Noninvasive prenatal testing (NIPT) for fetal trisomies in a routinely first-trimester screening

Results Results from chromosome selective sequencing were available from 253 cases of 255 cases. In two cases fetal cell fraction was below the minimal requirement of 4%. In this population of 255 cases we found euploid pregnancies in 250 cases and 5 aneuploid pregnancies: two trisomies 21, one trisomy 18, one triosmy 13 and one 45 XO. In 195 pregnant women, the performance of screening by combined test(NT, free B-HCG and PAPP-A, at the risk cutoff of 1: 150 as recommended by the Croatian National Screening Committee, was the detection of all cases of trisomies 21, 18 and 13 with atFPR of 4, 5% and one FNR(0, 39%) for tridomy 21. In screening by combined test and additional ultrasound markers(NT, NB, TR, DV, ACM) at risk cutoff of 1: 150, all cases of trisomies 21, 18 and 13 were detected at FPR 2, 5% and 0% FNR The performance of screening for trisomy 21 and trisomy 18 by NIPT using chromosome-selective sequencing is as effective with DR 99% and FPR < 1%, but performance of screening for trisomy 13 is as effective with DR 95% and FPR 4%.