The Quadruple Test is a screening test performed during pregnancy to assess the risk of certain fetal abnormalities including Down syndrome. It measures four different hormones in the mothers blood including Alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), unconjugated estriol (uE3), and inhibin A. The test is performed by drawing a sample of blood from the mother between 15-20 weeks of pregnancy. The results of the test are used to determine the likelihood of a fetal abnormality and may lead to further testing or intervention.