More and more interventional radiologists are practicing clinically by establishing IR clinics where patients are seen, not only for interventional radiology procedures, but also for evaluation and management services. Most such practices are also making use of physician assistants (PAs) and nurse practitioners (NPs) to provide services more efficiently and productively.  IRs should understand the rules for how the service of the physician extenders can be delivered and reimbursed.

The professional services of PAs and NPs can be billed two ways under Medicare. First, for some non-hospital settings, the PA or NP’s services may be billed as "incident to" physician services, in which case the services are paid at 100 percent of the Medicare physician fee schedule, as if the physician performed the service. Second, the procedures may be billed as services of these non-physician practitioners (NPPs), under the PA or NP’s license, and are generally paid at 85 percent of the fee schedule amount, in both hospital and non-hospital settings.

"Incident to" Physician Services

Some services and supplies furnished incident to a physician’s professional services by non-physician personnel in private practice are paid by Medicare as if the physician actually performed the service (i.e., at 100 percent of the fee schedule). In general, to be covered “incident to” the services of a physician, services and supplies must be an integral, although incidental, part of the physician’s professional service, furnished under the physician’s “direct personal supervision” and furnished by the physician or by an individual who qualifies as an employee of the physician. There is no "incident to" billing permitted for hospital patients. Failure to understand that incident to billing may not be performed in a hospital setting appears to be one of the biggest source of improper billing by radiology groups that use physician extenders to perform interventional services in hospitals. 
 
It must be noted that coverage of services and supplies incident to the professional services of a physician in private practice is limited to situations in which an IR performed an initial service for the patient. Further, the physician must perform subsequent services at a frequency (e.g., one out of every three) that reflects his or her active participation and management of the course of treatment. Also, the incident to service must be under the direct personal supervision of the IR. This obligation is identical to the rules for supervising certain diagnostic tests, such as MR or CT exams with contrast; and therefore, the IR must be present in the office suite and immediately available to provide assistance and direction throughout the time the NPP is performing services. Colloquially, this is sometimes referred to as being "within shouting distance," although availability of the physician by telephone does not count.
 
To be paid as incident to, the NPP providing services must be considered an employee under the common law test. Generally, this test measures the control of means and methods of work. The employee may be a part-time, full-time or leased employee of the supervising physician, physician group practice or of the legal entity that employs the physician who provides direct personal supervision.

Directly as PA or NP Services

If payment as an “incident to service” is not available, it may be possible for the NPP to perform and bill for the services under his or her own statutory benefit. In general, to be covered by Medicare, the services must meet the following conditions:

• The services would be covered as a physician service if furnished by a physician
• The NPP is legally authorized to perform the services in the state where performed
• The services are performed under the general supervision of the physician (the physician need not be physically present unless required by state law, but must be immediately available for consultation)
• The furnished services are billed by the NPP’s employer. The NPP must reassign payment to the PA’s employer and complete form CMS-855R; the NPP must also enroll as an individual practitioner and have been assigned a Physician Identification Number (PIN) or National Provider Identifier (NPI)

Practical Application

Interventional radiologists considering whether to employ NPPs must consider the fit of these services to the physician’s practice, as well as the ability to bill for the NPP’s services. In the hospital setting, if the PA or NP has been appropriately credentialed, his or her services may be billed as PA or NP services, at 85 percent of the fee schedule rate, and the physician must provide the level of supervision required under state licensing laws. In the office setting, physicians can bill NPP’s services either as PA or NP services or, under certain circumstances, as "incident to" services that are paid as if the physician provided the service.
 
Medicare services can be billed "incident to" when the physician provides direct personal supervision, which is generally more than the general supervision required under state licensing laws. The physician need not perform a service every time the NPP does, but must perform an initial service for the patient. The IR must also perform subsequent services sufficient enough to demonstrate the physician’s active participation in and management of the patient’s care.