What action constitutes implied consent for a venipuncture on an adult?

Implied consent for a venipuncture refers to situations where a patient's actions suggest that they consent to a procedure, even if they have not provided explicit verbal or written agreement. When a patient extends their arm towards the phlebotomist, it can be interpreted as a non-verbal cue indicating their willingness to proceed with the blood draw. This action demonstrates an understanding of the process and a readiness to participate without the need for further affirmation.

In contrast, the other options involve more explicit forms of consent. Signing a consent form is a clear indication of informed consent, while verbal agreement also establishes that the patient has explicitly accepted the procedure. Shaking hands, although socially friendly, does not communicate the specific consent needed for a medical procedure such as venipuncture. Therefore, extending an arm is a classic example of implied consent within the context of phlebotomy.