Alpha-fetoprotein (AFP) tumor marker test

This page was reviewed under our medical and editorial policy by

Bradford Tan, MD, Chair, Department of Pathology and Laboratory Medicine, City of Hope Atlanta, Chicago and Phoenix

This page was updated on June 7, 2023.

Alpha-fetoprotein (AFP) is a tumor marker used to detect and diagnose certain cancers and liver diseases. AFP blood testing may also be performed during pregnancy to determine a baby's risk for a congenital disability or genetic disorder.

AFP testing in conjunction with ultrasonography is used to screen high-risk patients for hepatocellular carcinoma. AFP testing alone isn’t used for diagnostic purposes. Instead, it’s combined with other tests to get a fuller picture of the patient’s condition. The testing may also be done as a baseline measurement once a diagnosis has been made.

While elevated AFP levels may indicate a serious health condition, most people have small amounts of AFP in their bodies. People with liver disease or certain cancers or who are pregnant have more of the marker in their blood.

An elevated AFP level isn’t an absolute indication of a severe health problem—some people have elevated AFP levels naturally.

This overview will cover the basic facts about AFP tumor marker testing, including:

What is an AFP tumor marker test used for?

The AFP tumor marker test is typically used to confirm a diagnosis and monitor cancer treatment. Oncologists may request an AFP tumor marker test if they suspect a tumor that produces AFP, such as liver and germ cell tumors. Germ cell tumors are tumors that form from reproductive (germ) cells, such as the ovaries or testicles.

AFP testing may be requested to help diagnose liver or germ cell tumors, or to see how treatments are working. Chronic liver conditions, such as liver cirrhosis or hepatitis, may be monitored with AFP testing. While AFP testing is useful, its accuracy for diagnosis may be improved when used with Dickkopf-1 (DKK-1) biomarker testing.

AFP level evaluations in pregnant women may be used to screen for potential birth defects. AFP levels increase during pregnancy, from about 14 weeks until 32 weeks of gestation. Considerations in gestational age, race, weight and age are taken into account when evaluating AFP levels as a screening test.

AFP tumor marker normal range

AFP is measured in nanograms per milliliter (ng/mL), with normal levels less than 20 ng/mL. Levels above 400 ng/mL may indicate a liver tumor or other cancer.

Elevated levels of AFP may indicate cancer of the liver, ovaries or testicles, but that isn't always the case. For example, liver diseases or liver injuries aren’t cancerous, yet they result in higher than normal AFP levels.

Understanding test results

AFP testing is sometimes performed in conjunction with additional tumor marker testing, including beta-human chorionic gonadotropin (bHCG) and lactate dehydrogenase (LDH), to clinically manage testicular germ cell tumors. These biomarkers help doctors and patients during diagnosis, cancer staging, metastasis analysis, treatment monitoring and relapse detection. AFP testing may be performed to assess treatment response and as part of ongoing surveillance.

When AFP testing is used to monitor tumors, health care providers may evaluate AFP levels to determine whether treatment is working or whether different options should be considered. For example, AFP level measurements have been useful in predicting whether advanced gastric cancer can be managed with elevated serum AFP.

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