Radioimmunoassay for the Measurement of Pregnancy-Associated Plasma Protein-A (PAPP-A) in Humans

Abstract

A solid phase, second antibody radioimmunoassay technique has been developed for the measurement of human pregnancy-associated plasma protein-A (PAPP-A). This radioimmunoassay is specific and sensitive enough to measure PAPP-A in maternal plasma throughout pregnancy and in nonpregnant subjects. The sensitivity range is considerably wider than for the previously described rocket immunoelectrophoretic assay. The results obtained indicate that PAPP-A is not pregnancy specific but pregnancy-associated and also strongly suggest that there must be another production site for PAPP-A in addition to the placenta.