When should the phlebotomist release the tourniquet during blood drawing?

The tourniquet should be released as soon as possible after blood begins to flow. This practice is important because maintaining the tourniquet too long can lead to complications such as hemoconcentration, which can affect the accuracy of test results. Releasing the tourniquet immediately after the blood flow is established helps to minimize these risks while allowing for a successful blood draw.

Releasing the tourniquet at this point also allows for continued blood flow without causing undue pressure or discomfort to the patient. Proper adherence to this practice enhances patient safety and improves the quality of the specimen being collected, ensuring that the laboratory results are reliable.

The other choices do not align with standard practices; for example, releasing the tourniquet just before inserting the needle would likely lead to a difficult blood draw, as the veins may collapse. Prior to the withdrawal of the last tube could also lead to erroneous lab results if hemoconcentration has already started to occur. Waiting five minutes after the needle removal is excessive and can compromise the integrity of the blood sample as well.