AFP (Alpha-Fetoprotein): Prenatal Screening and Tumor Marker

Alpha-fetoprotein (AFP) is a glycoprotein produced by the fetal liver and yolk sac. In adults, low levels are produced by the liver.

Clinical Uses

• Prenatal screening (15–20 weeks): Elevated maternal serum AFP suggests open neural tube defects (spina bifida, anencephaly); low AFP associated with Down syndrome.
• Tumor marker: Elevated in hepatocellular carcinoma, germ cell tumors (testicular, ovarian).
• Liver disease: May rise in hepatitis, cirrhosis.

Interpretation requires gestational age correction and confirmatory testing (ultrasound, amniocentesis).