Incident-to Billing: Compliance Requirements Most Practices Get Wrong

Incident-to billing is one of the most financially significant — and most frequently misunderstood — billing rules in outpatient Medicare. When a non-physician practitioner (NPP) such as a nurse practitioner or physician assistant provides services that qualify as “incident to” a physician’s professional services, the practice can bill Medicare under the physician’s National Provider Identifier at 100 percent of the physician fee schedule rather than the 85 percent rate that applies when the NPP bills independently. That 15 percent difference across hundreds of patient encounters per year adds up to substantial revenue — and substantial liability when the requirements are not met.

What “Incident To” Actually Means Under CMS Rules

The incident-to provision is codified in 42 CFR § 410.26 and further explained in the Medicare Benefit Policy Manual (Chapter 15, § 60). For a service to qualify as incident to a physician’s professional services, all of the following conditions must be met simultaneously:

• The physician must have initiated the plan of care. The patient must have been seen and evaluated by the billing physician, who established the diagnosis and the treatment plan. An NPP cannot initiate a plan of care and then bill that encounter as incident to.
• The physician must provide direct supervision. The billing physician must be physically present in the office suite (not necessarily in the same room) during the NPP’s service. Present in the building means present in the office suite — not in a different wing, a different floor, or a different location in the same building complex. Telephone or virtual availability does not satisfy direct supervision.
• The service must be an integral part of the physician’s ongoing course of treatment. The NPP is carrying out a treatment plan the physician established and is continuing to manage. If the patient’s condition has changed enough to require a new plan of care or a new diagnosis, the physician must see the patient again before incident-to billing can resume.
• The NPP must be an employee, leased employee, or independent contractor of the practice. The business relationship must be properly established, and the NPP must be working under the supervision arrangement described above.

The Mistakes Most Practices Make

The requirements sound straightforward on paper, but in the daily chaos of a busy practice, violations happen constantly. Here are the patterns that OIG auditors and Medicare Administrative Contractors find most frequently:

Mistake 1: The Physician Never Saw the Patient

A new patient calls and gets scheduled with the nurse practitioner. The NP evaluates the patient, establishes a diagnosis, and creates a treatment plan. The practice bills the encounter under the physician’s NPI as incident-to. This is wrong. The physician never initiated the plan of care, which is a non-negotiable prerequisite. Every new patient problem or new diagnosis must be evaluated by the billing physician before subsequent NPP visits can qualify as incident-to for that condition.

Mistake 2: The Physician Is Not in the Office Suite

The physician left the office at 3 PM for a hospital round. The NP continues seeing patients until 5 PM, and those encounters are billed under the physician’s NPI. This is a direct violation of the direct supervision requirement. It does not matter that the physician was in the building earlier, was reachable by phone, or was at the hospital across the street. If the physician is not in the office suite at the time of the NPP’s service, incident-to billing is not available.

Mistake 3: Billing Incident-to for New Problems

A patient with an established plan of care for hypertension comes in and mentions a new knee pain. The NP evaluates the knee, orders imaging, and starts a treatment plan. The practice bills the entire encounter as incident-to. The hypertension follow-up component may qualify, but the knee evaluation does not — the physician did not establish the plan of care for that new problem. The new problem portion must be billed under the NPP’s own NPI at the 85 percent rate, or the patient must be seen by the physician to initiate that plan of care.

Mistake 4: No Documentation of Physician Involvement

Even when all the substantive requirements are met, the medical record must reflect the physician’s involvement. The chart should reference the physician’s established plan of care, the NPP should document that the physician was present in the office suite, and ideally the physician should periodically review and co-sign records for incident-to encounters. If the documentation reads as though the NPP independently managed the patient with no physician involvement, an auditor will not accept an after-the-fact assertion that the requirements were met.

The Financial and Legal Exposure

Improperly billing incident-to is not just an overpayment issue — it can constitute a false claim under 31 USC § 3729. If OIG or a Medicare Administrative Contractor audits your practice and determines that incident-to claims did not meet all requirements, you face repayment of the difference between the physician rate and the NPP rate for every non-qualifying claim, potential False Claims Act liability with treble damages, and possible exclusion from Medicare for repeated billing violations.

A qui tam (whistleblower) lawsuit from a disgruntled employee who knows the practice’s incident-to billing is non-compliant is one of the most common triggers for these investigations. The whistleblower receives a percentage of any recovery, creating a strong financial incentive to report. Practices that train staff properly and maintain compliant billing practices eliminate this risk entirely.

How to Get Incident-to Billing Right

Build these safeguards into your practice operations:

1. Track physician presence. Implement a daily log or scheduling system notation that records when the physician is physically present in the office suite. If the physician leaves mid-day, incident-to billing stops for all NPP encounters from that point until the physician returns.
2. Flag new problems at check-in. Train front desk and clinical staff to identify when a patient is presenting with a new complaint that the physician has not previously evaluated. Route those patients to the physician or bill the NPP encounter under the NPP’s NPI.
3. Audit incident-to claims quarterly. Pull a sample of claims billed under the physician’s NPI where the NPP provided the service. Verify that the physician initiated the plan of care, was present in the suite, and that the documentation supports the incident-to requirements. Include this in your compliance program’s auditing activities.
4. Educate every provider and biller. Providers and billing staff must understand the rules. A 15-minute in-service training with clear examples of what qualifies and what does not is far less expensive than an OIG investigation. Document the training and repeat it annually.
5. When in doubt, bill under the NPP. The 15 percent difference is never worth the compliance risk. If any element of the incident-to requirements is uncertain for a particular encounter, bill under the NPP’s NPI. You will receive 85 percent of the fee schedule with zero compliance exposure.

Telehealth and Incident-to: A Special Note

During the COVID-19 public health emergency, CMS temporarily relaxed certain incident-to supervision requirements for telehealth. As of 2026, the direct supervision requirement can be met through real-time audio-video communication for certain services, but this flexibility is subject to ongoing rulemaking. Verify the current CMS policy before relying on virtual supervision for incident-to billing. Do not assume pandemic-era flexibilities still apply without checking the current Medicare Benefit Policy Manual.