Medical necessity: making sense out of nonsense.

Series Editor's Note: Medical necessity, a concept that is hard to define and frequently misunderstood, has become critical to how health care is financed and delivered. Like most physicians, I believe that I have reasonable judgment as to what is medically necessary for my patients. I also understand that at times some of my patients have different ideas regarding what is necessary for their medical care. From the perspective of third party health insurance, however, medical necessity is a specific legal and contractual term that has come to be used to determine what health care benefits are covered, who pays for them, and who makes these decisions. As a re-