Alpha-Fetoprotein (AFP) Test Test
The alpha-fetoprotein (AFP) test is a blood test done during pregnancy to check your baby's risk of certain birth defects and genetic problems. It does not diagnose any conditions.
What this test measures
The AFP test measures the level of alpha-fetoprotein (AFP) in your blood when you are pregnant. AFP is a protein mostly made in your developing baby's liver.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Higher-than-normal results
Higher than normal AFP levels may mean your baby has an increased risk of a neural tube defect (such as spina bifida or anencephaly) or a defect in the abdomen or esophagus.
Lower-than-normal results
Lower than normal AFP levels may mean your baby has an increased risk of a genetic disorder such as Down syndrome or Edwards syndrome.
Frequently asked questions
What does the AFP test check for?
The AFP test checks your baby's risk of having certain birth defects and genetic problems, such as neural tube defects, Down syndrome, and Edwards syndrome.
When is the AFP test done during pregnancy?
The test is usually done between 15 and 20 weeks of pregnancy.
Can the AFP test diagnose a condition?
No, the AFP test cannot diagnose any conditions. It only tells you whether your baby is more or less likely to have certain problems.
What can cause abnormal AFP results besides a problem with the baby?
Abnormal results can be caused by an incorrect due date, being pregnant with more than one baby, or a false positive result.
What happens if my AFP results are abnormal?
If your results are not normal, you will likely have more tests to help find out why. Talk with your provider about your results.
Related lab tests
Sources
- MedlinePlus: Alpha-Fetoprotein (AFP) Test — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.