What is the first action the practical nurse (PN) should take when obtaining a capillary blood sample for glucose measurement?

The first action a practical nurse should take when obtaining a capillary blood sample for glucose measurement is to determine which finger was used previously. This is essential because repeated punctures on the same finger can lead to localized tissue damage, discomfort, and inaccurate blood glucose readings due to variations in blood flow. By identifying a finger that hasn't been used recently, the nurse ensures that the new puncture will yield a fresh sample without causing unnecessary trauma to the tissue.

While cleaning the puncture site with alcohol or warming the finger are important steps in preparing for the blood sample collection, such actions typically follow the determination of the site to be used. Ensuring the patient has fasted for at least 8 hours is also relevant for specific glucose testing protocols, but it is not a direct initial action related to the process of collecting a capillary blood sample; that aspect primarily concerns the timing of the test rather than the procedural steps involved in sample collection.