Table 1.

Current screening tools for aneuploidy involving the use of PAPP-A

TEST	MARKERS	TRIMESTER
FTS	NT, free β-hCG, PAPP-A, MA	First
IPS	NT, PAPP-A, AFP, uE3, free β-hCG or total hCG, inhibin A, MA	First and second
IPS without inhibin A	NT, PAPP-A, AFP, uE3, total hCG, MA	First and second
Serum IPS	PAPP-A, AFP, uE3, free β-hCG or total hCG, inhibin A	First and second

AFP—α-fetoprotein, FTS—first-trimester screening, hCG—human chorionic gonadotropin, IPS—integrated prenatal screening, MA—maternal age, NT—nuchal translucency, PAPP-A—pregnancy-associated plasma protein A, uE3—unconjugated estriol.