Final answer:
Applying a tourniquet for longer than a minute increases the concentration of large molecules in blood, may cause premature clotting in red top tubes, and should be differentiated from a blood pressure measurement procedure. Prolonged tourniquet time does not decrease pain or limit contamination in blood cultures.
Step-by-step explanation:
The application of a tourniquet on a patient's arm for longer than one minute can potentially lead to a variety of complications in the process of blood collection and analysis. One such issue is an increase in the concentration of large molecules, such as proteins and cells that become more concentrated due to restricted blood flow. This can affect the accuracy of certain blood tests by skewing the results. The use of a blood pressure cuff and a stethoscope in the measurement of blood pressure involves inflating the cuff to temporarily stop blood flow, which is a different procedure from the one intended for blood sample collection where the cuff should not be applied for extended periods.
A clotted sample in the red top tubes may also occur, as these tubes typically contain clot activators and the prolonged tourniquet time can lead to premature clotting of the sample. When collecting a blood sample, a lab technician must allow the blood to clot naturally in a glass tube, usually within an hour, to separate the serum for analysis. Moreover, when a patient faces a situation like severe bleeding from traumatic injuries, the body initiates a positive feedback loop involving the release of substances to promote blood clotting, an important life-saving mechanism.