![alpha fetoprotein alpha fetoprotein](http://alpha-cancer.com/wp-content/uploads/hero-afp.png)
If the tube that becomes the brain and spinal cord does not close correctly during fetal development, AFP may leak through this abnormal opening and enter the amniotic fluid. These types of defects include spinal column defects ( spina bifida ) and anencephaly (a severe and usually fatal brain abnormality). The test is used as an indicator of risk and then an appropriate line of testing (such as amniocentesis or ultrasound) follows, based on the results.Ībnormally high AFP may indicate that the fetus has an increased risk of a neural tube defect, the most common and severe type of disorder associated with increased AFP. Alone, AFP screening cannot diagnose a birth defect. It is very important that the doctor know precisely how old the fetus is when the test is performed since the AFP level changes over the length of the pregnancy. By analyzing the amount of AFP found in a blood or amniotic fluid sample, doctors can determine the probability that the fetus is at risk for certain birth defects. The level of AFP can then be determined by analyzing a sample of the mother's blood. During pregnancy, the fetus excretes AFP in urine and some of the protein crosses the fetal membranes to enter the mother's blood. After birth, the infant's liver stops producing AFP, and an adult liver contains only trace amounts. The exact function of this protein is unknown. PurposeĪlpha-fetoprotein is a substance produced by the liver of a fetus. Outside pregnancy, the AFP test is used to detect liver disease, certain cancerous tumors, and to monitor the progress of cancer treatment. This screening test cannot diagnose a specific condition it only indicates increased risk for several birth defects. The level of AFP can also be determined by analyzing a sample of amniotic fluid. This screening test measures the level of AFP in the mother's blood and indicates the probability that the fetus has one of several serious birth defects. The alpha-fetoprotein (AFP) test is a blood test that is performed during pregnancy.