Final answer:
The patient indicating implied consent for venipuncture would typically present their arm or otherwise non-verbally comply with the phlebotomist's instructions for the blood draw.
Step-by-step explanation:
The patient’s action that indicates implied consent for the venipuncture could be as simple as presenting their arm in response to the phlebotomist’s instruction or acknowledging the procedure about to take place without objection. Implied consent in this context assumes that the patient understands the procedure they are undergoing, which is part of the routine care for which they signed a general informed consent upon admission. However, if a patient clearly communicates refusal or physical resistance, this would negate implied consent, and the phlebotomist should not proceed with the venipuncture.