NHA Phlebotomy Certification Practice Exam

What is the main purpose of using tourniquets during venipuncture?

1. To sterilize the site

2. To increase venous pressure

3. To minimize pain

4. To reduce needle stick injuries

The correct answer is: To increase venous pressure

The main purpose of using tourniquets during venipuncture is to increase venous pressure. When a tourniquet is applied to the upper arm, it temporarily restricts the flow of blood from the veins. This causes the veins below the tourniquet to become engorged with blood, making them more prominent and easier to locate. Increased venous pressure allows the phlebotomist to visualize and palpate the veins more effectively, which is crucial for a successful blood draw. By making the veins fuller and more accessible, the tourniquet enhances the chances of a clean and efficient venipuncture. This is particularly important for patients with smaller or deeper veins, as it facilitates the process and reduces the likelihood of complications during the procedure. While there could be other reasons for using a tourniquet in a clinical setting, the primary function is to enhance the visibility and accessibility of the veins by increasing venous pressure, which directly assists in the venipuncture process.