What is an alpha-fetoprotein screening (AFP)?
Alpha-fetoprotein screening is a blood test that measures the level of alpha-fetoprotein in the mothers’ blood during pregnancy. AFP is a protein normally produced by the fetal liver and is present in the fluid surrounding the fetus (amniotic fluid), and crosses the placenta into the mother’s blood. The AFP blood test is also called MSAFP (maternal serum AFP). Abnormal levels of AFP may signal the following: • open neural tube defects (ONTD) such as spina bifida • Down syndrome • other chromosomal abnormalities • defects in the abdominal wall of the fetus • twins – more than one fetus is making the protein • a miscalculated due date, as the levels vary throughout pregnancy AFP screening may be included as one part of a two, three, or four-part screening, often called a multiple marker screen used. The other parts may include the following: • hCG – human chorionic gonadotropin hormone (a hormone produced by the placenta) • estriol – a hormone produced by the placenta. • inhibin – a horm
