CPT 17311: Mohs surgery, first stage, head and neck
17311 reports the first stage of Mohs micrographic surgery for sites in the head and neck group, with the same physician acting as surgeon and pathologist. The code already includes the pathology of that stage, so frozen sections are not billed on top of it.
Written by Salman Saeed, CEO and Co-Founder · Reviewed by a Certified Medical Coder · Last reviewed October 2026In short: 17311 is a 000-global first-stage code, 17312 adds each later stage, and 17315 adds each extra tissue block. NCCI says the Mohs codes include the excision and the pathology services, and Medicare prices 17311 with the standard multiple surgery rules.
What does CPT 17311 report?
17311 is the first stage of Mohs micrographic surgery on the head and neck group of sites. The CMS file labels it "Mohs 1 stage h/n/hf/g" and the trunk, arm and leg code 17313 "Mohs 1 stage t/a/l". NCCI Chapter III describes Mohs surgery as the removal of a complex or ill-defined skin cancer where a single physician performs both the surgery and the pathologic examination.
| Code | CMS label | Work RVU | Global | MUE (Q4 2026) |
|---|---|---|---|---|
| 17311 | Mohs 1 stage h/n/hf/g | 6.05 | 000 | 4 |
| 17312 | Mohs addl stage | 3.22 | ZZZ | 6 |
| 17313 | Mohs 1 stage t/a/l | 5.42 | 000 | 3 |
| 17314 | Mohs addl stage t/a/l | 2.98 | ZZZ | 4 |
| 17315 | Mohs surg addl block | 0.85 | ZZZ | 15 |
The add-ons are billed with their first-stage code on the same claim. 17312 follows 17311, 17314 follows 17313, and 17315 can be added for each tissue block beyond the first. Each stage and block count needs its own line in the operative note.
Can I bill pathology with Mohs surgery?
No, not for the same stage. NCCI Chapter III says the Mohs codes include the skin biopsy and excision services (11102 to 11107, 11600 to 11646 and 17260 to 17286) and the pathology services 88300 to 88309 and 88329 to 88332, and that reporting those codes in addition to Mohs is inappropriate. Frozen-section codes such as 88331 and 88332 are inside the Mohs payment.
The exception is a biopsy done first. If a suspected skin cancer is biopsied for diagnosis before the Mohs procedure, the biopsy (for example 11102) and its frozen section can be reported separately with modifier 59, XS or XU, or with modifier 58 to show the services were staged or planned. The manual says the CPT book names 59 but accepts 58. See modifier 59.
Immunohistochemistry is treated differently. Chapter III says the Mohs surgeon reports one unit of 88342 per specimen for an initial single-antibody stain, and 88341 for each additional different stain, one unit per stain. Repairs, grafts and flaps after Mohs are separately reportable.
Does 17311 take modifier 51?
Medicare prices it under the standard multiple surgery rules. RVU26D gives 17311 a multiple procedure indicator of 2, so on the same day as other surgery by the same physician, Medicare ranks the procedures by fee schedule amount and pays 100% for the highest and 50% for the second through fifth. The ASC addendum also marks 17311 as subject to multiple procedure discounting.
Claims Processing Manual chapter 12, section 40.6, says to report the more major procedure without modifier 51 and the additional procedures with it. Medicare identifies multiple surgeries by the modifier and also by more than one payable surgery billed for the same patient and day, so leaving it off does not avoid the reduction. Which codes the CPT book exempts from modifier 51 matters mainly for other payers, so check each contract.
How does 17311 appear on the claim?
On the CMS-1500, Item 24D carries 17311 and Item 24G carries the units, within the MUE of 4. Item 24E points to the skin cancer diagnosis, and Item 24B is 11 for an office, 22 or 19 for a hospital outpatient department, or 24 for an ambulatory surgery center. Later stages go on their own lines with 17312 and 17315, and a repair line is added when one was done.
In the ASC addendum 17311 has payment indicator P2, an office-based surgical procedure added to the ASC list with payment based on the OPPS weight. The dermatology billing page shows how Mohs fits with biopsy and destruction codes, and CPT 17000 covers the premalignant lesion code.
Where do stages and tissue blocks go for 17311?
Mohs surgery is billed per stage. The first stage on the head, neck, hands, feet or genitalia is 17311 in Item 24D with 1 unit in Item 24G, and later stages go on their own line. Item 24E points to the skin cancer diagnosis, and the number of tissue blocks belongs in the note and the pathology section.
RVU26D gives 17311 status A, a 000 global and multiple-procedure indicator 2. The MUE table allows 4 per date with indicator 3 and a clinical rationale, which is about the number of stage units, not a promise that four will pay.
Example: A basal cell carcinoma of the nose takes two stages on 10/22. The claim shows 17311 with 1 unit, pointer A (C44.311), $1,850.00, and the second-stage add-on line with 1 unit at $720.00. Each stage has a map and a margin result in the note.
Why is 17311 denied?
| CARC | What X12 says | What usually causes it |
|---|---|---|
| 97 | The benefit is included in the payment for another service already adjudicated | Frozen section 88331 or a biopsy billed with the same stage |
| 236 | The procedure combination is not compatible with another on the same day under NCCI | Excision or destruction codes reported with Mohs |
| 151 | The information submitted does not support this many or this frequency of services | More than 4 units of 17311, or stage and block counts above the MUEs |
| 4 | The procedure code is inconsistent with the modifier used | Modifier 59 or XS on a biopsy with no separate site or earlier encounter |
| 11 | The diagnosis is inconsistent with the procedure | A benign or unspecified lesion diagnosis on a Mohs line |
If these denials keep coming back, our denial management team can work them.
Related codes
- Physician Fee Schedule relative value files, RVU26D (October 2026) · CMS
- Medicare NCCI Medically Unlikely Edits, practitioner and outpatient hospital tables, effective 10-01-2026 · CMS
- ASC payment rates and addenda, October 2026 Addenda AA and DD1 · CMS
- 2026 NCCI Medicare Policy Manual, Chapter III: Integumentary System · CMS
- Medicare Claims Processing Manual, Chapter 12: Physicians/Nonphysician Practitioners · CMS
- Medicare Claims Processing Manual, Chapter 26: Completing and Processing Form CMS-1500 Data Set · CMS
- Claim Adjustment Reason Codes · X12
- Place of service code set · CMS
We check every rule, code and deadline against the official source. See our editorial policy.
Common questions
Straight answers from the team that does the work.
Ask a billing lead directly. A 20-minute call, Monday to Friday, 9am to 5pm Eastern.
01How do I bill each stage of Mohs surgery?
Bill 17311 for the first stage on the head and neck group, with 17312 for each later stage, or 17313 and 17314 for the trunk, arms and legs. Add 17315 for each tissue block beyond the first. Each add-on needs its own line and a matching operative note.
02Can I bill a frozen section with 17311?
Not for the Mohs stage. NCCI Chapter III includes pathology services 88300 to 88309 and 88329 to 88332 in the Mohs codes. A biopsy taken earlier to diagnose the cancer, with its frozen section, can be reported separately with modifier 59, XS, XU or 58.
03Does a same-day biopsy bill separately from 17311?
Only when it was a diagnostic biopsy done before the Mohs procedure. NCCI Chapter III allows the biopsy and its frozen section with modifier 59, XS, XU or 58 to mark them as distinct from the definitive Mohs surgery. A biopsy that is part of the Mohs work is not billed.
04Does 17311 take modifier 51?
Chapter 12 says to report the main procedure without 51 and additional procedures with it. RVU26D gives 17311 a multiple procedure indicator of 2, so Medicare ranks it by fee schedule amount and applies the standard reductions whether or not the modifier is on the line.
05Are repairs billed with Mohs surgery?
Yes. NCCI Chapter III says repairs, grafts and flaps are separately reportable with the Mohs codes. The chapter also says simple, intermediate and complex wound repair codes may be reported with 17311 to 17315, so the repair gets its own line.
06How many units of 17311 can I bill?
Up to 4 per date of service. The NCCI MUE for 17311 effective October 1, 2026 is 4 in the practitioner and outpatient hospital tables, with indicator 3, a clinical edit. Later stages use 17312, whose MUE is 6, and extra tissue blocks use 17315, whose MUE is 15.
Mohs claims denied for pathology or bundling?
We match each stage, block and biopsy to the note before the claim goes out.