What Can an AFP Tumor Marker Test Tell Me?

Usually, you have a very small amount of alpha-fetoprotein (AFP) in your body. But when you have liver disease, some types of cancer, or are pregnant, you'll usually have more of it in your blood. An AFP tumor marker test checks the level of this protein.

A higher AFP level doesn't always mean you have a health problem. Some people simply have more AFP than is typical.

Why You Get Tested

Your doctor may want you to have an AFP tumor marker blood test to:

  • Narrow down the cause of a lump in your liver, testicles, or ovaries
  • Help decide the best treatment for cancer
  • See how well a cancer treatment is working
  • Make sure cancer hasn't come back after treatment

AFP tests can also check for birth defects in an unborn baby. Doctors may test spinal fluid for AFP, too, depending on what they're looking for.

How It's Done

You can have an AFP blood test at your doctor's office or in a hospital. A technician will use a needle to take a sample from a vein in your hand or arm. You may feel a small prick and have a little bleeding or bruising where the needle goes in.

Then they'll send your blood to a lab.

What the Results Mean

Doctors measure AFP in your blood in nanograms per milliliter (ng/mL). The normal level for most healthy adults is between 0 and 8 ng/mL.

Many things, including cancer, liver diseases like hepatitis and cirrhosis, as well as an injured liver that's healing, can raise that number. You'll likely need more tests to get the right diagnosis.

Very high levels -- 500 to 1,000 ng/mL or more -- are often a sign of certain kinds of cancer. Other types of cancer may not show up on an AFP test.

When you have liver disease already, an AFP of more than 200 ng/mL usually means you have liver cancer.

AFP-L3% Test

For people who have a raised AFP but less than 200 ng/mL, the doctor may want to do an AFP-L3% test (also called L3AFP). This compares the amount of a specific kind of AFP (AFP-L3) to the total amount of AFP in your blood. It helps doctors figure out what's going on, especially when you have a chronic liver disease, like cirrhosis.

An AFP-L3% result of 10% or more suggests that you have higher odds of getting liver cancer and your doctor should watch carefully for signs of it.

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After Diagnosis

These tests can also help your doctor check how well your cancer treatment is working. Ideally, you want to get back to a normal level.

Regular AFP tests can help catch a relapse early, too. If the cancer you had before comes back, your AFP level will go up, sometimes before you have any symptoms.

WebMD Medical Reference Reviewed by Neha Pathak, MD on November 25, 2017

Sources

SOURCES:

University of Rochester Medical Center: "Alpha-Fetoprotein Tumor Marker (Blood)."

National Center for Biotechnology Information: "Gene: AFP alpha fetoprotein [Homo sapiens (human)]."

LabTestsOnline.org: "AFP Tumor Markers," "Second Trimester Maternal Serum Screening."

Open Access Journal of Urology: "Role of biochemical markers in testicular cancer: diagnosis, staging, and surveillance."

American Cancer Society: "Tests for Liver Cancer."

National Cancer Institute: "Tumor Markers."

Mayo Medical Laboratories: "Test ID: AFPSF -- Alpha-Fetoprotein (AFP), Spinal Fluid," "Test ID: L3AFP -- Alpha-Fetoprotein (AFP) L3% and Total, Hepatocellular Carcinoma Tumor Marker, Serum."

American Pregnancy Association: "Maternal Serum Alpha-Fetoprotein Screening (MSAFP)."

ClinLab Navigator: "Alpha Fetoprotein Tumor Marker."

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