Incident-To Billing: The Conditional Test, Setting by Setting

Incident-to billing is not a code, a modifier or a place-of-service value. It is a conditional test: a set of coverage conditions that, when all of them are satisfied, allow a service actually performed by auxiliary personnel to be billed under a physician’s or eligible practitioner’s National Provider Identifier rather than the rendering person’s own. Because it is a test rather than a lookup, the honest answer to “can we bill this incident-to?” is almost always conditional — on the setting, on what the physician did first, on who is physically or virtually present, and on what benefit category the service falls into.

Three sources govern it, and they do not say identical things. The statutory hook is section 1861(s)(2)(A) of the Social Security Act. The regulation is 42 CFR 410.26, whose text as codified on 1 August 2026 reflects amendments through 91 FR 12079 (12 March 2026). The operational guidance is the Medicare Benefit Policy Manual, Pub. 100-02, Chapter 15, §60, whose §60 heading carries Rev. 12425 (issued 21 December 2023, effective 1 January 2024) while most of its subsections — §§60.1 through 60.4 — still carry Rev. 1 of 1 October 2003. Where the regulation and the manual diverge, that gap is usually the manual lagging, and it is where most of the avoidable errors live. All figures and supervision levels below are drawn from those primary texts; none are estimates.

The Conditions in the Regulation

42 CFR 410.26(b) sets out what Medicare Part B requires before it will pay for services and supplies incident to the service of a physician or other practitioner. The conditions, in the regulation’s own structure:

• The services and supplies must be furnished in a noninstitutional setting to noninstitutional patients. The regulation defines noninstitutional setting as all settings other than a hospital or skilled nursing facility.
• They must be an integral, though incidental, part of the service of the physician or practitioner in the course of diagnosis or treatment of an injury or illness.
• They must be commonly furnished without charge or included in the bill of the physician or practitioner.
• They must be of a type commonly furnished in the office or clinic of a physician or practitioner.
• In general they must be furnished under the direct supervision of the physician or practitioner — with two named exceptions discussed below.
• They must be furnished by the physician, a practitioner with an incident-to benefit, or auxiliary personnel.
• They must be furnished in accordance with applicable State law.
• The physician or practitioner may be an employee or an independent contractor.

Auxiliary personnel is defined generously and precisely: any individual acting under the supervision of the physician or practitioner, regardless of whether that individual is an employee, leased employee or independent contractor of the practitioner or of the same entity that employs or contracts with the practitioner — who has not been excluded from Medicare, Medicaid and other federally funded programs by the Office of Inspector General, has not had Medicare enrollment revoked, and meets any applicable State requirements including licensure. Employment status, in other words, is not the gate. Exclusion status and State licensure are.

Direct Supervision: What It Requires, Including Virtually

The regulation does not define direct supervision inside §410.26; it points to the definition at 42 CFR 410.32(b)(3)(ii), which reads: direct supervision in the office setting means that the physician (or other supervising practitioner) must be present in the office suite and immediately available to furnish assistance and direction throughout the performance of the service. It does not mean the practitioner must be in the room. The two adjacent levels, from the same regulation, are worth holding alongside it because the wrong one is often assumed:

• General supervision — the service is furnished under the practitioner’s overall direction and control, but the practitioner’s presence is not required during the performance of the service.
• Direct supervision — present in the office suite and immediately available throughout.
• Personal supervision — the physician must be in attendance in the room during the performance of the procedure.

The regulation now carries a virtual-presence provision in both §410.26(a)(2) and §410.32(b)(3)(ii), in identical words: the presence of the physician (or other practitioner) required for direct supervision may include virtual presence through audio/video real-time communications technology (excluding audio-only) for services without a 010 or 090 global surgery indicator. Three things follow from that sentence and are easy to get wrong. Audio-only does not satisfy it. It does not extend to services carrying a 010-day or 090-day global surgery indicator. And it is a supervision provision, not a telehealth provision — it changes where the supervisor may be, not how the service is furnished to the patient. Virtual direct supervision has been the subject of repeated short-term extension since it first appeared, so confirm its status for the current calendar year against the current fee-schedule rule and your MAC rather than treating the codified sentence as settled indefinitely.

What the Physician Must Have Done First

This is the requirement most often summarised as “established patient, established plan of care” — a phrase that appears nowhere in the manual. What Pub. 100-02 Ch. 15 §60.1B and §60.2 actually say is more specific and more useful:

Such a service or supply could be considered to be incident to when furnished during a course of treatment where the physician performs an initial service and subsequent services of a frequency which reflect his/her active participation in and management of the course of treatment. (However, the direct supervision requirement must still be met with respect to every nonphysician service.)

And, for non-physician practitioners billing incident-to a physician, §60.2 states it more strongly still: 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.

Two operational readings follow. A genuinely new problem presented at a visit is outside the course of treatment the physician initiated, so the incident-to path does not reach it — not because a rule names “new problems”, but because there is no physician-initiated course of treatment for that problem to be incidental to. And the manual explicitly does not require the physician to perform a service on the same occasion; what it requires is an initiating service plus a continuing pattern of physician involvement. The manual sets no numeric visit interval for what “a frequency which reflect[s] active participation” means, and neither does the regulation. Any specific interval a payer, consultant or template asserts is that payer’s or author’s interpretation, not a federal threshold — treat it as such and get it in writing from the payer that asserts it.

Who May Render, and Who May Bill

The manual and the regulation separate these two questions cleanly, and conflating them is a common source of overpayment findings.

Who may render. Auxiliary personnel, as defined above. That includes nurses, technicians and therapists, and also non-physician practitioners — the manual names certified nurse midwives, clinical psychologists, clinical social workers, physician assistants, nurse practitioners and clinical nurse specialists as examples — performing not only routine office-staff tasks but also services ordinarily performed by a physician, such as minor surgery, setting casts or simple fractures, and reading x-rays.

Who may bill. For purposes of §60, the manual defines “physician” to mean physician or other practitioner — physician, physician assistant, nurse practitioner, clinical nurse specialist, nurse midwife, and clinical psychologist — authorised by the Act to receive payment for services incident to his or her own services. The regulation adds a rule the 2003-vintage manual text does not contain: the physician or practitioner supervising the auxiliary personnel need not be the same one treating the patient more broadly, but only the supervising practitioner may bill Medicare for incident-to services. Reassignment sits underneath all of this: the manual requires that the practitioner personally furnishing or supervising the service have a relationship with the legal entity billing and receiving payment that satisfies the requirements for valid reassignment, and that the service represent an expense incurred by that entity.

The most consequential distinction here is that many of these practitioners have their own benefit categories. The manual is explicit: physician assistants, nurse practitioners, clinical nurse specialists, certified nurse midwives, clinical psychologists, clinical social workers, physical therapists and occupational therapists may all provide services without direct physician supervision and bill directly. Incident-to is therefore a choice with consequences, not a requirement — and the incident-to conditions only apply when that path is chosen. The manual instructs MACs directly: A/B MACs (A) and (B) must not apply incident to requirements to services having their own benefit category. Diagnostic tests, covered under §1861(s)(3), have their own supervision requirements that may be more or less stringent, and need not also meet the incident-to requirement. Pneumococcal, influenza and hepatitis B vaccines, covered under §1861(s)(10), likewise need not.

How the Answer Changes by Setting

Office and clinic (the base case)

The full §410.26 test applies: noninstitutional setting, direct supervision in the office suite, physician-initiated course of treatment. In a physician-directed clinic, §60.3 relaxes one element only. Such a clinic is defined by three conditions: a physician is present to perform medical (not administrative) services at all times the clinic is open; each patient is under the care of a clinic physician; and the nonphysician services are under medical supervision. Where those hold, direct supervision may be the responsibility of several physicians rather than an individual attending, and the physician ordering a particular service need not be the physician supervising it — so services performed in another department of the clinic can still qualify. What does not change: when auxiliary personnel perform services outside the clinic premises, they are covered only under the direct supervision of a clinic physician, and a referral to personnel not supervised by clinic physicians is not incident-to at all.

Hospital and skilled nursing facility

The incident-to benefit under §1861(s)(2)(A) does not reach them. The manual is unambiguous: for hospital patients and for SNF patients who are in a Medicare covered stay, there is no Medicare Part B coverage of the services of physician-employed auxiliary personnel as services incident to physicians’ services under §1861(s)(2)(A) of the Act. Such services are covered only under the hospital or SNF benefit, paid to the facility by the A/B MAC (A). Hospital outpatient incident-to services exist as a separate benefit with its own regulation, 42 CFR 410.27, and its own supervision rules — do not carry §410.26 reasoning across that boundary.

The patient’s home and other institutions

Direct supervision follows the auxiliary person, not the office. §60.1B gives the worked example: if a nurse accompanies the physician on house calls and administers an injection, the nurse’s service is covered; if the same nurse makes the calls alone, it is not covered even when billed by the physician, because the physician is not providing direct supervision. In a nursing or convalescent home, the manual states plainly that the availability of the physician by telephone and the presence of the physician somewhere in the institution does not constitute direct supervision.

One narrow, genuinely different rule applies to homebound patients. §60.4, tracing back to the Senate Finance Committee report accompanying the 1972 Amendments, waives the direct supervision criterion for individual or intermittent services to a homebound patient where all of the listed conditions are met: the patient is homebound; the service is an integral part of the physician’s service to a patient the physician is treating and is performed under general physician supervision by employees of the physician or clinic, with the physician ordering the services and retaining professional responsibility; the services are included in the physician’s or clinic’s bill and represent an expense incurred; they are reasonable and necessary; and, with a narrow exception, the service is not one that a home health agency in the local area could furnish. The services this covers are enumerated rather than open-ended — injections, venipuncture, EKGs, therapeutic exercises, catheter insertion and sterile irrigation, catheter changes and catheterised specimen collection, dressing changes, nasogastric tube replacement or insertion, removal of fecal impaction including enemas, and sputum collection, among others in the list at §60.4B. Work from the current list rather than from the principle.

Physical therapy, occupational therapy and speech-language pathology

Therapy is the setting split that catches the most people, because two benefit categories overlap. Pub. 100-02 Ch. 15 §230.5 sets the rules, and the governing principle is stated in one sentence: where the policies have different requirements, the more stringent requirement shall be met. The specifics:

• There is no coverage for services provided incident to the services of a therapist. PTAs and OTAs work under therapist supervision and their services may be billed by the therapist, but they are covered under the therapy benefit, not the incident-to benefit.
• PTA and OTA services may not be billed incident to a physician’s or NPP’s service. Where a PT and PTA (or OT and OTA) are both employed in a physician’s office, the assistant’s services — directly supervised by the therapist — may be billed by the physician group as PT or OT services under the enrolled therapist’s NPI. If the therapist is not enrolled, Medicare will not pay for the assistant’s services at all.
• Where therapy is billed incident-to, the personnel performing it need not hold a therapy licence unless State law requires one, but must meet every other therapist qualification — at minimum being a graduate of a training programme in that therapy. The manual names the professions this excludes: athletic trainers, massage therapists, recreation therapists, kinesiotherapists and low vision specialists may not have their services billed as therapy services.
• The direct supervision requirement applies even though a licensed therapist could perform the same service unsupervised in another setting.

Behavioral health and care management

Two supervision carve-outs sit in the regulation and not in the 2003-vintage manual text, which is precisely why they get missed. 42 CFR 410.26(b)(5) provides that designated care management services may be furnished under general supervision when provided incident to the services of a physician or practitioner, and that behavioral health services may be furnished under general supervision when provided by auxiliary personnel incident to those services. General supervision, as defined above, does not require the practitioner’s presence during the service. Which specific services fall inside “designated care management” and “behavioral health” for this purpose is set through fee-schedule rulemaking rather than in the regulation text, so check the current-year Physician Fee Schedule final rule and your MAC’s article before applying the general-supervision level to a given code.

Where the Regulation and the Manual Diverge

A CMS manual is not a substitute for the Code of Federal Regulations even when the manual is newer, and incident-to is a clean illustration. The regulation carries at least three provisions the manual’s §60.1–60.4 text does not reflect, because those subsections have not been substantively revised since 2003:

• Virtual presence satisfying direct supervision, subject to the audio-only and 010/090 global-indicator limits.
• General supervision for designated care management and for behavioral health furnished by auxiliary personnel.
• The supervising practitioner not needing to be the treating practitioner, coupled with the rule that only the supervising practitioner may bill.

Read both, reconcile them, and where they genuinely conflict rather than merely differ in coverage, the regulation controls. The same discipline applies to any list of “incident-to rules” circulating as a checklist or template: check each line against §410.26 and §60 before relying on it.

MAC Interpretation Varies — Say So in Your Policy

Incident-to is administered by Medicare Administrative Contractors, and the federal text leaves real interpretive room in at least three places: what frequency of physician involvement demonstrates “continuing active participation and management of the course of treatment”; what counts as the same office suite for immediate availability, particularly in multi-floor or multi-tenant buildings; and what documentation is expected to evidence the supervising practitioner’s presence. MACs publish their own articles and local guidance on these points and they are not uniform across jurisdictions. Two consequences worth building into an internal policy: cite your own MAC’s current article alongside §410.26 and §60, not instead of them; and where an internal rule is stricter than the federal text because a MAC said so, record which MAC and when, so the rule can be re-checked rather than becoming permanent folklore. Where an intended arrangement is genuinely ambiguous, a written MAC inquiry is a cheaper answer than an extrapolated one.

Getting this wrong has a defined downstream consequence rather than a vague one: a service billed under the physician’s NPI that did not meet the incident-to conditions was billed at the wrong payment rate by the wrong provider, and identifying that pattern is exactly what post-payment review is for — see the guides on clinical trial billing compliance and the False Claims Act for how a systematic billing error is characterised once it is found.

Frequently Asked Questions

Does the supervising physician have to be in the room?

No. Direct supervision at 42 CFR 410.32(b)(3)(ii) requires presence in the office suite and immediate availability to furnish assistance and direction throughout the performance of the service. Presence in the room is personal supervision, a different and more demanding level that applies to certain diagnostic tests, not to incident-to generally.

Can a nurse practitioner’s service be billed incident-to a physician?

It can, if every incident-to condition is met — including the physician having initiated the course of treatment and remaining actively involved, and the physician being present in the office suite. But an NP has an independent benefit category and can bill directly without physician supervision. Incident-to is an alternative billing path with additional conditions attached, not a requirement.

Can incident-to be billed in a hospital or skilled nursing facility?

Not under this benefit. 42 CFR 410.26(b)(1) restricts it to noninstitutional settings, defined as all settings other than a hospital or SNF, and the manual states there is no Part B coverage of physician-employed auxiliary personnel as incident-to services for hospital patients or SNF patients in a covered stay. Hospital outpatient incident-to services are a separate benefit governed by 42 CFR 410.27.

Is there a required number of physician visits to keep incident-to available?

Neither 42 CFR 410.26 nor Pub. 100-02 Ch. 15 §60 states a numeric interval. The federal standard is qualitative: an initiating physician service plus subsequent services at a frequency reflecting continuing active participation in and management of the course of treatment. Any specific number quoted to you is an interpretation — find out whose, and get it in writing.

Can direct supervision be provided over video?

The regulation permits virtual presence through real-time audio/video communications technology, explicitly excluding audio-only, for services without a 010 or 090 global surgery indicator. This provision has been extended by short-term action more than once, so verify it is in effect for the current year before relying on it.

Does incident-to apply to physical therapy in a physician’s office?

Sometimes, and under stricter rules. Therapy has its own benefit category, and Pub. 100-02 Ch. 15 §230.5 requires that where the therapy and incident-to policies differ, the more stringent applies. PTA and OTA services can never be billed incident-to a physician; there is no such thing as a service incident-to a therapist; and personnel furnishing therapy incident-to must meet all therapist qualifications except, where State law does not require it, licensure.

This guide summarises 42 CFR 410.26 and 410.32(b)(3) as codified on 1 August 2026, and Medicare Benefit Policy Manual Pub. 100-02, Chapter 15, §§60–60.4 and 230.5 as published by CMS. It is general reference material, not billing advice for a specific claim, and it does not reflect any individual MAC’s local guidance. Verify every condition against the current regulation, the current manual chapter and your own MAC’s published articles before applying it.

Related: see the Clinical Research Administration hub, Medicare coverage analysis for clinical trials for how coverage determinations are made before a claim is built, clinical trial claim coding, and modifier 25 for the adjacent question of when a separately identifiable E/M service can be reported at all.