Certified Medical Assistant Practice Exam

The primary purpose of using a tourniquet during venipuncture is to restrict blood flow, which helps engorge the veins, making them more prominent and easier to access for a blood draw. By temporarily occluding the venous return while allowing arterial inflow, the tourniquet causes the veins to fill with blood, resulting in a more pronounced and expanded appearance. This technique is especially useful when trying to locate veins in patients with smaller or more challenging veins, such as those seen in children or individuals with dehydration.

The other options, while related to the broader context of venipuncture and patient care, do not accurately describe the primary role of a tourniquet. Applying pressure after blood collection relates to hemostasis and not to the initial task of locating and accessing veins. Ensuring sterilization of the area is accomplished through antiseptic techniques, separate from the function of a tourniquet. Minimizing pain during the procedure can be aided by various techniques, but the tourniquet itself does not directly reduce pain; it is more focused on facilitating access to the vein.