What is the maximum duration a tourniquet should be left on before blood flow is obtained?

The maximum duration a tourniquet should be left on before blood flow is obtained is one minute. This guideline is critical in phlebotomy because prolonged use of a tourniquet can lead to hemoconcentration, which may affect test results by increasing the concentration of certain substances in the blood while decreasing the levels of others. Leaving a tourniquet on longer than one minute can also cause discomfort or pain to the patient and may result in complications, such as the risk of petechiae or bruising. Therefore, to ensure patient safety and accurate results, it is essential to adhere to this time limit.