Patient's question:
NoDoctor's answer:
A prenatal screening test that involves drawing a pregnant woman's blood to measure the levels of alpha-fetoprotein, human chorionic gonadotropin, and free estriol in the maternal serum. By combining this information with the pregnant woman's due date, weight, age, and gestational age at the time of blood collection, the test calculates the risk factor for giving birth to a child with congenital defects.