Medical necessity is a legal concept which refers to the health care services or products provided by a physician to a patient. It is provided for the purpose of preventing, diagnosing, treating an injury or disease in accordance with generally accepted standards of medical practice. Health insurance contracts contain agreements to provide medically necessary diagnostic and treatment services. Generally, insurers will not pay for treatment unless they consider it to be medically necessary.
Medicare defines "medical necessity" as services or items reasonable and necessary for the diagnosis or treatment of illness or injury or to improve the functioning of a malformed body member.
The following is an example of a State Statute (California) on medical necessity:
Cal Wel & Inst Code § 14059.5. "Medically necessary" or "medical necessity"
A service is "medically necessary" or a "medical necessity" when it is reasonable and necessary to protect life, to prevent significant illness or significant disability, or to alleviate severe pain.
This definition represents a legislative judgment that the medical services provided be restricted to those cases where they are most needed. [Holmes v. Kizer, 11 Cal. App. 4th 395, 402 (Cal. Ct. App. 1992)]
A stairway chair lift qualifies as "medical" equipment under this definition because it prevents significant disability, and is reasonable and necessary to protect life or prevent injury such as the injury Blue suffered while attempting to use the stairs without a chair lift. [Blue v. Bonta, 99 Cal. App. 4th 980, 989 (Cal. Ct. App. 2002)]