Physician's authorization of NPP's services is a rule you can't miss. The Centers for Medicare and Medicaid Services (CMS) recognizes non-physician practitioners (NPPs) for payment purposes by reimbursing physicians for services provided "incident to" a physician's care. However, CMS has made it clear in 2008's Transmittal 87 that payers will not reimburse these services unless there is physician documentation authorizing the incident-to service. You could end up dazed and confused if you don't fully understand incident-to rules. But you can't afford not to -- Medicare reimburses at 100 percent of the physician fee schedule when services are billed in the physician's name as an incident-to service, and 85 percent when billed under the NPP's name if incident-to guidelines are not fulfilled. Fortunately, you have ways to increase your knowledge about incident-to services. Here are 3 important guidelines. 1. Meet CMS-Set Criteria CMS' Benefit Policy Manual defines "incident to" as "services furnished as an integral although incidental part of a physician's personal professional service." CMS pays NPP office service reported under a physician's NPI at 100 percent, provided you meet these requirements: A Must: 2. Document Supervision Since 2008, CMS has pushed for the physician to document his approval of an NPP to provide follow-up services. Example: The initial physician service in this case is reported as 99203 under the physician's NPI, which pays about $103 in reimbursement based on the Medicare fee schedule non geographically adjusted (3.03 RVUs multiplied by 2011 conversion factor of 33.9764). Additionally, follow-up services provided by the NPP which might be reported (e.g., 99213) under the physician's NPI, after being provided, as "incidentto" the physician's plan of care. The NPP should provide evidence of the required physician supervision. This can easily be accomplished through a simple notation in the record, such as "Service performed under thesupervision of Dr. Smith." A co-signature is not required for billing purposes, but may be required for licensure issues involving physician assistants or as required by the state. 3. Be Aware of NPP Limitations When a patient comes to the office when no physician is around, the NPP can see and treat her. The NPP can even provide a service within his or her state law guidelines for scope of practice as long as the state's supervision requirements are met. However, in this case, you should bill the services out to Medicare under the NPP's own NPI and not the physician's, NPI. Medicare will pay for the service at 85 percent of the fee schedule. Advice: It's essential that you know these information for each of your payers. You shouldn't assume that every payer follows Medicare's rules. This includes your state Medicaid program. Many state Medicaid programs have their own individual NPP billing and credentialing rules separate from Medicare and do not necessarily accept incident to billing. Option: