Why is the use of tourniquets limited in time?

The use of tourniquets is limited in time primarily to prevent hemoconcentration and discomfort for the patient. When a tourniquet is applied for an extended period, it restricts blood flow to the area, which can lead to hemoconcentration. This condition occurs when the proportion of cells in the blood increases due to the plasma volume decreasing, resulting in altered test results. Additionally, prolonged application can cause discomfort or pain for the patient, which is an important consideration in phlebotomy practices. Keeping the application time short helps ensure both the integrity of the blood specimen and the comfort of the patient being treated.