American Society for Clinical Pathology (ASCP) Histotechnician Certification Practice Exam

What is the purpose of applying a tourniquet during venipuncture?

1. To constrict blood flow for easier access

2. To minimize pain during the procedure

3. To disinfect the area before puncturing

4. To prevent fainting in patients

The correct answer is: To constrict blood flow for easier access

Applying a tourniquet during venipuncture serves the primary purpose of constricting blood flow to the veins in the arm, which makes them more prominent and easier to access for needle insertion. By briefly slowing down venous blood return to the heart, the tourniquet causes the veins to distend, helping the healthcare professional locate a suitable vein for the procedure. This is particularly important in individuals with smaller or more difficult veins, as it can significantly improve the chance of a successful draw on the first attempt. The other options represent actions or concerns that are not directly related to the specific mechanical function of the tourniquet. While minimizing pain, disinfection, and preventing fainting are important aspects of venipuncture, the application of the tourniquet specifically targets improving access to the vein for blood collection.