Final answer:
The maternal alpha serum protein test, or Maternal Serum Screening (MSS), is performed between 16-20 weeks of pregnancy to screen for birth defects. Elevated levels of alpha-fetoprotein (AFP) in the maternal blood may indicate the presence of a neural tube defect (NTD). Other substances measured in the test include hCG, inhibin-A, and estriol.
Step-by-step explanation:
The maternal alpha serum protein test, also known as the Maternal Serum Screening (MSS), is performed between 16-20 weeks of pregnancy for screening purposes. This test measures the levels of several substances in the mother's blood to assess the risk of certain birth defects, including neural tube defects (NTDs). Elevated levels of alpha-fetoprotein (AFP) in the maternal blood may indicate the presence of an NTD in the fetus.
Other substances that may be measured in the MSS include human chorionic gonadotropin (hCG), inhibin-A, and estriol. However, specifically for NTD screening, AFP is the primary marker.
If elevated AFP levels are detected, further diagnostic tests, such as ultrasound, are needed to confirm the presence of an NTD in the fetus.