WHAT IS ALPHA-FETOPROTEIN (AFP) TEST?
A globulin protein secreted by liver cells during hepatic cell multiplication and found in high amounts in fetal plasma. Highest adult amounts are found during pregnancy and in primary hepatic cancer. Maternal levels should be measured initially at 15-18 weeks of gestation as a screening method for fetal neural tube defects. Confirmatory testing (for levels greater than 0.5-2.5 times the normal median) should be repeated in 7 days. For the positive confirmatory test, ultrasonography and amniotic fluid AFP measurement should be performed. Used as a tumour marker, the AFP level is most specific when concentrations are >1000 ng/mL.