What is the purpose of a tourniquet during blood collection?

The purpose of a tourniquet during blood collection is to control blood circulation, specifically by temporarily constricting blood flow in the veins. This action helps to engorge the veins to make them more visible and accessible for venipuncture, which is the process of puncturing a vein to obtain a blood sample. By applying a tourniquet about 3 to 4 inches above the intended puncture site, the phlebotomist can make it easier to locate a suitable vein and ensure that blood can be drawn more easily.

While sterilizing the puncture site is essential for preventing infection, this function is not what a tourniquet is used for. Additionally, reducing patient anxiety and providing comfort can be important aspects of patient care, but they are not direct purposes of using a tourniquet during the blood collection process. Instead, the primary and technical purpose of the tourniquet is to facilitate the successful collection of blood samples by enhancing vein visibility and accessibility.