Which risk is associated with improper blood collection technique?

Hematoma formation at the puncture site is a recognized risk associated with improper blood collection technique. When a vein is punctured incorrectly, especially if the needle is inserted at an improper angle or if excessive pressure is applied, blood can leak out of the vessel and accumulate in the surrounding tissue. This accumulation results in a hematoma, which can cause swelling, pain, and bruising.

The other choices do not represent risks associated with improper blood collection techniques. For instance, an increased venipuncture success rate suggests a high proficiency in the technique, rather than a risk. Similarly, a reduction of pain during the procedure and improved sample quality imply that the procedure is being performed correctly and skillfully, which is contrary to the concept of improper technique. Thus, hematoma formation reflects a tangible and common consequence of poor practice in blood collection.