What this page covers
Dermatology billing services manage coding that turns on measurement and pathology: excisions (the 11400 and 11600 families) bill by excised diameter and malignancy, destructions (17000, 17110) bill by lesion count, and Mohs surgery (17311 to 17315) bills by stage and block. Because the Mohs surgeon reads the slides, separate pathology claims for the same specimens deny, and because payers scrutinize dermatology's modifier 25 volume, same-day E/M documentation carries real money. Biologics for psoriasis add step-therapy prior authorization on top. Flexbone runs eligibility, authorization, coding-agreement checks, and denial work for dermatology groups inside ModMed, Nextech, and your billing system.
How are lesion excisions and destructions coded?
Two measurements set the code, and one of them arrives days later. Excisions bill by excised diameter, the lesion plus its narrowest margins, so the size documented at excision decides the code within the benign (11400 to 11446) or malignant (11600 to 11646) family. Which family applies is the pathology report's call, which means a claim filed before pathology returns is a guess: a lesion excised as benign and read as malignant bills from a different series at a different rate. Destructions bill by count instead, with 17000, 17003, and 17004 for premalignant lesions and 17110 and 17111 for benign ones. Intermediate and complex repairs bill separately with excisions while simple repair is included. Flexbone holds the claim for the pathology read, checks size and family agreement, and routes what still denies through denials management.
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How does Mohs surgery billing work?
Mohs bills by geography, stage, and block. The first stage bills 17311 on the head, neck, hands, feet, and genitalia and 17313 on the trunk, arms, and legs; each additional stage bills 17312 or 17314, and 17315 covers each tissue block beyond the first five in a stage. The defining mechanic is that the Mohs codes pay for both the surgery and the pathology, because the same physician excises the tissue and reads the frozen sections. A separate pathology claim such as 88305 for the same specimens by the same physician denies as bundled. Same-day reconstruction is different: flaps, grafts, and intermediate or complex repairs bill separately once the margins are clear. Documentation must support the stage and block counts claimed. Flexbone verifies those counts and the repair coding inside ModMed EMA or your dermatology system before the claim files.
How do biologic authorization and medical necessity work in dermatology?
The biologic clinic runs on step therapy. Psoriasis, atopic dermatitis, and hidradenitis suppurativa drugs such as adalimumab, dupilumab, secukinumab, and risankizumab commonly require prior authorization documenting what was tried first: topicals, phototherapy, or conventional systemic agents, depending on the plan's policy. Renewals need response documentation, and a lapsed authorization stalls refills mid-course. The other necessity question is cosmetic versus medical. Payers cover lesion removal when the record documents symptoms or clinical suspicion, such as change, bleeding, irritation, or inflammation, and treat undocumented removals as cosmetic and patient-pay, so the note decides the coverage. Modifier 25 draws the same documentation scrutiny, since a skin check that turns into a destruction visit bills both an E/M and a procedure. Flexbone assembles the step-therapy history and submits the requests; the dermatology and plastics PA page covers the criteria.
How does Flexbone run dermatology billing?
Flexbone deploys browser and voice agents across the dermatology revenue cycle. Agents verify eligibility before the visit, submit and track the biologic authorizations and their renewals, hold excision claims for the pathology read and check size, family, and modifier agreement before they file, and work the denial queue by CARC code inside ModMed, Nextech, or your billing system. The front-office side, the high-volume scheduling and annual skin-check recall the specialty depends on, is covered on the AI for dermatology page. Results write back with an audit trail, and exceptions route to your billers with the context attached, which keeps staff attention on the appeals that need a clinical argument rather than the corrections that do not.