Health Encyclopedia

Alpha-Fetoprotein Tumor Marker (Blood)

Does this test have other names?

AFP

What is this test?

This is a blood test to look for alpha-fetoprotein (AFP) in your blood.

AFP is normally made by a fetus's liver and yolk sac. It's the main protein during the first three months of development. AFP greatly decreases by age 1 and should only be found in adults in very low levels.

AFP is one of several tumor markers. Tumor markers are molecules in the blood that are higher when a person has certain cancers. AFP is found mainly in liver cancer and nonseminomatous germ cell tumors, which are rare. These are found in the pineal gland in the brain.

Some people with cirrhosis or chronic active hepatitis also have higher blood levels of AFP. 

Why do I need this test?

You may have this test if your health care provider suspects you have liver cancer, testicular cancer, or cancers of the brain, mediastinum, or blood.

This test is also used to watch cancer treatment or see if cancer has come back after treatment.  

What other tests might I have along with this test?

If your doctor suspects you have liver cancer, you may also have:

  • Liver function tests, or LFTs. These tests look at the part of your liver that is not affected by cancer to see how well your liver is working. The tests look for levels of certain substances in your blood, such as bilirubin, albumin, ALP, AST, ALT, and GGT.

  • Blood clotting tests. Your liver makes proteins that help your blood clot. You may have blood tests, such as prothrombin time, or PT, to find out how well your liver makes these proteins and to look at your risk of bleeding.

  • Blood urea nitrogen, or BUN, and creatinine level tests. These show how well your kidneys are working.

  • Complete blood count, or CBC. This test measures your red blood cells, white blood cells, and platelets, which help blood to clot. It also shows how well your bone marrow is working. Your marrow is where new blood cells are made. 

  • Electrolytes and blood chemistry tests. You may have your blood calcium and cholesterol levels checked because these can rise when you have liver cancer.

  • Viral hepatitis tests. Hepatitis B and C are linked to liver cancer, so you may have tests for viral hepatitis. 

You may also have tests for other tumor markers in your blood, including:

  • Human chorionic gonadotropin, or hCG

  • Lactate dehydrogenase, or LDH

Your doctor also is likely to order imaging tests such as ultrasound, CT scan, and MRI to check for different cancers. 

What do my test results mean?

Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your health care provider.

AFP is measured in nanograms per milliliter (ng/mL). An AFP level of less than 10 ng/mL is normal for adults. An extremely high level of AFP in your blood – greater than 500 ng/mL – could be a sign of liver tumors.

High levels of AFP may mean other cancers, including Hodgkin disease, lymphoma, and renal cell carcinoma (kidney cancer).

Not all people with these cancers will have an elevated AFP. And elevated AFP levels also could be a sign of cirrhosis or chronic acute hepatitis. 

How is this test done?

The test requires a blood sample, which is drawn through a needle from a vein in your arm.

Does this test pose any risks?

Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore. 

What might affect my test results?

If you are pregnant, your serum AFP level may be higher than normal. If you have hepatitis or cirrhosis, your AFP level may also be elevated.

If you had cancer and the treatment worked, your AFP levels should be normal.

How do I get ready for this test?

You don't need to prepare for this test. 



Medical Reviewers:

  • Bass, Pat F. III, MD, MPH
  • Stump-Sutliff, Kim, RN, MSN, AOCNS