alpha-fetoprotein

Meaning of alpha-fetoprotein: Alpha-fetoprotein is a protein made by a developing fetus, used both in prenatal screening and as a marker for certain cancers in adults.

Definition of alpha-fetoprotein

Alpha-fetoprotein is a protein normally produced by a developing fetus, primarily by the fetal liver and yolk sac. Its levels are usually very low or undetectable in the blood of adults who are not pregnant.

During pregnancy, alpha-fetoprotein crosses into the mother's bloodstream, and measuring its level is one part of prenatal screening, since unusually high or low levels can be associated with certain conditions affecting the developing fetus. In adults who are not pregnant, an elevated level can indicate certain cancers, particularly primary liver cancer or germ cell tumors of the testicle or ovary.

Because alpha-fetoprotein can rise for reasons unrelated to cancer, including pregnancy and some non-cancerous liver conditions, an elevated result is generally interpreted alongside other clinical information and imaging rather than on its own.