Which finger should a medical assistant choose for performing a capillary puncture on an adult?

• A. Index finger
• B. Middle finger
• C. Ring finger
• D. Pinky finger

Answer: (B)

For performing a capillary puncture on an adult, the middle finger is the preferred choice due to its anatomy and blood supply. The middle finger has a sufficient amount of blood supply that allows for a quick and effective puncture, providing a reliable sample without excessive tissue damage. Additionally, the skin on the middle finger is typically thicker and tougher than that of the ring or pinky fingers, making it less prone to complications, such as excessive bleeding or pain during the technique.

In contrast, while the index finger can also be used, it is often used for other tasks and may have a higher risk of contamination. The ring and pinky fingers generally do not have as much blood flow and may not yield as effective a sample as the middle finger. Thus, the choice of the middle finger aligns with best practices for achieving a successful capillary puncture.