Description

An alpha-fetoprotein (AFP) test is a blood test that measures the amount of AFP present in the blood. It’s usually part of what’s called a triple screen or quad screen in the second trimester of pregnancy. However, it can also be useful for adults who aren’t pregnant. The yolk sac, GI tract, and liver of an unborn baby produce AFP. It then circulates through the fetal and maternal blood. Individuals who aren’t pregnant still have some AFP in their blood, but levels are normally low. High levels of AFP in adults who aren’t pregnant usually indicate certain types of liver disease.
Why do I need an alpha-fetoprotein test?
An AFP test is a routine screening test that’s given to expectant mothers between the 14th and 22nd weeks of their pregnancy. It is most accurate between the 16th and 18th weeks, so it’s important to know exactly when you became pregnant. AFP testing is usually part of a quad screen. This screening exam also tests your levels of:
Human chorionic gonadotropin (HCG) estriol, which is a hormone produced by your placenta and your baby’s liver
Inhibin A, which is a hormone produced by your placenta
Doctors will use your quad screen results, your age, and your ethnicity to help determine the chances that your unborn baby has a genetic birth defect. Defects detected by this type of screening can include neural tube defects, such as spina bifida, and chromosomal abnormalities, such as Down syndrome. The AFP results will help your doctor determine if you need further tests for these conditions. A positive test doesn’t necessarily mean your unborn baby will have a birth defect. The AFP test is especially important for women who are at high risk of having children with birth defects, including women:
Who is 35 or older?
With a family history of birth defects
Who used harmful medications or drugs during their pregnancies?
Who has diabetes?
If you aren’t pregnant, an AFP test can help to diagnose and monitor certain liver conditions, such as liver cancer, cirrhosis, and hepatitis. It can also help detect several other cancers, including cancers of the:
Testes
Ovaries
Biliary tract
Stomach
Pancreas