A nurse is teaching a client who is at 16 weeks of gestation about the alpha-fetoprotein test. Which of the following information should the nurse include in the teaching?

A. The alpha-fetoprotein test identifies a risk for ABO incompatibility: Alpha-fetoprotein (AFP) testing is not used to assess blood type compatibility. ABO incompatibility is determined through maternal and fetal blood typing and antibody screening. B. The provider will draw the alpha-fetoprotein sample from an umbilical vein: AFP is measured via maternal blood draw, not from the umbilical vein. This noninvasive maternal serum screening reduces risk to the fetus. C. The alpha-fetoprotein test screens for neural tube defects: AFP is a protein produced by the fetal liver, and abnormal maternal serum levels can indicate neural tube defects (such as spina bifida) or other fetal anomalies. This test is typically performed between 16 and 18 weeks gestation. D. The provider will collect the alpha-fetoprotein sample during an amniocentesis: While AFP can be measured in amniotic fluid, the standard screening at 16 weeks is a maternal serum AFP blood test. Amniocentesis is not routinely required for initial AFP screening.