The Alpha-Fetoprotein (AFP) test measures the amount of AFP, a major protein produced primarily by the yolk sac and the liver of a developing fetus. Normally, AFP levels are high in a pregnant woman's blood and the amniotic fluid, but they drop rapidly after birth.
In adults, elevated AFP levels are most commonly used as a tumor marker to help diagnose and monitor certain cancers, most notably liver cancer and certain germ cell tumors (cancers of the testes or ovaries).
