What is the function of a tourniquet during venipuncture?

The function of a tourniquet during venipuncture is to locate veins more easily by engorging them with blood. By applying a tourniquet above the site of venipuncture, venous blood flow is temporarily restricted, causing the veins to fill with blood. This engorgement makes the veins more prominent and easier to see and palpate. Consequently, it enhances the clinician’s ability to select an appropriate site for venipuncture, which is crucial for the success of the procedure.

This method does not directly reduce pain during needle insertion, prevent blood clotting, or keep the patient from moving, as those roles pertain to different aspects of phlebotomy practice. Reducing pain would typically involve techniques such as proper needle size and patient positioning, while clotting is managed through appropriate handling and storing of blood samples post-collection. Keeping the patient still relies more on effective communication and positioning than on the use of a tourniquet. Therefore, the primary and correct function of a tourniquet in this context is its role in assisting with the visibility and accessibility of veins.