CPT 17312Surgery

Mohs addl stage

CPT code 17312 represents each additional stage of Mohs micrographic surgery beyond the first stage. This is a specialized skin cancer removal technique where the surgeon removes tissue layer-by-layer, examining each under a microscope until all cancer is removed.

Showing rates for

National Average

Base Medicare rate

$399.48

This calculator gives a typical-case estimate using standard Medicare modifier rules. Actual payment depends on payer policies, documentation, code-specific CMS status indicators, and locality. Verify before billing.

RVU breakdown

Work RVU

3.3

PE RVU (NF)

8.7

MP RVU

0.35

Total RVU

12.35

Conversion factor: 32.3465 · Source: CMS MPFS RVU25A · Confidence: High

NCCI bundling edits

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Billing tips

Document each stage separately with distinct specimen mapping, tissue processing time, and margin assessment findings
Impact: Critical for audit defense; each additional stage generates $399.48 in non-facility reimbursement
Bill the first stage with CPT 17311 before billing any 17312 codes; 17312 is an add-on code that cannot stand alone
Impact: Prevents automatic denial; 17312 will reject if billed without a primary Mohs code on the same date of service
Verify that operative notes clearly document that all surgical margins were examined for each stage
Impact: Medicare and commercial payers require complete margin assessment; incomplete documentation can result in $399.48 denial per stage
Use appropriate anatomic site designation from the primary code (17311-17315) and match all additional stages to that site
Impact: Inconsistent site coding triggers edits; ensures stages are properly attributed to the correct tumor location
Track and document time stamps for each stage's tissue processing and microscopic examination
Impact: Supports medical necessity for multiple stages and Work RVU value of 3.3; helps justify same-day billing of 4+ stages
For multiple tumors on the same day, ensure each tumor has its own first stage code (17311-17315) before billing corresponding 17312 codes
Impact: Proper sequencing prevents bundling; allows billing multiple sets of stages when treating 2-3 separate tumors in one session

Common denials

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Frequently asked questions

How many times can CPT 17312 be billed in one day?

CPT 17312 can be billed multiple times per session based on clinical necessity. There is no specific limit, but each additional stage must be medically necessary and fully documented. Most cases require 1-3 additional stages (2-4 total stages), though complex cases may require more. Payers may scrutinize claims with 5+ total stages.

What is the difference between CPT 17311 and 17312?

CPT 17311 is the first stage of Mohs surgery for head, neck, hands, feet, genitalia, or any location with diameter 2.0 cm or less, while 17312 represents each additional stage after the first. 17311 is a primary code billed once per tumor, whereas 17312 is an add-on code billed for each subsequent stage needed to achieve clear margins.

Does Medicare pay for CPT 17312 in office settings?

Yes, Medicare pays $399.48 for CPT 17312 in non-facility (office) settings and $182.76 in facility settings for 2025. The non-facility rate is significantly higher because it includes practice expense for maintaining histopathology equipment and supplies in the office.

Can CPT 17312 be billed for different tumors on the same day?

Yes, but each tumor requires its own first stage code (17311-17315) followed by the appropriate number of 17312 codes for that specific tumor. Use modifier 59 or XS to distinguish additional stages for separate tumors to prevent bundling denials.

What documentation is required to bill CPT 17312?

Documentation must include specimen mapping, confirmation that all surgical margins were examined microscopically, frozen section findings showing positive margins from the previous stage, and clear identification of the stage number. Each stage requires separate documentation showing tissue excision, processing, and complete margin assessment.

How much is CPT 17312 reimbursed by Medicare in 2025?

Medicare pays $399.48 for CPT 17312 in non-facility settings and $182.76 in facility settings based on the 2025 Physician Fee Schedule. The code has 12.35 total RVUs (3.3 work RVU, 8.7 non-facility PE RVU, 2.0 facility PE RVU, and 0.35 malpractice RVU).

What happens if margins are still positive after multiple stages of Mohs surgery?

Continue documenting and billing CPT 17312 for each additional stage until clear margins are achieved or the surgeon determines that further staging is not feasible. If surgery must be discontinued before clear margins, document the clinical rationale and plan for alternative treatment. Each stage performed should be billed regardless of final outcome.