Abstract

Background: Pregnancy-associated plasma protein A (PAPP-A) was first found in the serum of pregnant women and then found to be associated with acute coronary syndrome (ACS). Unfortunately, the sensitivity and specific-ity of current detection methods are poor, so the present work aimed to improve them. The successful detection of PAPP-A could be widely applicable clinically.
Methods: We used affinity chromatography to purify the PAPP-A antigen, which was used to prepare the anti-body. A biotin-avidin enzyme-linked immunosorbent assay (BA-ELISA) was developed to detect low levels of PAPP-A. Nonspecific reactions were excluded by using affinity chromatography and papain digestion to remove the Fc fragment of the antibody.
Results: The BA-ELISA method we developed was more sensitive than traditional ELISA, as all nonspecific reac-tions were excluded. Its sensitivity was 0.065 mIU/L and recovery of PAPP-A from samples was 98.51%. The spec-ificity was also much better than with standard ELISA kits.
Conclusions: Affinity chromatography and papain digestion have important effects on the assay specificity. The BA-ELISA method proved sensitive and nonspecific reactions were excluded. The method is easily carried out, so it is suitable for detecting PAPP-A in the serum of patients with ACS.

DOI: 10.7754/Clin.Lab.2012.111002