Maternal serum triple analyte screening in pregnancy.

According to the American College of Obstetricians and Gynecologists, it has become standard in prenatal care to offer screening tests for neural tube defects and genetic abnormalities. There have been some changes in the recommended method of prenatal screening over the past few years, and research to improve detection rates with better combinations of maternal serum analytes is ongoing. The issues facing physicians are the sensitivity and specificity of multiple serum analyte combinations. The current maternal serum analytes in use in most areas are alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG) and unconjugated estriol. Measurement of AFP alone can detect the vast majority of neural tube defects and a small portion of trisomy 21-affected pregnancies in patients of all ages. Adding hCG and unconjugated estriol to this screen increases the rate of detection of trisomies 21 and 18. Counseling patients about the risks and benefits of such screening is important to provide a balanced discussion of screening issues.