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AFP Tumor Markers

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Also known as: AFP; Total AFP; AFP-L3%
Formal name: Alpha-fetoprotein, Total; Alpha-fetoprotein-L3 Percent

Were you looking instead for AFP Maternal, ordered during pregnancy?

The Test Sample

What is being tested?

This test measures alpha-fetoprotein (AFP) in the blood. AFP is a protein produced primarily by fetal liver and the portion of a developing embryo that is similar to the yolk cavity in bird eggs (yolk sac tissues). AFP concentrations are typically elevated when a baby is born and then decline rapidly. In healthy children and non-pregnant adults, AFP is normally only detectable at very low levels.

Liver damage and certain cancers can increase AFP concentrations significantly. AFP is produced whenever liver cells are regenerating. With chronic liver diseases, such as hepatitis and cirrhosis, AFP may be chronically elevated. Very high concentrations of AFP may be produced by certain tumors. This characteristic makes the AFP test useful as a tumor marker. Increased amounts of AFP are found in many people with a type of liver cancer called hepatocellular carcinoma and in a liver cancer occurring in infants called hepatoblastoma. They are also found in some people with cancers of the testes and ovaries.

AFP exists in several different variants. Traditionally, when a doctor orders an AFP test, it is for a total AFP, one that measures all of the AFP variants together. This is the primary AFP test in the United States.

One of the variants is called L3 because of its ability, in the laboratory, to bind to a particular protein called Lens culinaris agglutinin. The AFP-L3% test is a relatively new test that compares the amount of AFP-L3 to the total amount of AFP. An increase in the percentage of L3 is associated with increased risk of developing hepatocellular carcinoma in the near future and of having a poorer prognosis, as the L3-related cancers tend to be more aggressive. The AFP-L3% test is being ordered by a few doctors in the U.S. and is in wider use in some other countries, such as Japan.

How is the sample collected for testing?

A blood sample is taken by needle from a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.