Afp Prenatal Test

The AFP prenatal test is one of the tests that are used to detect the possibilities of fetal abnormalities like neural tube defects, omphalocele, and Down’s syndrome. The test is curiously also conducted on adults as well to diagnose, at a high level, the possibility of a hepatocellular carcinoma. The test is conducted either by taking maternal serum levels or by a procedure called an amniocentesis. This is a procedure in which a needle is inserted through the abdomen and guiding using ultrasound into the amniotic sac in the uterus. A small portion of the amniotic fluid is then withdrawn and tested for AFP.

AFP stands for Alpha FetoProtein. This is a fetal equivalent of human serum albumin. This albumin is a carrier protein for lipid substances and also a method of maintaining fluid volume in the body. Without this protein there would be no way of transporting lipid substances through the water-based environment of the blood stream. In fetuses, the young liver is not yet fully developed to start creating its own albumin and therefore AFP is created. Since the growing fetus also excretes directly into the amniotic sac, the levels of AFP are particularly high in the amniotic sac. High AFP levels are associated with diseases of the neural tube while low AFP corresponds with the possibility of Down’s syndrome. Neural tube defects are a particularly worrisome problem because they cause the death of the infant. The neural tube is a structure that is created from the closing of two halves just like other parts of the body. When the two halves of the neural tube close correctly, the formation of the spine and brain commence. If the two halves do not close then the fetus can carry to term without a major part of the brain, with sections fused together, be born without a neck, and even have fluid where there should be brain matter. Some neural tube defects like spina bifida can be corrected to a certain extent with fetal surgery.

Omphalocele is a condition in which the fetus develops with the intestines, liver, and other abdominal organs developing outside the abdomen. Intestines protruding outside the abdomen are sometimes normal but eventually will retreat to the peritoneal cavity. The counts of AFP should ideally be between 50 to 5 ng/mL, decreasing as the fetus grows and eventually delivers. There will always be a small amount of AFP that will remain the system.