At what gestational age should MSAFP be collected?

The correct timing for collecting maternal serum alpha-fetoprotein (MSAFP) is during the period of 16 to 22 weeks of gestation. During this window, the levels of MSAFP can provide valuable information regarding fetal development, particularly in assessing the risk of certain congenital anomalies, such as neural tube defects and abdominal wall defects.

When MSAFP is measured in this timeframe, it reflects the alpha-fetoprotein produced by the fetus and is at appropriate levels to interpret the results in conjunction with other markers or ultrasound findings. Testing done before 16 weeks may yield falsely low levels due to the early developmental stage of the fetus, while testing after 22 weeks may also affect the interpretation of results due to the natural decline in MSAFP levels as the pregnancy progresses. Therefore, the recommended gestational age for MSAFP collection ensures optimal accuracy in screening for potential fetal abnormalities.