Alpha Fetoprotein (AFP) Tumor Marker Test
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An AFP tumor marker test is a blood test that measures the level of AFP (alpha-fetoprotein) in a sample of your blood. It's usually used to help diagnose certain types of cancer and to check how well treatment is working. AFP is a protein that the liver makes when its cells are growing and dividing to make new cells.
AFP is normally high in unborn babies. After birth, AFP levels 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 that are often 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, ovaries or testicles.
An AFP tumor marker test cannot be used by itself to screen for or diagnose cancer. That's because other conditions can increase AFP levels, including liver diseases that aren't cancer. And some people who do have liver, ovarian, or testicular cancer will have normal AFP levels.
So, an AFP tumor marker test can't rule out cancer for sure. But when used with other tests and exams, AFP tumor marker testing can help diagnose and monitor cancers that cause high AFP levels.
Why this test is done
You may need an AFP tumor marker test if:
- A physical exam and/or other tests suggest that you may have cancer of the liver, ovaries, or testicles.
- You are currently being treated for a cancer that causes high AFP levels. Measuring your AFP test can show how well your treatment is working.
- You 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. Most medical experts don't recommend measuring AFP levels to screen for cancer in these diseases.
But, some health care providers may still use an AFP tumor marker test with other tests to watch for liver cancer.
How to prepare
You don't need any special preparations for an AFP tumor marker test.
Sample type
Blood
Other names for this test
total AFP, alpha-fetoprotein-L3 Percent
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Educational content only. This entry describes what a test measures and how published reference ranges are defined. It is not a diagnosis, does not interpret your personal results, and is not a substitute for a qualified doctor.