Question: Answer: Incident-to billing doesn't apply between two physicians. You cannot bill services provided by one physician under another physician's name or national provider identifier (NPI). Billing under the name of a physician who did not perform the service could lead to allegations of false claims submissions. Incident-to billing may apply when a mid-level provider or non-physician practitioner (NPP), such as a physician assistant (PA), nurse practitioner (NP), or clinical nurse specialist, provides a service under the direct supervision of a physician. If the service meets incident to criteria, you can bill the service under the physician's NPI rather than the NPP's. In this case, physician A should bill for the service.