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.
The alpha-fetoprotein test is performed on a specimen obtained via a blood draw.
Normal AFP levels for men for for non-pregnant women are less than 300 nanograms per milliliter.
Greater than normal levels of AFP may be due to:
Most "positive" AFP tests are actually false positives.
During pregnancy, increased levels of AFP may indicate:
Review Date: 7/13/2021
Reviewed By: John D. Jacobson, MD, Department of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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