Alpha-Fetoprotein (AFP) in Blood

AFP (Alpha-Fetoprotein) Test, MSAFP (Maternal Serum Alpha-Fetoprotein) Test

What To Think About

• The level of AFP in the blood is often used in a maternal serum triple or quadruple screening test. Usually 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), beta human chorionic gonadotropin (beta-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. For more information about estriol and hCG, see the medical tests Estrogens, Human Chorionic Gonadotropin (hCG), and Hormone Inhibin A.
• AFP is a screening test to look for possible problems in your unborn baby. Other tests must always be done if the AFP results are abnormal. An ultrasound will likely be done if the AFP is abnormal. If an ultrasound cannot find the cause of the abnormal AFP, an amniocentesis may be recommended. For more information, see the medical test Fetal Ultrasound.
• A normal AFP result does not mean a neural tube defect or Down syndrome is not present.
• The amount of AFP in the amniotic fluid may also be measured using amniocentesis. Most women have normal AFP levels in the amniotic fluid, even though the levels may be abnormal in their blood. These women are at low risk of having a fetus with a neural tube defect. For more information, see the medical test Amniocentesis.
• If abnormal levels of AFP are found, talk with your doctor or a genetic counselor. AFP test results can be abnormal, even when nothing is wrong with the baby.
• In people with liver cancer or other types of cancer, a decrease in AFP may mean treatment is working.

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Author:	Jan Nissl, RN, BS	Last Updated May 29, 2006
Medical Review:	Renée M. Crichlow, MD - Family Medicine Siobhan M. Dolan, MD, MPH - Reproductive Genetics
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