PAPP-A ELISA

An enzyme immunoassay for the quantitative measurement of pregnancy associated plasma protein A (PAPP-A) in serum and plasma. PAPP-A is a protein produced by the developing placenta. Its concentration in the maternal blood increases rapidly after the 7th week of pregnancy. The measurement of PAPP-A in the first trimester of pregnancy has been reported as a useful marker in antenatal screening for Down Syndrome and other fetal aneuploidies. Reduced PAPP-A values in combination with maternal age, the measurement of free ß-HCG and the ultrasonic determination of nuchal translucency (NT) in pregnancy weeks 11 to 14 may detect up to 90 % ofpregnancies with Down syndrom (reference 7). The DRG PAPP-A ELISA EIA-2397 may be used for the risk assessment of Down´s syndrom (trisomy 21) in the first trimester of pregnancy. For the risk assessment of trisomy 21 and other fetal aneuploidies PAPP-A should always be measured in combination with other analytes (for example free ß-HCG and NT, see above) and a special software for the risk assessment of trisomy 21. According to the IVD Directive (98/79/EC) both software and kits for the additional analytes must be suitable for trisomy 21 screening and CE-certified by a notified body, indicated by the identification number of the notified body on the CE-mark on software and kits. The DRG PAPP-A ELISA Kit is a solid phase enzyme-linked immunosorbent assay (ELISA) based on the sandwich principle. The microtiter wells are coated with a polyclonalanti PAPP-A antibody. An aliquot of patient sample containing endogenous PAPP-A is incubated in the coated well with assay buffer. After incubation the unbound material is washed off. In the second incubation step a sandwich complex is formed with a polyclonal anti PAPP-A antibody peroxidase conjugate. Having added the substrate solution, the intensity of color developed is proportional to the concentration of PAPP-A in the patient sample.