Medicare Incident-To Billing: The Rules As They Now Read

Medicare incident-to billing is defined at 42 CFR 410.26, with the supervision levels themselves defined at 42 CFR 410.32(b)(3). Both were read on 17 September 2026 against the current eCFR text, which was up to date as of 15 September 2026. Section 410.26 has been amended repeatedly since 2020 — most recently at 91 FR 12079 on 12 March 2026, and before that at 90 FR 50007 and 89 FR 98555 — so a guide built on a 2020 citation is describing a rule that has since changed twice.

The regulation's purpose is to let a practitioner use auxiliary personnel to extend the practice while the practitioner retains the supervisory relationship. The payment differential follows from that: services billed by a physician assistant under their own NPI are paid at 85 percent of the physician fee schedule amount under 42 CFR 414.52(d), and the same limit applies to nurse practitioners and clinical nurse specialists under 42 CFR 414.56.

Where the manual and the regulation diverge. Chapter 15, section 60.2 of the Medicare Benefit Policy Manual states that "the physician must be physically present in the same office suite and be immediately available to render assistance if that becomes necessary." That language predates the amendments that added virtual presence to the definition of direct supervision. Where the manual and the regulation conflict, the regulation is the binding text — but a compliance programme written to the stricter manual language will be defensible either way, so the practical question is whether you want the flexibility, not whether you are permitted it.

The regulation lists its conditions at 410.26(b). Read together with the definitions at 410.26(a), they are:

1. Noninstitutional setting, noninstitutional patients. The regulation defines noninstitutional setting as all settings other than a hospital or skilled nursing facility. That is broader than the "office only, POS 11" rule that most guides state — the test in the regulation is institutional versus not, not a specific place-of-service code. Hospital and SNF settings are out; your place-of-service coding still has to match where the service was actually furnished.
2. Integral though incidental to the practitioner's service in the course of diagnosis or treatment of an injury or illness.
3. Commonly furnished without charge or included in the practitioner's bill.
4. Of a type commonly furnished in the office or clinic of a physician or other practitioner.
5. Furnished under direct supervision, with two exceptions stated in the same paragraph: designated care management services may be furnished under general supervision, and behavioral health services provided by auxiliary personnel may be furnished under general supervision.
6. Furnished by the physician, a practitioner with an incident-to benefit, or auxiliary personnel — where auxiliary personnel is defined broadly enough to include employees, leased employees and independent contractors, provided they are not excluded from federal health care programs, have not had Medicare enrolment revoked, and meet any State licensure requirement for the service.
7. Furnished in accordance with applicable State law.
8. The practitioner may be an employee or an independent contractor.
9. A drug administered to refill an implanted DME item is payable only to the physician as a drug incident to a physician's service, not to a pharmacy or supplier as DME.

One sentence in 410.26(b)(5) does more work than the rest of the paragraph: the practitioner supervising the auxiliary personnel need not be the same practitioner treating the patient more broadly, but only the supervising practitioner may bill for the incident-to service. That resolves the common group-practice question directly — coverage does not fail because the supervising physician that day is a partner rather than the patient's own physician — and it sets the documentation requirement, because the claim must carry the practitioner who actually supervised.

Where the "established patient, established plan" rule comes from. It is not in 410.26. It comes from Chapter 15, section 60.2 of the Benefit Policy Manual, which states that "there must have been a direct, personal, professional service furnished by the physician to initiate the course of treatment of which the service being performed by the nonphysician practitioner is an incidental part, and there must be subsequent services by the physician of a frequency that reflects the physician's continuing active participation in and management of the course of treatment." That is the actual standard: an initiating service by the physician, plus continuing active participation. "New patient equals never incident-to" is a serviceable shorthand for it, and "any new problem disqualifies" is a conservative reading of it, but neither phrase appears in the source — so when you write your policy, write the source language and note your own interpretation separately.

The structural fact is simple and citable: services billed under a physician assistant's own NPI are paid at 85 percent of the physician fee schedule amount (42 CFR 414.52(d)), and the same 85 percent limit applies to nurse practitioners and clinical nurse specialists (42 CFR 414.56). A qualifying incident-to service billed under the supervising practitioner's NPI is paid at the full fee schedule amount. The differential is therefore 15 percentage points of the fee schedule amount for the codes involved.

We are deliberately not publishing a per-encounter dollar figure or an annualised total. Any such number depends on your own code mix, your locality's geographic adjustment, the current conversion factor, and how many of your encounters would actually qualify — and a figure built on national averages and a guessed encounter count is a sales argument dressed as arithmetic.

To compute the real number for your practice: take your last twelve months of encounters rendered by PAs, NPs and CNSs; filter to Medicare Part B; filter again to the subset that would satisfy the conditions above on a per-encounter basis; and multiply that subset's allowed amounts by 15/85 to get the uplift you are currently forgoing, or by 15/100 against full-rate claims to get what you would lose by moving to NPP billing. The second filter is the one that matters, and it is the one every published estimate skips.

Published incident-to guidance tends to lean on settlement anecdotes. We are not repeating figures for False Claims Act settlements, because we could not tie a specific dollar range to a specific, retrievable source, and an unsourced settlement number is not a compliance control. What follows instead is the set of facts the regulation requires you to be able to demonstrate for any individual encounter you bill this way.

For each encounter billed incident-to, you must be able to show:

If any row cannot be evidenced for a given encounter, that encounter is not eligible, and the answer is to bill it under the rendering practitioner's own NPI rather than to reconstruct evidence afterwards. That is the entire compliance posture, and it does not require a settlement figure to justify.

Documentation should let a reviewer complete the table above from the chart alone, for a single named encounter.

In the record, per encounter:

• The prior practitioner encounter establishing the problem and the plan, retrievable and dated.
• The current note identifying the established problem addressed and confirming the plan was followed rather than changed.
• The name of the supervising practitioner for that specific encounter — not "the supervising physician" as a role, but the individual.
• Contemporaneous evidence of the required supervision. Where direct supervision applied, that means presence in the office suite or, where the service qualifies, real-time audio-video presence. A daily attestation, a sign-in record, or a system-generated timestamp all work if they are created at the time and can be produced later.
• The place of service consistent with where the service was actually furnished.

On the claim: the supervising practitioner is the rendering provider. The regulation is explicit that only the supervising practitioner may bill.

One operational note on the virtual-presence option. If you intend to rely on it, your evidence has to establish three things the office-suite version does not: that the connection was real-time audio and video rather than audio-only, that the supervising practitioner was available throughout the service, and that the service carried no 010 or 090 global surgery indicator. Build those three fields into whatever attestation you use before you rely on the flexibility, not after.

The failure patterns follow directly from the conditions, and each has a control that runs before the claim goes out.

1. No initiating practitioner service on file. A patient new to the practice has no prior practitioner encounter establishing the plan, so the manual's initiating-service standard cannot be met. Control: the scheduling or charge-entry system flags encounters with no prior practitioner visit for that problem.

2. A new problem inside an established relationship. The initiating service covered a different condition. Control: the auxiliary personnel's note has to name the established problem it is addressing; a note that opens a new problem routes to NPP billing automatically.

3. Supervision not actually in place. The supervising practitioner was at the hospital, off-site, or otherwise unreachable during the encounter. Control: a contemporaneous presence record, not a retrospective attestation. Note that this failure is narrower than it used to be — real-time audio-video presence now satisfies direct supervision for services without a 010 or 090 global surgery indicator — but "unavailable" is still unavailable.

4. No identifiable supervising practitioner. The chart does not say who supervised. Control: the field is mandatory in the encounter template, and the claim is held if it is empty.

5. Institutional settings. Encounters in a hospital or skilled nursing facility fall outside the regulation's noninstitutional-setting condition. Control: a place-of-service rule at claim edit.

6. Applying direct supervision where general supervision would do, or the reverse. Designated care management services and behavioral health services furnished by auxiliary personnel may be furnished under general supervision. A practice that does not distinguish these either forgoes flexibility it has, or applies general supervision to a service that still requires direct. Control: maintain the eligible service list explicitly rather than applying one supervision rule to everything.

7. Auxiliary personnel qualification not checked. Exclusion status, Medicare enrolment revocation and State licensure are all conditions in the definition of auxiliary personnel. Control: exclusion screening on a schedule, and licensure verification at hire and at renewal.

Bill under the rendering practitioner's own NPI, at the 85 percent limit, whenever any condition in the check cannot be evidenced for that specific encounter:

• No prior practitioner encounter initiating the course of treatment for this problem.
• The encounter addresses a problem the practitioner has not evaluated.
• The plan of care is being changed rather than followed.
• The required supervision was not in place, in person or — where permitted — virtually.
• The supervising practitioner for the encounter cannot be identified.
• The setting was institutional.

The defensible default is to bill under the rendering practitioner's own NPI and switch to incident-to only for encounters affirmatively verified against the check, rather than the reverse. Mechanically, that means the practice management system defaults NPP claims to the NPP's NPI, and a verification step — not a habit — moves an encounter to the supervising practitioner's NPI.

The cost of that default is 15 percentage points of the fee schedule amount on the encounters that would have qualified. The cost of the opposite default is that every unqualified encounter billed at the full rate is an overpayment you will eventually repay, with the difference that you will repay it on someone else's timetable rather than your own.