Comparison of two immunoassay systems for hCGβ and PAPP-A in prenatal screening for trisomy 21, 18, and 13 in the first trimester

The screen positive rate for T21 (5.1%) did not differ between the two analytical platforms in our screening population, although PAPP-A measurements form Cobas were significantly lower than those from Kryptor. The calculated risks for the pregnancies affected by trisomies using hCGβ MoM and PAPP-A MoM from Kryptor agreed well with those from Cobas.