ASCP Phlebotomy Technician Certification Practice Exam 2025 – Comprehensive All-in-One Study Guide for Success!

Using a tourniquet during venipuncture is primarily meant to engorge the veins, making them more prominent and easier to access. When a tourniquet is applied, it restricts blood flow from the site, causing the veins to fill with blood and thus become more distended. This increases the likelihood of locating a suitable vein for blood collection, especially in individuals with smaller or deeper veins.

The other responses touch on different practices that may influence the venipuncture experience but do not accurately describe the primary purpose of the tourniquet:

- Warming the site may help with blood flow, but it is not the primary function of a tourniquet.

- While preventing patient movement can contribute to a successful draw, it is not the intended use of a tourniquet.

- Minimizing pain is a goal of phlebotomy techniques in general, but the tourniquet itself does not serve to reduce pain directly; instead, it prepares the veins for access.

Thus, the correct answer reflects the fundamental role of a tourniquet in the venipuncture process.