[Maternal biochemical screening -- an approach for genetic prevention. part 2. sequential approach with integrated...

Performance of 2,5 year experience onprenatal (maternal) screening by integrated risk for Down syndrome and Edwards syndrome is presented in pregnant women underwent first (11(+0)-13(+6) g.w) and second trimester screening (14(+4)-19(+3) g.w), assessed by an integrated risk. Since the end of 2010 the most common strategy has been combination of both risks after contingent screening approach (serummarkers and US measurments from first test with indication to second trimester screening if the risk is intermediate or high and CVS diagnosis has been refused). Serummarkers were measured by fluorimetric immunoassay (Delfia) and risks were calculated using LifeCycle 3.2 software.

The test was performed on 491 women, less than 4452 and 13 016 women first and second trimester respectively. We found highrisk for a chromosome disorder in 32 (6,5%) cases: 19 (6,35%) women < 35 and 13 (6,7%) women > 35). Diagnosis of a chromosome diseases was found in 4 fetuses out of 32 (12,5%): 3 fetuses with trisomy 21 and 1 with trisomy 18. False positive results were found in 28 out of 491 (5,7%) women. Verified diagnosis on lyfor DS was found in 3 out of 4 cases (75% sensitivity), and false negative results in 25%. Discussion is focused on the comparison of the screening approaches - the sensitivity, limitation sand the step wise sequential testing way with integrated risk of achieving a high performance of screening.