Why are needles smaller than 23 gauge generally not recommended for drawing blood?

Needles smaller than 23 gauge are generally not recommended for drawing blood primarily because they can cause hemolysis. Hemolysis refers to the breaking down or destruction of red blood cells, which can lead to inaccurate test results and complications during blood sample collection. Smaller gauge needles create a higher resistance to blood flow, which can cause turbulence and shear stress on red blood cells as they pass through the needle. This can rupture the cells, leading to a hemolyzed sample that is unsuitable for many types of laboratory tests.

Using a larger gauge needle helps ensure smoother blood flow, minimizing the risk of damaging cells while still allowing for an effective and efficient blood draw. This fundamental understanding is crucial for phlebotomists as they aim to collect quality specimens for diagnostic purposes.