What is the primary reason for using a tourniquet during blood draw?

Using a tourniquet during a blood draw is primarily aimed at making veins more visible. When a tourniquet is applied, it temporarily restricts venous blood flow, causing the blood to pool in the veins below the tourniquet. This pooling increases the size and visibility of the veins, making it easier for the phlebotomist to locate and access a suitable vein for the blood draw.

The visibility of veins is crucial because it allows the technician to accurately aim for a vein, which minimizes the number of attempts needed to successfully draw blood, thereby enhancing the overall patient experience and increasing the efficiency of the procedure. By ensuring that the veins are engorged, the use of a tourniquet reduces the chances of failing to find a vein on the first attempt, which can be especially beneficial in individuals with smaller or more challenging veins.

While the tourniquet may also help in the time it takes to collect a sample by facilitating a faster access to the vein, the primary and most significant function it serves is enhancing vein visibility.