Final answer:
The finger is the recommended site for a skin puncture in adults, providing easy access and sufficient blood flow for capillary blood samples.
Step-by-step explanation:
The recommended site for collecting a skin puncture in an adult is the finger. This is because the finger allows for easy access and sufficient blood flow for most tests requiring a capillary blood sample. The fingertip, specifically the fleshy pad of the finger, is typically used for this type of blood collection in adults, whereas heel sticks are commonly used for newborns and infants. It is important to avoid the finger for individuals with certain conditions or when looking for specific tests that require arterial blood, where other sites might be more appropriate, such as the radial artery at the wrist.