Alpha-Fetoprotein (AFP) Test

Alpha-Fetoprotein (AFP) Test – Overview

Alpha-fetoprotein (AFP) is a protein made by a fetus’ liver that is present in the amniotic fluid and in the mom’s bloodstream before and during pregnancy. An AFP Test measures the level of AFP in the blood. This test is usually done between 15 and 20 weeks of pregnancy, and is more accurate if performed between weeks 16 and 18. While a normal level of AFP does not mean that the baby is completely safe from any birth defects, an elevated level may suggest that further testing is required.

Why is the AFP Test Done?

The AFP Test is done to screen for neural tube defects, such as spina bifida, and abdominal wall defects (omphalocele). It can also provide information that helps give an estimate of the baby’s age in the womb and the chance of having a multiple birth pregnancy. In rare cases, the AFP test can indicate a large fetal tumor or an abnormal chromosome number, such as an extra chromosome 21 that is due to Down syndrome.

Preparation for the AFP Test

No preparation is necessary for an AFP Test. The test is taken in a clinic, a hospital or a company that specializes in testing.

Procedure of the AFP Test

The AFP Test is performed as a regular blood draw, usually from the arm. The sample will then be sent to a laboratory for analysis. Generally, the results can be available within a few days.

Types of AFP Tests

There are three types of AFP Tests available:

  • Maternal AFP Test – This test measures the amount of AFP in the mother’s blood.
  • Sonographic AFP Test – This test measures the amount of AFP in the amniotic fluid.
  • Duo AFP Test – This test is a combination of the maternal and sonographic types of the AFP test.

Risks Associated with the AFP Test

The risks associated with the AFP Test are very minimal, as it is a simple blood draw. There may be some minor discomfort or bruising at the injection site, but these side effects are rare.

When is the AFP Test Recommended?

The AFP Test is recommended to most pregnant women between the 15th and 20th week of gestation. It is used to check for birth defects that can affect the fetus. However, the test is only an indicator; it does not always indicate an actual problem.


The AFP Test is an important part of pregnancy that can help identify certain birth defects that may be present in the fetus. The test is generally recommended for all pregnant women between weeks 15 to 20. The process itself is simple and there are minimal associated risks. While the results can help indicate the likelihood of the baby having certain birth defects, it is not always a reliable indicator and additional tests may be recommended.