CurrentHighmark Blueshield NenyPolicy N/A

Mohs micrographic surgery — coding, documentation, and billing guidance

Defines coding, documentation, and billing guidance for Mohs micrographic surgery (CPT 17311-17315) and related pathology codes for Highmark Blue Shield members; affects providers submitting claims in the listed service areas (includes state-specific notes).

Policy Summary

PayerHighmark Blueshield Neny

PolicyMohs micrographic surgery — coding, documentation, and billing guidance

Policy CodePolicy N/A

Change TypeNo material changes

Effective DateSep 1, 2024

Next Review DateN/A

Key ActionDo not report surgical pathology codes separately for tissue used for Mohs margin evaluation; document number of stages, number of blocks per stage, lesion details, and that the same physician performed surgery and pathology.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

17311-17315Mohs surgery codes referenced

88302-88309,88331-88332Pathology codes referenced

Stages/blocks/lesionDocumentation focus

DE/PA/WV/NYState cross-references

Mohs Coverage and Billing Criteria

Policy Summary

PayerHighmark Blueshield Neny

PolicyMohs micrographic surgery — coding, documentation, and billing guidance

Policy CodePolicy N/A

Change TypeNo material changes

Effective DateSep 1, 2024

Next Review DateN/A

SourceLink

On This Page

Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.

Mohs coverage and billing criteria

Coverage and billing stance for Mohs and associated pathology services:

Claims must be supported by documentation specifying lesion location, the number of stages required for each lesion, the number of blocks per stage, lesion size and complexity, and that the same physician performed both the surgical and pathology services.

Pathology CPT codes 88302-88309 and 88331-88332 representing pathologic examination should not be reported separately from Mohs surgical codes (CPT 17311-17315) when the tissue was used for margin evaluation during Mohs and the surgeon performs the pathologic examination.

Exceptions

If the Mohs surgeon submits specimen(s) from the procedure to another physician (pathologist) for frozen or permanent section, those pathology services may be reported separately by the receiving pathologist; in such situations the service provided by the receiving provider is not considered Mohs and appropriate excision/repair codes should be used by that provider.
When biopsy tissue is different from the tissue processed during Mohs, or when a diagnostic biopsy occurred prior to Mohs, modifier -59 may be appended to the pathology code to report the biopsy/frozen section separately.

Do not use modifier -59 to separate biopsy and Mohs when the submitted tissue is the same tissue processed during Mohs surgery.

Mohs and Related Pathology Coding & Documentation

Mohs surgical excision codesCPT

17311-17315	Mohs micrographic surgical excision codes (by lesion location/number of blocks)
88302-88309	Pathologic examination codes — generally not reported separately when used for Mohs margin evaluation
88331-88332	Additional pathology codes potentially used when specimens are sent to another pathologist
-59	Modifier -59 may be appended to pathology code when biopsy tissue is different from tissue processed during Mohs or when biopsy occurred prior to Mohs

Documentation threshold

Documentation requiredDocument number of stages, number of blocks per stage, lesion size/complexity, and that the same physician performed both surgical and pathology services

Lesion locationRecord specific lesion location as documentation supports CPT code selection by location

Block count basisDocument how many tissue blocks each stage was divided into (Mohs codes are based on number of blocks, not slides)

Stage countDocument the number of stages required to achieve clear margins for each lesion

Billing and Documentation Requirements for Providers

Billing Rule

Billing/documentation requirements for Mohs and pathology

Do not report surgical pathology CPT codes (88302-88309 or 88331-88332) separately from Mohs surgical codes (17311-17315) for tissue used for margin evaluation during Mohs; documentation must show the number of stages, number of blocks per stage, lesion size/complexity, lesion location, and that the same physician performed both the surgical and pathology services.

If specimens are sent to another pathologist for frozen or permanent section, the receiving pathologist may report pathology services separately; in that case the service is not considered Mohs for the receiving provider and appropriate excision/repair codes should be used.
Modifier -59 should not be used to separate biopsy and Mohs when the submitted tissue is the same as that processed during Mohs; -59 may be appended when the biopsy tissue is different or when a diagnostic biopsy occurred prior to Mohs.

Key Definitions

Stage (definition)

DefinitionStage: A single cycle of excision and microscopic examination during Mohs surgery; additional stages are performed until margins are clear

Role of surgeonThe surgeon excises tissue and acts as the pathologist examining mapped blocks during each stage

ProcessEach stage’s specimen is divided into blocks; blocks are mapped for location and microscopic evaluation

Block (definition)

DefinitionBlock: A portion of the excised specimen divided for mapping and microscopic examination within a stage

MappingEach block’s location within a stage is carefully mapped to guide further excision if cancer is found

Counting for codingMohs surgical CPT codes are built based on the number of required tissue blocks

Modifier -59 (Distinct procedural service)

When -59 may be appropriateModifier -59 may be appended to a pathology code when the biopsy tissue is different from the tissue processed during Mohs or when a diagnostic biopsy occurred prior to Mohs

When -59 is not appropriateDo not use modifier -59 to separate biopsy and Mohs when the submitted tissue is the same tissue processed during Mohs

ImplicationIf a Mohs surgeon sends specimens to another pathologist, the receiving pathologist may report pathology services separately rather than as Mohs