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October 24, 2012 - Revised: 08.09.17

The "Incident to" Provision of Medicare

The term "incident to" refers to the services or supplies that are a key part of the physician's personal professional services in the course of diagnosis or treatment of an illness or injury. In plain language: under the "incident to" provision of Medicare, services are submitted under the physician's NPI but are actually performed by someone else. There are restrictions on the types of services that ancillary personnel may perform under this provision.

How does "incident to" work?

  • "incident to" is not applicable to some services. It applies only to services that do not have their own "benefit category" under Medicare. Benefit categories are defined by the Social Security Act (section 1861(s)). Under Medicare Part B, the following services have their own benefit categories and specific required levels of supervision:
    • Diagnostic tests, including x-rays and clinical laboratory tests
    • X-ray, radium, and radiation therapy, including isotopes
    • Surgical dressings, splints, casts, and other materials used to treat fractures and dislocations
    • Durable Medical Equipment (DME), prosthetics, and orthotics
    • Ambulance services
    • Pneumococcal vaccines
    • Services provided by Certified Registered Nurse Anesthetists (CRNAs)
    • Screening mammography and screening Pap smears
    • Bone mass measurement
  • Under Medicare Part B, "incident to" provisions apply in an office setting only. There is no incident to billing in a facility under Part B.
  • Direct physician supervision is required. This means the physician must be physically present in the office suite and immediately available while the service is being provided. (The physician is not required to be in the same room while the service is being provided.) For example, the physician cannot be: across the street, three blocks away, or available via cell phone (but not in person). The issue of "immediate availability" is one of patient safety; for example, if the patient has an adverse reaction to an injection, or passes out during a routine venipuncture, the physician must be immediately available to provide care to the patient.
  • The services must be the kinds of services that are commonly provided in a physician's office. This includes some minor surgeries, many diagnostic tests, some injections and infusions, and other types of care that are routinely provided in an office setting. If the service is not normally done in your office, do not submit it under "incident to" provisions.
  • The services must be part of the physician's services to diagnose or treat the injury or illness. It would not be appropriate to render services "incident to" for a new patient visit, a new course of treatment, for a new problem, or in the case of a significant change in an established condition.

Who may provide services "incident to" a physician?

  • Auxiliary personnel, such as registered nurses, technicians, or other qualified personnel, may perform a limited scope of office procedures, such as certain injections. Auxiliary personnel must be employed by the physician or the legal entity that employs or contracts with the physician.
  • Nonphysician practitioners (NPPs), including nurse practitioners and physician assistants. Although NPPs may provide services under their own NPIs and in accordance with state laws regarding scope of practice, NPPs may also provide services "incident to" a physician and submit these services under the physician's NPI, when all requirements for "incident to" are met. In these cases, payment is made at the physician rate, as if the physician personally performed the service.


  • There are no modifiers that signify a service was provided "incident to" a physician.
  • No documentation is required with initial claims for "incident to" services; however, the medical record should demonstrate that direct physician supervision was provided.
  • In all cases, the medical necessity of the services must be supported by the beneficiary's medical records.

Signature Requirements

In an "incident to" scenario signatures may be appended in one of the following ways:

  • The documentation should be signed by the supervising provider with a reference in the notes as to who performed the service
  • Co-signed
  • Signed by the NPP performing the service


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