Abstract: Abstract Objective: To develop an Enzyme immunoassay for testing the concentration of pregnancy-associated plasma protein A, the indirect-coating plates were adopted. Methods: The plates were coated with biotinylation bovin serum albumin and avidin-enzyme-linked. A biotin-labeled antibody for PAPP-A was used as catching antibody to capture the antigen of PAPP-A in the sample. The another antibody for PAPP-A that labeled with horseradish peroxidase was used as detecting antibody to test the concentration of pregnancy-associated plasma protein A in human serum. Results: The sensitivity of the assay we developed was 0.31μg/ml and its recovery rates all between 95% and 100%.The linearity, stability and specificity of the assay are good. The three serum samples that the concentration of PAPP-A each at low, middle and high levels were tested repeatedly 10 times, showing that the CVs inner the group all did not exceed 10% and the CVs between groups all did not exceed 15%.The assay we developed was done the analysis associativity with enzyme immunoassay kit abroad, r=0.982, which indicated the two assays were correlated greatly. Conclusion: Using indirect-coating technology, the assay we established to determine PAPP-A is sensitive and accurate, and the stability is good. There are greatly correlated between the assays, we developed and abroad.

Key words: pregnancy-associated plasma protein A, Indirect-coating technology, Enzyme immunoassay