Know the rules before you try to bill incident-to. Answer: To qualify for incident-to, the NPP must have seen the Medicare patient during a prior visit and established a clear plan of care. If the NPP is treating a new problem for the patient, or if the doctor has not established a care plan for the patient, then you cannot report the visit incident-to. Important: When meeting the requirements for established plan of care follow up, if the internist does not directly supervise the NPP, the incident-to rules do not apply. Direct supervision means a supervising physician must be immediately available in the office suite. The supervising physician, however, does not necessarily need to be the same physician that established thepatient's care plan. Example: An established Medicare patient reports to the physician on March 13. The doctor performs an E/M service, diagnoses the patient with pneumonia, writes prescriptions and, as part of plan of care, asks the patient to return in one week to follow up with the nurse practitioner. On March 21, the patient returns to the doctor for a follow-up visit. The NPP evaluates the patient's signs and symptoms and performs an examination. The nurse practitioner recommends finishing the course of antibiotics and returning for follow up in three weeks. In this example, you can report the NPP's service incident to the physician. On the claim, report the appropriate level E/M code. Don't forget to file the claim under the supervising physician's national provider identifier (NPI) rather than the NPP's NPI; this ensures you 100 percent pay for the E/M, while coding under the NPP's NPI results in 85 percent pay for the service. Don't overlook that the NPP has the proper credentials to perform incident-to services. The NPP must be, "licensed by the state under various programs to assist or act in the place of the physician," according to the Medicare Benefit Policy Manual, chapter 15. Best bet: Check your state and local Medicare regulations for NPP qualifications. If the NPP does not meet one or both sets of guidelines, don't bill incident-to for her services. (Editor's note: The Medicare Benefit Policy Manual, Chapter 15, is available for download at: www.cms.hhs.gov/Manuals/downloads/bp102c15.pdf.)