The basic vehicle for an adult to delegate his or her right to consent to medical care is the power of attorney to consent to medical care. In the simplest case, the person delegates all medical decision-making power to another competent adult, for a fixed period of time or an indefinite period. A competent patient may always revoke a power of attorney to consent to medical care.

Few states have laws forbidding the use of a power of attorney to delegate the right to consent to medical care. Conversely, some states do not specifically outline what a power of attorney may be used for. Although the U.S. Supreme Court has not ruled that the right to delegate medical decision making is protected by the Constitution, it has endorsed the use of powers of attorney to consent to medical care. In the absence of a specific state law or state court decision forbidding the use of a power of attorney to delegate the right to consent to medical care, this is a valid method of proxy consent for adults.

The person making the delegation must be legally and medically competent at the time the power of attorney is signed. These documents are usually notarized, but the notarization has little legal significance. The notary public may testify only as to the signer’s identity, not the person’s competency. If the person delegating the power to consent to medical care has a condition that might affect his or her competency, a physician, preferably not the patient’s usual attending physician, should evaluate the patient and swear to the patient’s competence. This should be incorporated into the power of attorney to forestall attacks on its validity. The person to whom the right to consent has been delegated must be medically and legally competent to exercise this right. If he or she is not competent, the patient must be informed and asked to appoint a new person to consent to care. If both the patient and the person to whom the right to consent has been delegated are incompetent, then a court order must be sought to determine who is legally able to consent to the patient’s care. The patient may appoint an alternate decision maker in the power of attorney and may specify under what conditions this person will serve.