1. In the Medicare program, billing for medical services provided by an employee of a provider who is a nurse, physician’s assistant, anesthetist, psychologist, technician, occupational therapist, or physical therapist. The services and supplies must be furnished under the direct supervision of the physician or other practitioner. The physician or other practitioner directly supervising the auxiliary personnel need not be the same physician or other practitioner on whose professional service the incident-to service is based. The physician does not need to be physically in the room with the ancillary provider, but he or she must be available in the immediate office suite. 2. Incident-to billing excludes inpatient hospital billing. Many hospital outpatient services need the presence and monitoring of a physician and contain incident-to language. Physicians must be in the same building when incident-to services are given by qualified providers, so physicians may need to sign in and out of a log book to document when they are on and off site. 3. Third-party payers may or may not recognize incident-to billing, and each insurance carrier has its own policies about it.