Competitive enzyme immunoassay for human chorionic somatomammotropin using the avidin-biotin system

Abstract Human chorionic somatomammotropin (HCS) is determined by an enzyme immunoassay where HCS competes with biotin-labeled HCS for insolubilized anti-HCS antibodies. Enzymelabeled avidin is then used to reveal the amount of bound HCS. The system proves to be sensitive (1 ng/ml of HCS can be detected) and results agree with radioimmunoassay determinations (correlation coefficient = 0.979). Kinetics of the avidin-biotin reaction and coating of polystyrene wells are also investigated.