Alpha-Fetoprotein (AFP) in Blood
An alpha-fetoprotein (AFP) blood test checks the level of AFP in a pregnant woman's blood. AFP is a substance made in the liver of an unborn baby (fetus). The amount of AFP in the blood of a pregnant woman can help see whether the baby may have such problems as Reference spina bifida Opens New Window and Reference anencephaly Opens New Window. An AFP test can also be done as part of a screening test to find other Reference chromosomal Opens New Window problems, such as Reference Down syndrome (trisomy 21) Opens New Window or Reference Edwards syndrome (trisomy 18) Opens New Window. An AFP test can help find an omphalocele, a congenital problem in which some of the baby's intestines stick out through the belly wall.
Normally, low levels of AFP can be found in the blood of a pregnant woman. No AFP (or only a very low level) is generally found in the blood of healthy men or healthy, nonpregnant women.
The level of AFP in the blood is used in a Reference maternal serum triple or quadruple screening test. Generally done between 15 and 20 weeks, these tests check the levels of three or four substances in a pregnant woman's blood. The triple screen checks alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and a type of estrogen (unconjugated estriol, or uE3). The quad screen checks these substances and the level of the hormone inhibin A. The levels of these substances—along with a woman's age and other factors—help the doctor estimate the chance that the baby may have certain problems or birth defects.
Screening tests are used to see what the chance is that your baby has a certain birth defect. If a screening test is positive, it means that your baby is more likely to have that birth defect and your doctor may want you to have a diagnostic test to make sure.
- Opens New Window Pregnancy: Should I Have the Maternal Serum Triple or Quadruple Test? Opens New Window
Men, nonpregnant women, and children
In men, nonpregnant women, and children, AFP in the blood can mean that certain types of cancer—especially cancer of the Reference testicles Opens New Window, Reference ovaries Opens New Window, stomach, Reference pancreas Opens New Window, or liver—are present. High levels of AFP may also be found in Reference Hodgkin's disease Opens New Window, Reference lymphoma Opens New Window, brain tumors, and renal cell cancer.
|By:||Reference Healthwise Staff||Last Revised: Reference April 4, 2012|
|Medical Review:||Reference Sarah Marshall, MD - Family Medicine
Reference Siobhan M. Dolan, MD, MPH - Reproductive Genetics