01-095 Mohs Surgery Findings of Medical Review

Noridian Healthcare Solutions, LLC, (Noridian), as the Supplemental Medical Review Contractor (SMRC) for the Centers for Medicare and Medicaid Services (CMS), has conducted post-payment review of claims for Medicare Part B Mohs Current Procedural Terminology (CPT) codes, 17312 and 17314, billed on dates of service (DOS) January 1, 2022, through December 31, 2022. Below are the review results:

Project ID Project Title Error Rate for Reviewed Claims No Response to ADR Denials
01-095 Mohs Surgery 5% 19%


Mohs micrographic surgery (MMS) is a specialized, tissue-sparing procedure for the surgical removal of complex or ill-defined skin cancer. The Mohs technique involves the surgical excision of the visible tumor followed by excision of a thin layer of normal appearing tissue surrounding the tumor. The excised tissue is immediately processed in an on-site laboratory for microscopic examination to identify whether any cancer cells are present. If cancer cells are present, additional excision and tissue evaluation are repeated until the margins are clear of cancer cells.

The initial excision and microscopic evaluation, considered the first stage of the Mohs procedure, are assigned CPT codes 17311 (Removal and microscopic exam of growth of head, neck, hands, feet, or genitals, 1-5 tissue blocks) or 17313 (removal and microscopic exam of growth of trunk, arms, or legs, 1-5 tissue blocks) depending on the location of the tumor being excised. CPT 17315 (Removal and microscopic exam of growth, each additional block after 5 tissue blocks) is an add-on code utilized when additional tissue blocks are needed beyond the 1-5 tissue blocks in the first stage. Add-on codes, CPT 17312 (Removal and microscopic exam of growth of head, neck, hands, feet, or genitals, each additional stage, 1-5 tissue blocks) and 17314 (Removal and microscopic exam of growth of trunk, arms, or legs, each additional stage, 1-5 tissue blocks) are billed when further excision is required for remaining cancer cells not cleared by the previous excision levels.

Reason for Review

The SMRC was tasked to perform data analysis and conduct a coding review for claims billed with the Mohs surgery add-on codes 17312 and 17314 with DOS January 1, 2022, through December 31, 2022.

The SMRC has conducted medical record coding reviews in accordance with applicable waivers/flexibilities/statutory, regulatory, and sub-regulatory guidance.

Common Reasons for Denial

  • Requested Records Not Received
    • Refer to Internet-only Manual (IOM) Published (Pub.) 100-08, Medicare Program Integrity Manual (MPIM) Chapter (Ch.) 3, Section (§), 42 Code of Federal Regulation (CFR) 424.5(a)(6), Social Security Act (SSA) 1862(a)(1)(A), SSA 1833(e). The MPIM 100-08, Ch. 3, § requires providers/suppliers to respond to requests for documentation within 45 calendar days of the additional documentation request for the dates of service under review. The documentation was not submitted or not submitted timely.
  • Number of Units Billed Not Supported
    • Refer to IOM, 100-08, MPIM Ch. 3, §§ and, Medicare Claims Processing Manual (MCPM) Pub. 100.04, Ch. 23. The documentation did not support the units as billed. Documentation submitted supported units less than or greater than units billed for the Mohs surgery add-on codes 17312 and 17314; therefore, the units were corrected.
  • Rendering Provider Billed on Claim Different than Rendering Provider in Documentation
    • Refer to IOM, MCPM, Pub. 100-04, Ch. 1 & 23. The documentation submitted supports the performing and billing providers are different. The rendering provider on the claim did not match the rendering provider who performed the Mohs procedure in the submitted documentation.


Social Security Act (SSA), Title XVIII

  • § 1815(a) Payment to Providers of Services
  • § 1833(e) Payment of Benefits
  • § 1861(s)(1) Physician Services
  • § 1861(s)(2) Services and Supplies
  • § 1861(s)(3) Medical and Other Health Services
  • § 1862(a)(1)(A) Exclusions from Coverage and Medicare as Secondary Payer
  • § 1879(a)(1) Limitation on Liability of Beneficiary where Medicare Claims are Disallowed
  • § 1893(b) Medicare Integrity Program

42 Code of Federal Regulations (CFR)

  • § 410.28 Hospital or CAH diagnostic services furnished to outpatients: Conditions
  • § 410.32(d)(2) Diagnostic x-ray tests, diagnostic laboratory tests, and other diagnostic tests: Conditions
  • § 410.64 Additional Preventative Services
  • § 411.15(k)(1) Any services that are not reasonable and necessary
  • § 424.5 Basic Conditions
  • § 493 Laboratory Regulations

Internet Only Manual (IOM), Medicare Benefit Policy Manual (MBPM), Publication (Pub.) 100-02

  • Chapter (Ch.) 6 § 20 Hospital Services Covered Under Part B
  • Ch. 15 § 30 Physician Services
  • Ch. 16 General Exclusion from Coverage

IOM, Medicare Claims Processing Manual (MCPM), Pub. 100-04

  • Ch. 1 General Billing Requirements
  • Ch. 12 § 20.3 Bundled Services/Supplies
  • Ch. 12 § 40-40.6 Surgeons and Global Surgery
  • Ch. 12 § 60 Payment for Pathology Services
  • Ch. 23 § 20.9 National Correct Coding initiative (NCCI)
  • Ch. 23 § Instructions for Codes with Modifiers (A/B MACs (B) Only)
  • Ch. 30 § 50.3 Financial Liability Protections

IOM, Medicare Program Integrity Manual (MPIM), Pub. 100-08

  • Ch. 3 Verifying Potential Errors and Taking Corrective Actions
  • Ch. 3 § Requested Records Not Received
  • Ch. 3 § Review Timelines Requirements
  • Ch. 3 § Signature requirements
  • Ch. 3 § Coding Determinations


  • Medicare National Correct Coding Initiative Policy Manual, Ch. 3 § F Mohs Micrographic Surgery Effective January 1, 2020, and January 1, 2021

Last Updated Mar 19, 2024