. Author manuscript; available in PMC: 2017 Aug 8.

Published in final edited form as: Obstet Gynecol Clin North Am. 2017 Jun;44(2):245–256. doi: 10.1016/j.ogc.2017.02.004

Table 3.

Characteristics of serum screening options for aneuploidy

Screening Test	Gestational Age at Screening (in wk)	Detection Rate for Trisomy 21 (%)	Screen Positive Rate (%)	Analytes and/or Measurements Obtained
First-trimester screen	10–13^*	82–87¹⁵	5	Nuchal translucency Papp-A hCG
Triple screen	15–22	69	5	hCG AFP uE3
Quad screen	15–22	81	5	hCG AFP uE3 DIA
Integrated	10–13 and 15–22	96	5	First-trimester screen, then quad screen
Sequential stepwise	10–13 and 15–22	95	5	First-trimester screen, then quad screen
Contingent screen	10–13 and 15–22	88–94	5	First-trimester screen, then quad screen
Cell-free DNA	Any age after 9 10 wk	99	0.5	Molecular evaluation of cell-free fetal DNA within maternal serum

Abbreviations: AFP, alpha-fetoprotein; DIA, dimeric inhibin-A; hCG, human chorionic gonadotropin; Papp-A, pregnancy-associated plasma protein A; uE3, unconjugated estriol.

Detection rate varies with gestational age, with improved detection at lower gestational ages.

Adapted from Practice bulletin no. 163: screening for fetal aneuploidy. Obstet Gynecol 2016; 127(5): e126.