Incident-to Billing: Navigating Medicare and Commercial Payer Guidelines

Incident-to billing lets a practice collect 100% of the Medicare fee schedule for qualifying visits performed by a nurse practitioner or physician assistant, instead of 85% . It also comes with strict conditions, and a visit billed incident-to that didn't qualify is a denial at best and an audit finding at worst. 

This guide will cover the fundamentals of incident-to billing, as well as the variations in billing rules between Medicare and commercial insurers, and give guidance that will help get the greatest reimbursement possible while adhering to regulations. 

What Is Incident-to Billing?

Incident-to billing is a Medicare Part B provision that allows services performed by a non-physician practitioner (NPP) to be billed under a supervising physician's National Provider Identifier (NPI), as if the physician personally rendered the service. 

Under Medicare Benefit Policy Manual, Chapter 15, Section 60, NPP services billed on their own NPI are reimbursed at 85% of the Medicare Physician Fee Schedule. When those same services meet all incident-to requirements, the claim is reimbursed at the full 100% rate.

Some incidental services may also be provided by auxiliary clinical staff like medical assistants, but these services must still be billed on the supervising physician's/NPP's NPI and not the auxiliary staff member's NPI. 

Essential Conditions for Incident-to Billing

Before a service can be billed as incident-to, it must meet a few fundamental requirements. Think of these as a quick eligibility checklist; if even one condition is missing, the service cannot be billed under the physician's NPI.

• The patient must be established, and the physician must have personally created the diagnosis and treatment plan.
• The visit must focus on an existing condition. If the patient comes in with a new complaint or diagnosis, the physician must evaluate the patient and establish a new plan of care.
• Direct supervision is required. The supervising physician, or another qualified physician within the same group practice, must be immediately available while the service is being provided.
• The service must support the physician's ongoing treatment plan, meaning it should be an integral, though incidental, part of the physician's professional service rather than a separate episode of care.

The golden rule: If it's a new patient first visit or a new medical issue, then it's not incident to billing. Practices can follow this rule and prevent many compliance issues and audit findings from incident-to billing.

Incident-to Billing vs. Split/Shared Billing

Each of these billing options is often mistaken for the other, but they are only used in isolation and are determined by the place of service. 

Factor	Incident-to Billing	Split/Shared Billing
Setting	Private office (POS 11)	Facility settings (POS 19, 21, 22, 23)
Patient status	Established patients, established problems only	New and established patients
Billing determined by	Direct physician supervision during the visit	Whoever performed the substantive portion (over half the total time, or the substantive part of MDM)
Reimbursement	100% of PFS under the physician's NPI	Rate tied to whichever provider bills

CMS Requirements for Incident-to Billing

CMS has established documentation, supervision and eligibility requirements for billing a service as incident-to. The following criteria are the basis of a compliant incident-to billing under Medicare. 

Initial Physician Evaluation and Treatment Plan

• The supervising physician personally performed the initial service for the specific condition being treated and established the diagnosis and treatment plan.

Established Patients and Existing Conditions

• Only established patients qualify, the visit must address an existing problem, with no new complaints or diagnoses.

Supervision Requirements

• For procedural services carrying a 10- or 90-day global period (biopsies, destructions, complex injections, fracture care), the supervising physician must be physically present in the office suite.
• For routine follow-up visits without a global period, the physician may supervise in-office or virtually through a real-time audio-video connection, audio-only does not qualify.

Ongoing Physician Involvement

• The supervising physician remains actively involved in the course of treatment, not merely co-signing notes.

Eligible Care Settings

• The service takes place in a non-institutional setting, CMS defines this as any setting other than a hospital or skilled nursing facility.

Employment and Credentialing Requirements

• Both the NPP and the supervising physician are credentialed with Medicare, and the NPP is an employee (or contracted staff) of the supervising practice.

When Incident-to Billing Does Not Apply

Incident-to billing does not apply when:

• The patient is new.
• An established patient presents a new medical complaint.
• The supervising physician is neither physically present nor virtually available in real time by audio-video connection.

Documentation and MAC-Specific Requirements

CMS's basic rules can be supplemented by documentation requirements imposed by Medicare Administrative Contractors (MACs). Practices working in more than one state should verify the MAC guidance that is relevant to each state. 

Scenarios: When Incident-to Applies

Scenario 1: Qualifies for Incident-to

A patient has been a regular patient at Medicare. A patient has been a regular patient at Medicare and is being treated for hypertension. Previous diagnosis by her doctor and documentation of treatment plan. She comes back and is seen by the practice nurse practitioner who checks her home blood pressure, it is still high, and the clinic doctor had already explained a plan of care, which the nurse practitioner follows in making the adjustment. There is a supervising physician in the office suite during the visit.

This visit qualifies as incident-to, since it addresses an established problem under a plan the physician already created, and supervision requirements are met.

Scenario 2: Fails - New Problem, Established Patient

The same patient returns for a follow-up but now also mentions new knee pain unrelated to her hypertension. The nurse practitioner evaluates and manages the hypertension, which still qualifies as incident-to, but cannot bill the knee pain portion the same way, because the physician never personally evaluated this new complaint or established a diagnosis and plan for it. The knee-pain component must be billed under the NP's own NPI at 85%.

Scenario 3: Fails - New Patient

A physician assistant sees a Medicare patient who is brand new to the practice. Even if the supervising physician is physically present and briefly greets the patient, this cannot be billed incident-to, since there is no pre-existing treatment plan for a new patient. The visit is billed under the PA's own NPI.

Scenario 4: Fails - Supervision Gap

Established patient is seen by an NP for a routine follow-up, while the supervising physician is on hospital rounds, and it is not possible to conduct real time video. Note that, due to failure to provide direct supervision (physical or live AV) it is not possible to bill this visit incident-to and it will be under the NP's own NPI. 

Scenario 5: 2026 Virtual Supervision in Action

An established patient visits the NP for a regular, no change follow-up visit. The supervising physician is not present in the building but can be "seen" and "heard" by the building in real time via live two-way video. This meets the 2026 rule for incident-to. But if the same visit involves a joint injection with a 10-day global period, virtual supervision is no longer sufficient and the physician must be physically present in the office suite for this procedure to count. 

How Commercial Payer and Medicaid Rules Differ

Incident-to is a CMS policy and most Medicare Advantage plans do adhere to it. It is not required to be replicated by commercial payers or state Medicaid programs, and Medicaid programs can have significantly different rules: 

• Some commercial payers prohibit incident-to billing entirely and require the actual rendering provider to be the billing provider.
• Others permit incident-to but require an SA modifier appended to the E/M code to flag the service as NPP-rendered, sometimes while still reimbursing at 85% rather than 100%.
• Credentialing requirements for NPPs may differ from Medicare's, and some payers require NPPs to be independently credentialed regardless of supervision.
• State Medicaid programs each set their own incident-to policies, which may not align with CMS or with each other across state lines.
• When using incident-to billing on a non-Medicare claim, it's important to check the language in the provider manual or contract for the specific payer before assuming it applies to Medicare.

Documentation Checklist and Common Compliance Mistakes

Medical records supporting an incident-to claim should clearly show:

• The identity of the individual who rendered the service.
• The supervising physician's presence (physical or, where permitted, real-time virtual) at the time of service.
• The physician's initiation of treatment and continued, active involvement in the plan of care.
• That the service falls within the NPP's scope of practice under applicable state law.
• A clear link between the auxiliary/NPP service and the supervising physician's own professional service.

The most frequent errors practices make:

• Billing a new patient's visit as incident-to.
• Billing a new problem for an established patient as incident-to without a physician evaluation first.
• Treating phone availability as equivalent to direct supervision.
• Failing to reassess and re-document the plan of care after a significant clinical change.
• Not tracking which physician was on-site (or connected virtually) for each date of service.

The OIG's national audit of Medicare Part B incident-to payments, with expected completion in FY 2026, makes this an active compliance risk rather than a hypothetical one. Improperly billed incident-to claims can trigger repayment demands, civil monetary penalties, and False Claims Act exposure.

What This Means for Your Practice

• Check your supervision log. For each date of service, can you show which physician supervised and whether they were in the office suite or on live video?
• Flag procedures with a 010 or 090 global period. Those still need the physician physically in the office suite, even under the 2026 virtual-supervision rule.
• Pull a sample of NPP visits billed under a physician's NPI and look for new problems. One new complaint means the whole visit bills under the NPP at 85%.
• Read each non-Medicare payer's manual before billing incident-to to them. Some prohibit it, some require modifier SA, some pay 85% regardless.
• With an OIG audit of Part B incident-to payments active, run the documentation checklist as a monthly internal review rather than a one-off.

Make Incident-to Billing Simpler, Safer, and More Profitable with BillingFreedom 

Incident-to is real revenue only when every claim meets the supervision, documentation and payer rules. BillingFreedom aids practices in applying CMS's incident-to rules properly, keeping a record of physician supervision by date of service, and adjusting documentation processes for each payer according to the payer's documentation requirements, including those that follow CMS's lead. 

Our medical billing and coding team remains current with changes to CMS rules and guidance for MACs in physician fee schedule rates, such as the virtual supervision change, to ensure practices receive the rate they are entitled to and aren't caught with their hands tied when they've earned it or facing denials and audit exposure when they have not. 

For more details about our exceptional medical billing services, please don't hesitate to contact us via email at info@billingfreedom.com or call us at +1 (855) 415-3472. 

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