CPT Code 17311: Mohs Micrographic Surgery, First Stage, Head/Neck/Hands/Feet/Genitalia

CPT code 17311 is for Mohs micrographic surgery for skin cancer removal in high-risk areas. Read about its billing and documentation guidelines here.

Use Code

What is CPT code 17311?

CPT code 17311 is used to report Mohs micrographic surgery for the first stage of excision in high-risk anatomical locations, including the head, neck, hands, feet, and genitalia. It covers up to five tissue blocks and includes both the surgical removal of the lesion and the microscopic examination of tissue margins by the same physician.

This primary procedure is commonly used in treating skin cancer, such as basal cell carcinoma and squamous cell carcinoma, where precision and tissue conservation are critical. CPT 17311 requires that the provider acts as both the surgeon and the pathologist, performing all services on the same date, and cannot be reported if pathology services are performed by a different provider.

To determine reimbursement rates for CPT 17311, consult the Medicare Physician Fee Schedule published by Medicare Administrative Contractors. These entities are responsible for applying national coverage rules and handling payments under the Medicare Physician Payment Schedule.

What is Mohs micrographic surgery?

A Mohs procedure is a staged surgical approach used primarily to treat certain skin cancers, including basal cell carcinoma and squamous cell carcinoma. The provider removes cancerous tissue layer by layer, and each layer is immediately assessed under a microscope to check for malignancy in the margins. This technique ensures complete tumor excision with minimal loss of healthy tissue. It is especially useful in cosmetically sensitive or functionally important areas, such as the face or hands.

CPT code 17311 documentation requirements

To properly report CPT 17311, providers must meet specific documentation standards to support medical necessity and ensure compliance.

Pre-op diagnosis and lesion location

Include the clinical diagnosis (e.g., basal cell carcinoma) and exact anatomical site, noting that this code applies only to specific areas like the face, scalp, or genitalia.

Medical necessity for Mohs

Document the rationale for choosing Mohs surgery over traditional excision, commonly due to high-risk histologic subtypes, recurrent lesions, or location in critical areas.

Number of stages and tissue blocks

Indicate that this service represents the first stage and include the number of tissue specimens (up to five) removed and evaluated.

Operative note with diagram and findings

Include an operative report detailing each stage with annotated diagrams, pathology report summaries, and microscopic examination findings to verify margin status.

Surgeon must serve as both excising and interpreting physician

Per Mohs surgery codes, the same provider must perform both the excision and histologic interpretation to meet the criteria of CPT 17311. This is a specific code requirement.

CPT Code 17311 Billing Guidelines

Correctly reporting 17311 CPT code involves following several billing and compliance rules to ensure appropriate reimbursement.

Use only for the first stage

CPT 17311 covers the first stage of the Mohs procedure, including removal and interpretation of up to five tissue blocks.

Use 17312 for additional stages

If additional stages are needed to fully remove the lesion, report 17312 for each subsequent stage.

Pathology services are included

Do not separately bill for pathology services, as the interpretation is integral to the Mohs procedure. These are not separately reimbursable.

Avoid duplicate billing

Do not bill separately for excision, closure, or pathology services unless the services are distinct and separately reportable, with documentation to justify modifier use.

Applicable modifiers for CPT code 17311

In some cases, appropriate modifiers are necessary to clarify the nature or scope of services performed. Below are commonly used modifiers for Mohs surgery billing:

Modifier 25: Use when a significant, separately identifiable evaluation and management (E/M) service was provided on the same day.
Modifier 59: Use when Mohs surgery is distinct from another procedure, like a biopsy performed at a different site.
Modifier XS: Identifies a separate structure or organ when required by payers in place of Modifier 59.
Modifier 76: Use if the same provider repeats the procedure on the same day.
Modifier 77: Use if a different provider repeats the procedure.
Modifier 78: Report for an unplanned return to the operating room during the postoperative period for a related service.
Modifier 79: Use for unrelated services performed by the same physician during the post-op period (though Mohs codes have zero global days).
Modifier 58: Indicates a staged or related procedure during the postoperative period.
Modifier 22: Report when the Mohs surgery required significantly more work than typical.
Modifier 52: Use if the procedure was partially reduced.
Modifier 53: Indicates a discontinued procedure due to complications.
Modifiers 54, 55, 56: Denote surgical care only, postoperative management only, or preoperative management only, respectively.
Modifiers 62, 66: For procedures requiring two surgeons or a surgical team.
Modifiers 80, 81, 82, AS: Used when assistants (including qualified healthcare professionals such as nurse practitioners or physician assistants) assist in surgery.

Other relevant CPT codes

Several other Current Procedural Terminology codes are closely related to CPT code 17311:

17312: Mohs micrographic technique, each additional stage after the first stage, same anatomic area (add-on code).
17313: Mohs micrographic technique, first stage, trunk, arms, or legs.
17314: Mohs micrographic technique, each additional stage after the first stage, trunk, arms, or legs (add-on code).
17315: Mohs micrographic technique, each additional tissue block, after the first 5 tissue blocks, any human or animal tissue specimen, any stage (add-on code).
131XX series (e.g., 13131-13153): Complex repair codes. These are typically used when complex wound closure is performed and documented as a separate and distinct procedure following Mohs surgery.