What is the quantity of blood required for a fetal scalp blood sample?

The appropriate quantity of blood required for a fetal scalp blood sample is 30 to 50 μL. This volume is deemed sufficient to perform the necessary laboratory evaluations, such as assessing the fetal acid-base status, which is critical in evaluating fetal well-being during labor.

A smaller sample, such as 10 to 20 μL, would not typically yield enough material for accurate and reliable testing. Conversely, a sample size of 50 to 70 μL or more than 100 μL may be excessive for the required analyses and could complicate the procedure or increase the risk of maternal or fetal complications. Therefore, the range of 30 to 50 μL is optimal, providing an adequate amount for accurate assessments without unnecessary risks.