Final answer:
The tourniquet should be released after the last blood collection tube is filled, but before the needle is removed, to avoid discomfort and complications. It should not be left on for more than 1-2 minutes.
Step-by-step explanation:
The question is related to the proper protocol during the procedure of blood collection by a phlebotomist. When drawing multiple blood collection tubes, the tourniquet should be released after the last tube is filled, but before the needle is withdrawn from the vein. The correct answer would be B) After the last tube. It is important to release the tourniquet before completing the draw to minimize discomfort and potential complications such as hematoma or hemoconcentration. However, the tourniquet should not be left on for more than 1-2 minutes to prevent venous stasis and changes in blood composition that could affect test results. Hence, answer C) 1-2 minutes also has relevance in indicating the maximum time a tourniquet should be applied during blood collection, although it is not specific to the question of when to release it during the process.