ALPHA FETOPROTEIN ( AFP )

An AFP (alpha-fetoprotein) tumor marker test measures AFP in your blood.

Alpha-Fetoprotein (AFP) Test

What is an Alpha-fetoprotein (AFP) Test?

An AFP test is a test that is mainly used to measure the level of alpha-fetoprotein (AFP) in the blood of a pregnant person. The test checks the baby's risk for having certain genetic problems and birth defects. An AFP test is usually done between 15 and 20 weeks of pregnancy.

AFP is a protein that a developing baby makes. Normally, some AFP passes from the baby into the pregnant person's blood. Certain conditions can make a baby's body release more or less AFP. During pregnancy, if your AFP blood levels are higher or lower than normal, it may be sign that:

• The baby has a high risk of having a genetic disorder, such as:
  • A neural tube defect, which is a serious condition that causes abnormal development of a developing baby's brain and/or spine.
  • Down syndrome, a genetic disorder that causes intellectual disabilities and other health problems.
• Your estimated due date is wrong. AFP levels normally rise and fall at set times during pregnancy, so an abnormal AFP may mean that your baby is due earlier or later than estimated. This is the most common reason for abnormal AFP levels.
• You're pregnant with more than one baby. Each baby makes AFP, so your AFP blood levels will be higher with two or more babies.

Other names: AFP Maternal; Maternal Serum AFP; msAFP screen

What is it used for?

An AFP blood test is used during pregnancy to check the baby's risk of birth defects and genetic disorders, such as neural tube defects or Down syndrome. The test does not diagnose any health conditions. If your AFP test results aren't normal, it means you need more testing to find out whether your baby has a health problem.

For people who aren't pregnant, an AFP test may be used to help diagnose certain cancers that may cause high AFP levels in adults. When the test is used this way, it's called an AFP tumor marker test.

Why do I need an AFP test?

If you are pregnant, AFP test is routinely offered between the 15th and 20th week of pregnancy. Your provider may especially recommend the test if you:

• Have a family history of birth defects
• Are 35 years or older
• Have diabetes
• Have used medicines or drugs during pregnancy that could harm the baby

What happens during an AFP test?

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.