Why it matters. If your derm practice runs a steady Mohs and reconstruction schedule, an Ambulatory Surgery Center (ASC) can convert time on the scope into a second revenue stream via the facility fee, while keeping total system costs below hospital outpatient levels. The Medicare Payment Advisory Commission (MedPAC) finds ASC rates are ~46% lower than Hospital Outpatient Department (HOPD) rates for the same services, which is why payers like them; you still bill your professional fee separately under the Physician Fee Schedule. This means more control, better flow, and a real lift to practice economics if the volume is there.

Mohs bundling trips up even seasoned teams because the codes already pay for slide prep and interpretation. If you add surgical pathology on the same tissue, most payers will deny unless documentation proves it was a separate lesion or service. The safest guardrails are tight charge-capture rules and explicit note language that distinguish true add-on pathology from the Mohs chain. Medicare’s guidance and payer policies spell this out clearly for same-day Mohs plus pathology, including the limited scenarios where modifiers apply.

“All-inclusive” commercial ASC deals can quietly drain margin because the case rate often bundles routine supplies and equipment, and sometimes high-cost items, unless you carve them out up front. If your contract language is vague, you can end up paid the same rate whether you used minimal disposables or a cart full of pricey supplies. Use Medicare’s definition of what ASCs are expected to furnish as your baseline, then negotiate explicit carve-outs and rate tables for anything that materially moves case cost. Contracting playbooks and industry guidance emphasize auditing terms for bundled supplies and implant carve-outs before go-live, not after the first underpaid batch.

The regulatory clock is really three clocks. State licensure, CMS certification, and any certificate-of-need review run on different rails and timelines, and one slow track can idle a finished suite. Plan the sequence early, map document dependencies, and budget time for surveys tied to the ASC Conditions for Coverage. Also check your state’s CON status and recent changes; requirements vary widely and have been in flux in several states. Treat these paths as a critical path item in your project plan, not paperwork you can “catch up on” after construction.

Want benchmarks for Mohs case mix, payer rates, and expected denial patterns in ASCs vs office? Clarity can analyze your last 12 months of claims to show the gap and the upside.

This one was super fun. Hope you enjoyed it too.