Dermatology billing services
Mohs Surgery Billing and Coding
Mohs is the highest-value work in most dermatology practices and the least forgiving to bill. Stages and tissue blocks have to be sequenced correctly, repairs have to be separated from the surgical codes where the payer allows it, and a single missed add-on stage removes several hundred dollars from a case that has already been performed.
Stage and block sequencing
- 17311 and 17313 for the first stage on head/neck/hands/feet/genitalia and trunk/arms/legs respectively, with 17312 and 17314 applied per additional stage.
- 17315 for each additional block beyond five within any stage, which is routinely dropped when the surgeon's map is not reconciled against the claim.
- Stage counts reconciled against the Mohs map and the pathology log rather than taken from a checkbox.
- Correct handling when the surgeon acts as both surgeon and pathologist, and when a separate pathology consult is genuinely warranted.
Repairs, flaps and grafts after the excision
Reconstruction after Mohs is where most of the remaining money sits. Adjacent tissue transfers (14000–14302), skin grafts (15002–15760) and complex repairs each have their own defect-size measurement rules, and the defect measured is the post-excision defect, not the original lesion. We separate the reconstruction correctly, apply modifier 59 or the appropriate X modifier where the payer requires it, and know which payers bundle simple closure into the Mohs codes.
Payer rules and denial patterns we watch
- Medicare Administrative Contractor local coverage determinations that limit Mohs to specific tumour types, sites and clinical circumstances.
- Frequency and medical necessity edits when several stages are billed on the same date.
- Bundling edits between the Mohs codes and same-day pathology, closure and E/M services.
- Prior authorization requirements applied by some commercial plans before Mohs on lower-risk sites.
Frequently asked questions
Do you bill the reconstruction separately from the Mohs stages?
Yes, where the payer and the documentation support it. Simple closure is bundled by many payers, while intermediate and complex repairs, flaps and grafts are separately reportable with correct defect sizing.
How do you make sure no stage is missed?
Each case is reconciled against the Mohs map and the slide log before submission, so stage and block counts on the claim match the surgical record.
Can you bill for a Mohs surgeon who reads their own slides?
Yes. The Mohs codes already include the pathology component performed by the surgeon; we make sure a separate pathology charge is not added incorrectly, which is a common audit trigger.