What is the maximum duration a tourniquet should be left on during venipuncture?

During venipuncture, the maximum duration a tourniquet should be applied is generally considered to be up to 60 seconds. This recommendation is based on the need to minimize any potential complications that can arise from prolonged tourniquet application, such as hemoconcentration, tissue ischemia, and discomfort for the patient.

When a tourniquet is applied, it temporarily restricts blood flow to the area, which can make veins more prominent and easier to access. However, if left on for too long—beyond the recommended timeframe—this can lead to a buildup of metabolic byproducts in the blood, altering the concentration of some analytes and potentially skewing test results. Keeping the duration strictly to 60 seconds helps to balance the need for a good venipuncture site with the safety and comfort of the patient.