What can happen if the tourniquet is left on too long before drawing blood?

Leaving a tourniquet on for an extended period before drawing blood can lead to hemoconcentration. This occurs when blood components become concentrated as plasma is forced away from the venous site due to the pressure of the tourniquet. As a result, the blood sample may have an artificially elevated concentration of certain cellular components, like red blood cells, white blood cells, and platelets, giving a skewed perspective of the patient’s true physiological state. Hemoconcentration can impact test results, making them inaccurate and potentially leading to misdiagnosis or improper treatment.

Vasodilation generally refers to the widening of blood vessels which is typically not a direct effect of prolonged tourniquet application. Hemolysis, the breaking down of red blood cells, is more likely associated with improper blood draw techniques or excessive agitation of a sample rather than the duration of a tourniquet application. Sample contamination typically arises from external sources, such as handling procedures or contamination from skin flora, and is not directly linked to the duration of tourniquet application.