for Down syndrome
Quad Screen | Fß
The Quad Screen | Fß is performed in the second trimester of pregnancy, between 15 weeks and 21 weeks, 6 days gestation. The mother's serum is collected and sent to NTD Labs for analysis. This test analyzes 4 biomarkers found in the mother's serum - alpha-fetoprotein (AFP), free beta human chorionic gonadotrophin (hCG), unconjugated estriol, and inhibin-A. This test is essentially the same as Part 2 of the Sequential Screen | Fß. This test is suggested for patients who present too late in their pregnancy to receive first trimester screening.
The Quad Screen | Fß detects 75% of Down syndrome cases at a 5% false positive rate, and detects 75% of trisomy 18 cases at a 0.3% false positive rate. This test detects 90% of cases of open spina bifida and 98% of cases of anencephaly.