What can result from leaving a tourniquet in place for too long during venipuncture?

Leaving a tourniquet in place for an extended period during venipuncture can lead to hemolysis of blood samples. When a tourniquet is applied, it creates a temporary occlusion of blood flow in the vein, which can cause the blood cells to become overly concentrated. Prolonged pressure on the vein can also lead to the rupture or lysis of red blood cells, resulting in hemolysis. This can significantly affect the sample's accuracy and the results of various blood tests, as hemolysis can release intracellular contents into the serum, skewing the values for parameters such as potassium, bilirubin, and enzymes.

In contrast, leaving a tourniquet on will not improve blood flow; actually, it restricts it. While increased venous pressure can occur with prolonged application, it does not directly lead to the same immediate complications seen with hemolysis. Formation of scar tissue is a long-term consequence of repeated venipuncture over time, rather than a direct result of a tourniquet being left on too long during a single procedure. Thus, the potential for hemolysis stands out as the most critical and immediate concern in this context.