The average fee charged by a particular type of health care practitioner within a geographic area. The term is often used by medical plans as the amount of money they will approve for a specific test or procedure. If the fees are higher than the approved amount, the individual receiving the service is responsible for paying the difference. Sometimes, however, if an individual questions his or her physician about the fee, the provider will reduce the charge to the amount that the insurance company has defined as reasonable and customary.