Final answer:
If during venipuncture the patient experiences sharp radiating pain, the phlebotomist should immediately release the tourniquet and remove the needle to prevent potential nerve damage.
Step-by-step explanation:
When a patient undergoing venipuncture reports a sharp pain radiating down the arm, the correct course of action for the phlebotomist is to release the tourniquet and remove the needle immediately. This pain could indicate that a nerve has been hit or irritation has occurred, potentially leading to nerve damage if not addressed promptly.
Continuation of the procedure could exacerbate any existing injury. After the needle is removed, the site should be observed for any signs of hematoma or continued bleeding and appropriate care should be administered.