Which of the following tests on maternal serum is most useful in distinguishing between open neural tube defects and ventral wall defects in a fetus?: (A) Carcinoembryogenic antigen, (B) Sphingomyelin, (C) Alpha-feto protein, (D) Pseudocholinesterase
Answer is D. In patients with elevated amniotic fluid AFP to differentiate between NTD and abdominal wall defect, acetylcholinesterase and pseudocholinesterase are measured: