Payer guide · Medicare Advantage
Medicare Advantage Dermatology Billing: Prior Auth and Plan Rules
Medicare Advantage plans must cover what Medicare covers, but they are free to add utilization management on top of it. In dermatology that shows up as prior authorization on procedures traditional Medicare pays without one, tighter site-of-service rules, and appeal timelines run by the plan rather than the MAC. Practices that treat Advantage as Medicare with a different card find out at the remittance.
Where Advantage diverges from traditional Medicare
- Prior authorization on Mohs, on some excisions, and routinely on biologics and phototherapy.
- Referral requirements on HMO products, where a missing referral denies the whole encounter rather than one line.
- Narrow networks that exclude the pathology lab the practice has always used, moving the balance to the patient.
- Plan-specific coverage policies for benign lesion removal that are stricter than the MAC's LCD.
Getting authorization right before the patient is roomed
The authorization must match what is actually performed. An approval for one CPT code does not cover the code billed when the stage count or lesion count changes intraoperatively, and the retroactive request is the one that fails.
Record the authorization number, the approved codes, the approved units and the valid date range in the chart, not in an email thread. Most authorization denials we see are appealable because an approval existed and could not be produced quickly enough.
Appeals run on the plan's clock
Each plan sets its own reconsideration window and its own escalation path, and the windows are frequently shorter than commercial equivalents. A denial that sits in a monthly sweep can be time-barred before anyone reads it.
Track appeal deadlines per plan rather than as a single internal policy, and escalate to the independent review level where the plan's own reconsideration keeps upholding a coverage reading that contradicts Medicare policy.
Frequently asked questions
Does Medicare Advantage have to follow Medicare coverage rules?
Plans must cover Medicare-covered services, but may apply their own prior authorization and utilization management, and may add clinical criteria beyond the MAC's.
Our authorization was approved and the claim still denied. Why?
Usually a mismatch — a different code, more units, a different rendering provider or a date outside the approved range. All are appealable when the approval is documented.