ABBR: AFP

An antigen present in the human fetus and in pathological conditions in the adult. The maternal serum level should be evaluated at 15 to 22 weeks' gestation. During pregnancy, elevated levels are associated with open neural tube defects, anencephaly, omphalocele, gastroschisis, and fetal death. Decreased levels may indicate an increased risk of having a baby with Down syndrome. If an abnormal level of AFP is found, further tests such as ultrasound or amniocentesis need to be done. Elevated serum levels of AFP are found in adults with hepatic carcinomas or chemical injuries. Examination results also may be abnormal in persons with diabetes, multiple pregnancies, or obesity.