Question
What does AFP testing refer to in the context of Down syndrome screening?
Answer
One method of screening for Down syndrome is through the detection of the concentrations of alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCG) in maternal serum to assess the risk of carrying a fetus with Down syndrome. AFP is a specific globulin from the fetus, primarily derived from the liver and digestive tract, while HCG comes mainly from the placenta. The measurement of AFP and HCG concentrations in maternal serum, combined with the due date, age, and gestational weeks of the pregnant woman, can be used to calculate the risk coefficient for carrying a fetus with Down syndrome. Typically, pregnant women carrying a fetus with Down syndrome have lower AFP concentrations in their serum than normal pregnant women. However, a single result cannot confirm a diagnosis; all test results and indicators need to be considered comprehensively. It is recommended to have regular check-ups and follow the doctor’s advice.