An Idaho Advance Directive is a revisable set of written instructions about future medical care that take effect in cases when a patient becomes unable to make decisions for themselves. The purpose of the form is to let an individual plan their medical treatment in advance.
The form lists decisions on life-sustaining medical procedures and about the specific kinds of treatment the individual may or may not wish to receive and can be used to elect a spouse, relative, friend or attorney as a decision-maker in case the individual is unable to make their own decisions because of an illness, accident or incapacity. The main difference between this form and an Idaho Living Will is that a Living Will - also called a "directive to physicians" - is one form of the Advance Health Care Directive. It's more limited in nature and only state a patient's wishes for end-of-life medical care.
An Idaho Advance Directive is defined by Section 39-4502 and regulated by Chapter 45 of the Idaho Statutes. It is advised - but not necessary - to have the document signed by at least one witness.