Alpha fetoprotein (AFP) is a protein produced by the liver and yolk sac of a fetus. AFP has no normal function in adults. The alpha fetoprotein test (AFP) is a blood test performed to measure, diagnose, or monitor fetal distress or fetal abnormalities. It can also detect some liver disorders and some cancers in adults.
During pregnancy, this test, along with the examination of amniotic fluid (amniocentesis), can help detect fetal spinal bifida or other defects of the fetus' neural tube.