Final answer:
If a patient reports a sharp pain radiating down their arm during a venipuncture, the PCT should stop the procedure and inform the nurse.
Step-by-step explanation:
If a patient reports a sharp pain radiating down their arm during a venipuncture, the appropriate action for the Phlebotomy Technician (PCT) to take would be to stop the procedure and inform the nurse. Sharp pain radiating down the arm during a venipuncture could be an indication of a complication, such as nerve damage, and requires further evaluation by a healthcare professional. Continuing with the venipuncture or applying more pressure to the needle site could potentially worsen the situation and cause harm to the patient.