The use of advanced practice providers (APPs): physician assistants and nurse practitioners, in the observation unit is widespread. When an OU is staffed by both physician and APPs from the same practice group and the physician provides and documents that they have a “face-to-face encounter” with the patient, the service may be billed under the physician’s Medicare identification number. If there is no documentation of a direct interaction between the physician and the patient on the day of the encounter the service may only be billed at 85% of the Medicare physician fee schedule.