An alpha-fetoprotein (AFP) test is a blood test used to measure levels of a protein that is naturally high in a developing fetus and decreases after birth. It serves two main purposes: as a prenatal screening tool to assess a baby’s risk for certain genetic disorders like neural tube defects, and as a tumor marker in adults to help detect and monitor specific cancers (such as liver, ovarian, or testicular) and non-cancerous liver diseases. Elevated levels in adults don’t automatically mean cancer, and the results are interpreted alongside other medical information