Alpha-Fetoprotein (AFP) In Blood: Why It Is Done

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Why It Is Done

The AFP test is done to:

• Check the unborn baby of a pregnant woman for brain or spinal problems (called neural tube defects). Such defects occur in about 2 out of every 1,000 pregnancies.² The chance of a neural tube defect in a baby is not related to the mother's age. Most women whose babies have neural tube defects have no family history of these problems. This test is done between the 15th and 22nd weeks of pregnancy.
• Check the unborn baby of a pregnant woman for Down syndrome. The chance of finding Down syndrome is about 70% when the AFP test is done with the estriol and hCG tests (triple test). The chance of finding Down syndrome increases to about 80% when the hormone inhibin A test is added (quad test).¹
• Find certain cancers, especially cancer of the testicles, ovaries, or liver. But up to half of the people with liver cancer do not have high AFP levels.
• Check how well treatment for cancer is working.
• Check for liver cancer (called hepatoma) in people who have cirrhosis or chronic hepatitis B.

Last updated:	May 14, 2008
Author:	Sandy Jocoy, RN
Reviewed By:	Sarah Marshall, MD - Family Medicine, Siobhan M. Dolan, MD, MPH - Reproductive Genetics
Editors:	Kathleen M. Ariss, MS, Tracy Landauer