AFP Test or Alpha-fetoprotein test is conducted on pregnant women to check the AFP level in the blood. The liver in the fetus produces AFP naturally. Determining the amount of AFP in the mother's blood will help identify any neural tube defect in the fetus. Neural tube defects arise in 2 out of every 1,000 pregnancies. AFP test also helps check for Down's syndrome. There are 60% chances for detecting Down's syndrome when the AFP levels are low in the blood. AFP can also be calculated from the sample of amniotic fluid of a pregnant woman. This screening test is generally performed between 16 and 18 weeks of pregnancy and is very sensitive between 15 and 17 weeks. The accuracy of the AFP test result lies in the exact age of the fetus. The AFT test is also referred to as maternal serum alpha-fetoprotein (MSAFP). AFP test is done on men and non-pregnant women too to confirm cancer in the testicles, stomach, pancreas, liver and the ovaries. High levels of AFP can indicate renal cell cancer.
Interpretation of AFP test results: In men and non-pregnant women, the values of the AFP test is 0-6.4 IU/mL (international units per milliliter), 0-20 nanograms per milliliter (ng/mL) or 0-20 micrograms per liter. In pregnant women of about 15 - 22 weeks gestation, the AFP results usually show 19-75 IU/mL, 7-124 ng/mL or 7-124 microgram per liter. AFP test values vary depending on the weight of the woman and race. Black women have higher values than white women and white women have higher values than Asian women. High AFP can suggest multiple pregnancies, fetus with neural tube defects, and abdominal wall defect in the fetus or fetal death. In non-pregnant adults, high AFP values mean cancer in the testicles or ovaries. High AFP can also indicate liver disease and bowel inflammation.
Genetic testing is a method of genetic diagnosis to check for the susceptibility to hereditary diseases and can also be used to establish the ancestry of any person. Genetic testing studies the chromosome, breaking it to individual genes. In a broader sense, it can be used as a biochemical test for scrutinizing the existence and nonexistence of main proteins that hint abnormalities of certain genes. Genetic testing studies the abnormality in the chromosomes, genes or proteins. It can be used to find out whether a particular genetic condition is developing and it's chances of being passed over to the future generations.
The most widely used type of genetic testing is newborn screening. Genetic testing during pregnancies is called as prenatal genetic testing and is performed during pregnancy to screen or identify birth defects. This provides ample information on the developing fetus both for the parents and the physician. Amniocentesis and chorionic villus sampling is the common diagnostic test performed to diagnose any defect in the fetus. These diagnostic tests are ordered for if the triple test (AFP test, hCG blood test, and UE3) returns abnormal results.
Bibliography / Reference
Collection of Pages - Last revised Date: July 15, 2018