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 3 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 germ cell tumors of the testicles or ovaries, 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. AFP is also higher in people with the rare genetic condition ataxia-telangiectasia.
You may need this test if your healthcare provider thinks you may have liver cancer, testicular cancer, or cancers of the brain, mediastinum (chest), or blood.
This test is also used to track cancer treatment, or see if cancer has come back after treatment.
If your healthcare provider thinks you may have liver cancer, you may also have tests such as:
Liver function tests (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 (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 the level of 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. Blood chemistry tests check the levels of certain substances in your blood, such as calcium, potassium, and glucose. For example, your blood calcium and cholesterol levels can rise when you have liver cancer, whereas your glucose level may fall.
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 (hCG)
Lactate dehydrogenase (LDH)
Your healthcare provider also is likely to order imaging tests, such as ultrasound, CT scan, or MRI, or a biopsy to check for different cancers.
Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.
AFP is measured in nanograms per milliliter (ng/mL). An AFP level between 0 ng/mL to 40 ng/mL is normal for adults. An extremely high level of AFP in your blood—greater than 400 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.
The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand.
Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore.
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.
You don't need to prepare for this test. Be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any street drugs you may use.