What is the maximum time a tourniquet should be used during blood collection?

Using a tourniquet during blood collection is essential for making veins more prominent, which facilitates easier access for venipuncture. However, it is crucial to limit the duration of tourniquet application to prevent complications such as hemoconcentration—the process where blood components become overly concentrated due to the prolonged restriction of blood flow.

The maximum time that a tourniquet should be applied is typically around one minute. This duration strikes a balance between effectively engorging the vein and minimizing potential complications that can arise from extended application, such as discomfort for the patient, hemolysis, and changes in the chemical composition of the blood sample. When a tourniquet is left on for longer than one minute, it can compromise the quality of the blood sample, leading to inaccurate test results.

The other durations provided are either too short or excessively long for standard practice in phlebotomy. A 30-second application may not sufficiently allow for vein engorgement, while two minutes or more can cause significant adverse effects and is considered unsafe for the patient. Hence, the recommendation to use a tourniquet for no longer than one minute ensures both effective blood collection and patient safety.