The quad screen test is a maternal blood screening test that looks for four specific substances: AFP, hCG, Estriol, and Inhibin-A. AFP: alpha-fetoprotein is a protein that is produced by the fetus
hCG: human chorionic gonadotropin is a hormone produced within the placenta
Estriol: estriol is an estrogen produced by both the fetus and the placenta
Inhibin-A: inhibin-A is a protein produced by the placenta and ovaries
The screen is essentially the same as the screening tests that look for only three substances, except the likelihood of identifying pregnancies at risk for Down Syndrome.
at 1:52 PM on Sep. 4, 2009