Physician assistants (PAs) are health professionals who are qualified to provide a broad range of medical and surgical services, including performing physical exams, diagnosing and treating medical conditions, assisting in surgery and prescribing medications. PAs practice under physician supervision, although the physician doesn't necessarily need to be on site. Supervision rules vary by state, and Medicare follows the state-established rules.

PA Qualifications

For Medicare to reimburse the services of physician assistants, the PA must have a state-issued PA license. The PA must either have graduated from a PA program accredited by the Accreditation Review Commission on Education for the Physician Assistant (ARC-PA) or one of the agencies that preceded ARC-PA: the Commission on Accreditation of Allied Health Education Programs or the Committee on Allied Health Education and Accreditation or have passed the national certification examination from the National Commission on Certification of Physician Assistants.

Criteria for Coverage

Medicare reimburses for PA services that would be considered physician’s services if performed by a Medical Doctor (MD) or Doctor of Osteopathy (DO). Medicare only covers services that the qualified PA can legally provide in the state where the PA works and also requires that services be performed under the general supervision of an MD or DO, although the physician supervisor does not have to be physically present unless the state requires otherwise. The services must be medically reasonable and necessary and not excluded from coverage by Medicare rules.

Incident Services

Auxiliary personnel may provide services and supplies in a physician's office that are “incident to” the professional services of a physician or a non-physician practitioner, such as a PA. Medicare may cover these services for a PA if a physician initially saw the patient and maintains an active part in patient care, the services are an integral part of the patient’s normal course of treatment, the services are commonly furnished in the physician’s office and are an expense to the physician and the physician is present in the office and available for direct supervision if needed.


If the PA is a W-2 employer or 1099 independent contractor for a medical practice, the practice must bill Medicare using the PA’s National Provider Identifier (NPI). Only if the physician in the practice first assesses the patient and establishes a treatment plan can the practice bill Medicare using a physician’s NPI. However, incident to services claims must be billed under the supervising physician’s NPI. If the PA works for a hospital or Skilled Nursing Facility, that facility must bill for the services.


Medicare pays for PA services only on assignment, meaning that the Medicare provider will accept the Medicare-allowed amount as full payment for services and cannot bill the patient except for copayments, deductibles or coinsurance. Medicare makes payments only to a PA's Medicare-enrolled employer or directly to a PA who works as an independent contractor. Medicare covers PA services at whichever amount is less: 80 percent of the actual charge or 85 percent of the Medicare physician fee schedule (PFS) amount except for surgical PA services for which Medicare pays 85 percent of 16 percent of the PFS amount.