What is the recommended order of draw when obtaining specimens by capillary puncture according to CLSI?

The recommended order of draw when obtaining specimens by capillary puncture is crucial to ensure the integrity of the samples and to avoid cross-contamination between different types of anticoagulants and additives. The correct choice indicates that blood gas specimens should be drawn first, followed by EDTA specimens, and then all other additive specimens, with serum specimens being drawn last.

This order is important because blood gas specimens are especially sensitive to the handling and timing of the draw. They require immediate analysis to obtain accurate results, and drawing these first minimizes the risk of contamination from other additives that might affect the results.

EDTA specimens are drawn next since EDTA is an anticoagulant that prevents clotting, and it is essential to have these samples after the blood gas to avoid any potential interference. Following these, other additive specimens are collected, which could also have various effects on the samples, so they should be drawn after the most sensitive specimens.

Drawing serum specimens last is also logical because they require clotting, and by drawing them after the other types, you reduce the risk of introducing additives that could interfere with the clotting process or sample integrity. This systematic approach is vital in clinical settings to ensure accuracy and reliability in test results.