Dermatology billing and revenue cycle, 50-state coverage.

Mohs is billed by stage and by tissue block rather than as a single procedure. The first stage carries its own code, each additional stage of the same site carries another, and the block count on each stage matters. Two things go wrong in practice. The first is reconstruction of the stage log after the case instead of during it, which loses stages and blocks. The second is folding a same-day repair into the Mohs code, when the repair is a separately reportable service. Both are settled by how the case is documented while it is running, not by anything the billing office can do afterward.

By method and by measurement, both taken from the note. The method has to be explicit, since a shave, a destruction and a full-thickness excision are three different services that can look similar in loose documentation. The measurement has to be the lesion diameter plus the narrowest margin, recorded before the tissue is cut. Practices that measure from the specimen or take the size off the pathology report bill a smaller code than the work they performed, because tissue shrinks after excision. That single habit is one of the most reliable sources of underbilling in dermatology.

When the record shows a significant, separately identifiable evaluation and management service that stands on its own apart from the procedure performed the same day. In dermatology this is genuinely common, because a patient presenting for one complaint frequently needs a full skin evaluation. The problem is documentation, not clinical reality. A single blended note that describes the visit and the procedure together cannot support the modifier, even when the work was done. Keeping the evaluation and the procedure in distinct sections of the note is what makes the claim defensible on the day it is billed and years later if it is reviewed.

Split correctly, per specimen. A routine skin specimen sent for gross and microscopic examination has a professional component, the interpretation, and a technical component, the lab work and the equipment. If the practice owns the lab and an outside dermatopathologist reads the slide, it bills the technical component only. If the practice does both, it bills globally. Practices with in-house labs that default to a single billing habit across all specimens will be wrong on a meaningful share of them, and CLIA obligations sit alongside all of this.

At scheduling, with separate consent and a separate financial policy, not at the billing desk. Cosmetic surgery is excluded from Medicare coverage by statute and is treated the same way by most commercial plans, so cosmetic services are cash-pay by definition and never belong on a claim. The two failure modes are opposite and both expensive: a cosmetic service that reaches a payer is a compliance exposure, and a medically necessary service written off as cosmetic is revenue the practice earned and never billed. The hard case is a medical finding discovered during a cosmetic visit, which needs a written same-visit rule rather than an on-the-spot judgment call.