Alpha Fetoprotein (AFP) Tumor Marker Test

What is an AFP (alpha-fetoprotein) tumor marker test?

An AFP tumor marker test is a blood test that measures the level of AFP (alpha-fetoprotein) in a sample of your blood. AFP is a protein that the liver makes when its cells are growing and dividing to make new cells. AFP levels are normally high in a fetus, but after birth, they drop very low. Healthy children and adults who aren’t pregnant have very little AFP in their blood.

If you aren’t pregnant, AFP is mainly measured as a tumor marker. Tumor markers are substances made by cancer cells or by normal cells in response to cancer. High levels of AFP can be a sign of cancer of the: 

• Liver (hepatocellular carcinoma,or HCC).
• Ovaries (germ cell tumors). 
• Testicles (nonseminomatousgerm cell tumors). 

However, some people who have liver, ovarian, or testicular cancer can have normal AFP levels. This is because not all tumors produce high levels of this tumor marker. High AFP levels can also be caused by noncancerous conditions that affect the liver, such as: 

• Cirrhosis (scarring of the liver).
• Chronic hepatitis B or hepatitis C infections. 
• Liver disease. 

Because high levels of AFP don’t always mean cancer, health care providers don’t use the results from an AFP test alone to screen for or diagnose cancer. 

Other names: total AFP, alpha-fetoprotein-L3 Percent

What is it used for?

Though an AFP tumor marker test alone cannot be used to screen for or diagnose cancer, it can be used alongside other tumor marker and imaging tests, such as: 

• Ultrasound, a test that uses sound waves to make pictures of organs, tissues, and other structures inside your body. 
• Computed tomography (CT), a test that uses special x-ray equipment to make cross-sectional pictures of your body. 
• Magnetic resonance imaging (MRI), a test that uses a large magnet and radio waves to look at organs and structures inside your body. 
• PIVKA-II test, which measures the amount of a protein in your blood that can rise when the liver isn’t working well. High levels may mean the liver has trouble making normal clotting factors. Providers can use this test along with an AFP test to help detect liver cancer (HCC).
• AFP-L3% test, which measures the amount of a specific type of AFP called L3. This test compares the amount of L3 to the amount of total AFP in your blood. If the portion of L3 increases, it may mean you have a high risk of developing HCC. Providers often use this test to check the risk of liver cancer in people who have chronic liver disease.

An AFP tumor marker test may also be used to: 

• Monitor certain types of cancer and cancer treatment. AFP levels often go up as tumors grow and go down as they shrink. Your provider may test you regularly during treatment to check how well it’s working. 
• Help make a prognosis (predict how cancer may behave over time). AFP levels can help your provider understand how advanced your cancer is, how fast it might grow, and how likely it is to respond to treatment. 
• Check whether cancer has returned after treatment. AFP levels sometimes rise before symptoms appear, so your provider may use this test to check if any cancer has returned. 
• Monitor chronic liver diseases. In people with cirrhosis or chronic hepatitis B or C, AFP testing may be used with a liver ultrasound every six months to help detect liver cancer early. 

Why do I need an AFP tumor marker test?

You may need an AFP tumor marker test if you:

• Have been diagnosed with liver, ovarian, or testicular cancer.
• Are being treated for a cancer that causes high AFP levels. Measuring your AFP levels can show how well your treatment is working.
• Have completed treatment for a cancer that increased your AFP level. You may need an AFP tumor marker test from time to time to check whether your cancer is coming back.

If you have chronic hepatitis or cirrhosis, you have a higher risk of developing liver cancer. A very high level of AFP or a sudden increase can be an early sign of liver cancer. Because of this, some providers may still use an AFP tumor marker test along with other blood and imaging tests to watch for liver cancer.

Your provider may also order this test if you have symptoms of liver or germ cell cancers, such as abdominal (belly) pain or swelling, jaundice (yellowing of the skin and eyes), or a lump or swelling in the testicles.

What happens during an AFP tumor marker 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.

Will I need to do anything to prepare for the test?

You don't need any special preparations for an AFP tumor marker test.

Are there any risks to the test?

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

If you haven’t been diagnosed with cancer, test results that show:

• High levels of AFP may be a sign of cancer of the liver, ovaries, or testicles. However, high levels could also be a sign of liver injury and liver diseases that aren’t cancer. Less often, high levels of AFP may be a sign of other cancers, including lymphoma or lung cancer. Your provider will use your medical history and other test results to make a diagnosis.
• Normal levels of AFP mean you’re less likely to have a cancer that causes high AFP levels. But a normal test result doesn’t rule out cancer because some people with these cancers have normal AFP levels.

If you’re being treated for a cancer that increased your AFP levels, you may be tested several times during treatment. Your provider will look at all your AFP test results to see how your levels have changed over time. If your results show:

• Your AFP levels are increasing, it may mean that your treatment isn’t working.
• Your AFP levels are decreasing, it may mean your treatment is working.
• Your AFP levels have stayed the same, it may mean your disease is stable and hasn’t gotten better or worse.

If you’ve finished treatment for cancer that caused high AFP levels and your test results are:

• Not normal, it may mean that you still have some cancer in your body.
• Higher now than they were shortly after treatment, it may mean your cancer is growing again.

If you have a long-lasting liver disease that’s not cancer, you may need other tests to check for liver cancer if your test results show a sudden increase in AFP or your level is very high.

Ask your provider to explain what your test results mean for your health.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about an AFP tumor marker test?

You may have heard of another type of AFP test that’s used during pregnancy. This test measures total AFP levels in the blood, but it’s not a tumor marker test for cancer. It’s used to check for the risk of certain birth defects in a fetus.