What is alpha-fetoprotein (AFP) blood test?
The most abundant plasma protein found in the human fetus is alpha-fetoprotein (AFP). AFP is a protein normally made by the immature liver cells in the fetus. At birth, infants have relatively high levels of AFP, which fall to normal adult levels by the first year of life. Also, pregnant women carrying babies with neural tube defects may have high levels of AFP in both the bloodstream and in the amniotic fluid. A neural tube defect is an abnormal fetal brain or spinal cord that is caused by folic acid deficiency during pregnancy. The test requires a blood sample.
In which situations are high blood levels of AFP seen in adults?
In adults, high blood levels (over 500 nanograms/milliliter [or ng/ml]) of AFP are seen in only a few situations:
- Hepatocellular carcinoma (HCC)
- Germ cell tumors (cancer of the testes and ovaries)
- Ataxia telangiectasia