A document that appoints an individual to represent a patient's interests is called what?

The correct choice is the durable power of attorney. This document allows an individual, often referred to as the agent or attorney-in-fact, to make decisions on behalf of another person, particularly in matters such as healthcare or financial issues, when that person becomes unable to make decisions for themselves.

In the context of healthcare, a durable power of attorney specifically grants the appointed individual the authority to represent the patient's interests in medical decisions, ensuring that the patient's wishes are honored even if they cannot communicate them due to incapacitation. This legal instrument is vital in ensuring that a trusted person has the capacity to make informed decisions regarding medical treatment, end-of-life issues, and other healthcare matters.

Other options, while related, serve different purposes. An advance directive generally encompasses various directives that outline the desired medical treatment and preferences should the patient become incapacitated, but it does not appoint an individual to make decisions. A living will is a specific type of advance directive that outlines what medical treatments a patient does or does not want in specific situations but also does not assign decision-making authority to another person. A subpoena duces tecum, on the other hand, is a legal document that compels a person to produce documents or evidence in a legal proceeding, entirely unrelated to healthcare