the b-HCG fraction, and another monoclonal antibody conjugated with peroxidase horseradish (HRP) and directed against the fraction a-HCG. Sample Types: serum, plasma. Range: 1 - 400 mIU/mL. Sensitivity: 0.09 mIU/mL. Time: 1.5 hours ? Human chorionic gonadotropin (HCG) is a glycoprotein hormone secreted in pregnancy, that is made by the embryo soon after conception and later by the syncytiotrophoblast (part of the placenta). Its role is to prevent the disintegration of the corpus luteum of the ovary and thereby maintain progesterone production that is critical for a pregnancy in humans. HCG may have additional functions, for instance it is thought that it affects the immune tolerance of the pregnancy.