Pregnancy-Associated Plasma Protein A (PAPP-A) is a protein used in first trimester screening tests. It is used to assess the risk that the fetus a pregnant woman is carrying has a chromosomal abnormality such as Down syndrome (trisomy 21) or Edwards syndrome (trisomy 18).

In first trimester screening it is used in conjunction with hCG or Free beta hCG as well as other diagnostic tests such as nuchal translucency. It offers the benefit of Down syndrome prediction (as a probability factor) earlier in the pregnancy but first trimester screening does not assess risk of of neural tube defects, such as spina bifida.

Please see Monobind's  assay for second trimester screening product.