Understanding APP Incident-to Billing: A Dermatology Compliance Guide (2026)
If your dermatology practice bills Advanced Practice Provider (APP) visits — meaning PA or NP visits — at 100% of the physician rate through incident-to billing, this post is for you. Specifically: this post is for the biller, practice administrator, or physician who wants to know whether their incident-to claims will survive an audit. For background on what a compliant Good Faith Estimate needs to include, see our GFE compliance guide — incident-to status affects the rate used in that estimate.
Because here's the honest truth: most dermatology practices billing incident-to today are doing it wrong. Not because their billers are careless. Because the rules are more restrictive than most people realize, and Medicare has been increasing scrutiny on APP claims year-over-year.
Let's walk through it.
The 85% vs 100% Question
Under Medicare Part B, APP visits (PA and NP services) can be billed two ways:
Option 1: Own NPI at 85% of the physician fee schedule. The APP bills under their own National Provider Identifier. Medicare reimburses at 85% of what the physician would be paid for the same service.
Option 2: Incident-to under the physician's NPI at 100%. The visit is billed under the supervising physician's NPI, and Medicare reimburses at the full physician rate — but only if the visit meets seven specific criteria.
The financial difference matters. On a $150 established patient office visit, the 85% rate is $127.50 vs the 100% rate at $150. Across a busy APP schedule seeing 20 patients per day over roughly 20 working days a month, that's $450 per day, $9,000 per month, or roughly $108,000 per year in reimbursement difference per full-time APP.
Which is why practices default to incident-to whenever they can. But that's exactly where the audit risk lives.
The 7 Rules for Legitimate Incident-to Billing
To legitimately bill an APP visit incident-to at 100%, ALL seven of the following must be true:
1The physician must have personally seen the patient and established the diagnosis and plan of care for the specific condition being treated. This applies whether the patient is new to the practice or an existing patient presenting with a condition the physician hasn't yet evaluated. An APP cannot independently establish a new diagnosis and then bill that visit — or any follow-up visit for that same condition — incident-to. This is the most commonly violated rule.
2The physician must be physically present in the office suite during the APP visit. Not on-call. Not in a different building. Not doing telehealth from home. Physically in the same office suite. If your supervising physician steps out for lunch and the APP sees a patient during that window, that visit cannot be billed incident-to.
3The APP must be treating the same established condition addressed by the physician. If the patient was seen by the physician for acne and comes back to see the APP for a suspicious mole, that new problem cannot be billed incident-to. It requires either a physician visit or an APP visit billed under the APP's own NPI at 85%.
4The physician must have an established employment or contractor relationship with the APP. The APP must be an employee of the practice or under a contract that Medicare recognizes for supervision purposes. Rented office space with independently-contracted APPs generally does not meet this bar.
5The medical record must clearly document the supervising physician. The APP's chart note must name the specific supervising physician who was on-site and available during the visit. "Dr. Smith supervising" with no other documentation is often insufficient — auditors look for evidence the physician was actually available.
6New problems trigger a new physician visit. If the patient develops a new symptom, new condition, or presents with something outside the established plan of care, the APP cannot independently expand the treatment plan and bill incident-to. Medicare expects the physician to re-establish care for the new issue.
7Medicare Part B only — most Medicare Advantage plans and commercial payers do not follow the same rules. Incident-to is a Medicare Part B billing convention. Medicare Advantage plans, commercial payers, and Medicaid MCOs each have their own rules — and many do NOT allow incident-to billing at 100% at all. Check every payer's provider manual.
Why Most Practices Get This Wrong
In seven years working across dermatology practices, I've seen the same three patterns:
Pattern 1: Defaulting to incident-to as the norm, then justifying after the fact. The APP schedule is full of established patients seeing the APP for their ongoing skin exams and biopsies. Nobody stops to ask "was this patient's most recent physician visit for THIS specific condition?" The claim goes out at 100%. If audited, the practice discovers half those visits should have been billed at 85%.
Pattern 2: Front desk not tracking who saw the patient first. When a new patient is scheduled with an APP, nobody flags that the physician needs to see them first for incident-to to ever apply. The APP sees the patient, establishes the plan, and the practice bills incident-to on every future visit. That first APP-only encounter disqualifies the entire chain of incident-to claims.
Pattern 3: Supervising physician documentation is a rubber stamp. The chart note says "Dr. Smith supervising" on every APP visit for five years, including on days Dr. Smith wasn't in the office. Auditors compare payroll and calendar records to chart notes and find gaps. This is a criminal fraud pattern in the worst cases and a straight denial-plus-clawback in the best.
Documentation Best Practices
If you want to defend your incident-to billing under audit, your documentation needs to answer three questions for every visit:
Question 1: Was the physician physically present in the office suite during this visit? Best practice: reference the physician's schedule in the note ("Dr. Smith on-site 8am-12pm, patient seen at 10:15am") or automate a scheduler-note linkage.
Question 2: What was the established diagnosis being addressed? Best practice: reference the physician's prior visit note ("established plan of care per Dr. Smith visit on 6/12/2026") explicitly, not generically.
Question 3: Did any new problem arise during this visit that would require physician involvement? Best practice: if yes, document that a physician was consulted or the patient was scheduled back to see the physician for the new issue.
When You Should NOT Bill Incident-to
Even if you technically CAN bill incident-to, sometimes it's not worth the audit risk. Consider defaulting to APP own-NPI at 85% when:
- The visit addresses multiple problems, some of which the physician hasn't seen the patient for
- The supervising physician's schedule that day is unclear or has gaps
- The chart documentation isn't complete enough to defend under audit
- The patient's insurance is a Medicare Advantage plan that doesn't honor incident-to (many don't)
The math to remember: The 15% revenue difference on one visit is small. The audit exposure of a systematic pattern of improper incident-to billing across thousands of claims is not.
How DermEstimator Helps
DermEstimator handles APP billing math directly. When you build a patient cost estimate, you select which provider will see the patient. If the APP is going to see them and you're billing incident-to, the estimator applies the 100% rate. If billing own-NPI, it applies 85%. Payer-specific rates are respected — so if a specific Medicare Advantage plan doesn't honor incident-to at all, the estimator defaults to 85% for that payer automatically. See the full breakdown on our features page.
This gets the estimate right at the front desk. But the audit-risk question — did we actually MEET all 7 criteria for this specific visit? — is a documentation and workflow question your practice has to solve. The estimator gets you a defensible starting point; the seven rules get you an audit-defensible practice.
If your billing team wants to walk through incident-to scenarios in plain English, the DermEstimator AI Coding Assistant answers billing questions grounded in our own dermatology fee schedule — try it on Derm Pro.
The Bottom Line
Incident-to billing at 100% is a legitimate reimbursement pathway for dermatology practices when the rules are followed. But defaulting to it without validating the 7 criteria on every visit is one of the biggest sources of Medicare clawback risk in the specialty right now.
Most practices are either leaving APP revenue on the table (defaulting to 85% to be safe) or carrying silent audit risk (defaulting to 100% without documentation). Neither is the right answer. The right answer is a workflow that identifies which visits qualify, documents them properly, and defaults to 85% when any of the 7 criteria are in doubt.
Save this guide for your next practice-wide compliance review. Send it to your billing team. If you want an APP billing audit — where I personally review one month of your APP claims and flag revenue leakage or audit exposure — that's included as a bonus for founding practices at DermEstimator.
Educational information only. This article is not a substitute for review by qualified coding/compliance staff or legal counsel. Verify current CMS incident-to policy and your specific payer contracts before changing a billing workflow.
Claim your APP Billing Audit
I'll personally review one month of your APP claims and flag revenue leakage or audit exposure — included as a bonus for founding practices at DermEstimator.
Claim your APP Billing Audit →Juhi Mirchandani is the founder of DermEstimator, an AI-powered patient cost estimator built specifically for dermatology practices. She spent 7 years in dermatology operations — medical assistant, clinical coordinator, biller, and office manager — before building DermEstimator to solve the problems she watched every practice fight with daily.