What does AFP stand for?

What Does AFP Stand For?

AFP stands for alpha-fetoprotein, a protein that plays a key role during fetal development. It’s primarily produced by the yolk sac, and later by the liver and intestines, of an unborn baby. In healthy individuals, AFP levels are high during pregnancy but drop sharply after birth. Adults typically have very low or undetectable levels in their bloodstream.

While AFP is a normal part of fetal growth, its presence in elevated amounts in older children or adults can raise medical concerns. Certain conditions, particularly some types of cancer, are associated with higher-than-normal AFP levels. For example, hepatocellular carcinoma (the most common form of liver cancer) and some germ cell tumors, like those in the testes or ovaries, can cause AFP to rise. Because of this, doctors often use AFP as a tumor marker—a tool to help diagnose, monitor, or assess treatment response in specific cancers.

It’s important to note, though, that elevated AFP doesn’t automatically mean cancer. Liver diseases such as cirrhosis or chronic hepatitis can also increase AFP levels. That’s why AFP testing is usually interpreted alongside imaging, biopsies, and other clinical data.

In prenatal care, AFP is also measured as part of maternal serum screening. Unusual levels in a pregnant woman's blood may signal potential neural tube defects or chromosomal abnormalities in the fetus, prompting further testing.

So while AFP is a small protein, its clinical significance is substantial—offering clues both in fetal health and in diagnosing certain serious conditions later in life.