Incident-To Billing: Rules for Billing NPP Services Under a Physician
Incident-to billing is a Medicare rule that lets services by non-physician practitioners (NPs, PAs) be billed under the supervising physician's NPI at 100% of the fee schedule, instead of the NPP's reduced rate, when strict conditions are met — an established patient, an established plan of care, and direct physician supervision in the office suite.
- Enforced by
- CMS / DOJ
- Applies to
- Medicare NPP services in office setting
- Penalty
- Recoupment (15% overpayment) + FCA risk
What is incident-to billing?
Incident-to is a Medicare rule that lets a non-physician practitioner's office services be billed under the physician's NPI and paid at the full 100% fee schedule, instead of the 85% Medicare normally pays for NPP services directly. That 15-point difference is the entire reason the rule exists — and the entire reason it gets abused.
It applies to Original Medicare in the office setting. It does not apply to new patients or new problems, and commercial payers may follow different rules.
What are the core requirements?
- Established patient — never a new patient; the physician must have seen them and set the course of care.
- Established plan of care — the NPP follows a plan the physician created; a new or worsening problem breaks incident-to.
- Direct supervision — a physician is present in the office suite and immediately available during the service.
- Physician involvement — ongoing physician participation in the patient's care, documented.
How does this play out in practice?
Example: an established diabetic patient sees the NP for a routine follow-up on the physician's existing plan, with Dr. A in the suite. Bill under Dr. A at 100% — valid incident-to. Same patient, same NP, but the patient now reports new chest pain, so the NP evaluates a new problem: that visit is not incident-to and must be billed under the NP at 85%. Same patient again, but Dr. A is at the hospital that afternoon and Dr. B is covering — bill under Dr. B (who supervised), not Dr. A.
Where does incident-to go wrong?
The failure modes are predictable: billing new patients as incident-to, billing new problems as incident-to, and billing when no physician was on site. Each is a 15% overpayment that scales fast across a busy practice and triggers the 60-day overpayment rule once identified. Because the pattern is systematic, it draws False Claims Act scrutiny and appears on the OIG Work Plan. Solid documentation of patient status, the plan of care, and the supervising physician present is the defense.
Frequently asked questions
It is a Medicare billing method that allows a non-physician practitioner's services in the office to be billed under the supervising physician's NPI, paid at 100% of the Medicare Physician Fee Schedule rather than the 85% NPPs are normally paid. In exchange, Medicare imposes strict conditions on supervision, patient status, and the plan of care.
The patient must be established (not new), with an established plan of care the physician created; the NPP must be following that plan without changing it for a new problem; a physician must provide direct supervision — physically present in the office suite and immediately available (not necessarily in the room); and the service must be one the physician initiated and remains actively involved in. Miss any element and it is not incident-to.
Because the requirements are easy to violate in a busy office and the payment difference (100% vs 85%) creates an incentive to bill incident-to when it does not qualify. A new patient, a new problem for an established patient, or the supervising physician being off-site all break the rule. Billing incident-to anyway is a 15% overpayment per visit and a recurring audit and False Claims Act target.
Sources & further reading
Reviewed by the ImmediCare Solutions RCM team
Certified billers and coders handling claims across 50+ specialties nationwide. This entry is reviewed against current payer policy and CMS rules. Last review: Jul 5, 2026.
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