Pathology/Lab Coding Alert

Steer clear of 17311-+17315.

Mohs micrographic surgery might result in billable pathology services, but then again, it might not.

Check out the following expert advice to uncover Mohs opportunities and pitfalls, with a dose of wisdom to know the difference.

Know Mohs Basics

In its purest form, Mohs is a skin-cancer treatment procedure involving both the surgical tumor excision (performed in stages to spare non-tumor tissue) and the pathology diagnosis/margin exam. Generally carried out by a dermatologist with special Mohs training, a true Mohs procedure provides almost no billing opportunity for pathologists.

Codes: The dermatologist will bill Mohs using codes in the range 17311-+17315 (Mohs micrographic technique, including removal of all gross tumor, surgical excision of tissue specimens, mapping, color coding of specimens, microscopic examination of specimens by the surgeon, and histopathologic preparation including routine stain(s) (eg, hematoxylin and eosin, toluidine blue) …).

Site: CPT^® distinguishes the codes based on anatomic site (17311-+17312 for … head, neck, hands, feet, genitalia, or any location with surgery directly involving muscle, cartilage, bone, tendon, major nerves, or vessels; and 17313-+17314 for … trunk, arms, or legs...)

Stages: CPT^® further distinguishes the codes based on stages. A “stage” is each excision and pathology exam the dermatologist performs to see if all tumor has been removed for a specific lesion. The dermatologist might need to complete several stages to reach an endpoint with all margins clear.

Blocks: Each add-on code (+17312, +17314, and +17315) accounts for an additional five tissue blocks per stage (if the stage requires more than the five blocks included in the base code 17311 or 17313).

Alert: “The Mohs codes include the histopathology tumor diagnosis using H&E stained slides and the frozen-section margin exam,” emphasizes R.M. Stainton Jr., MD, president of Doctors’ Anatomic Pathology Services in Jonesboro, Ark.

Bundling issues: Because the 17311-+17315 codes include the pathology exam(s), you cannot bill 88305 (Level IV - Surgical pathology, gross and microscopic examination … Skin, other than cyst/tag/debridement/plastic repair …) or 88331-+88332 (Pathology consultation during surgery; … tissue block, with frozen section(s) …) in addition to the Mohs codes for any tissue from the Mohs procedure.

Recognize 1 Mohs Plus Biopsy Exception

Sometimes pathology will evaluate a skin biopsy the same day as a Mohs procedure, and you can separately bill that service only under certain specific circumstances.

For instance, a Medicare Mohs coverage determination acknowledges that “a biopsy of the skin lesion for which Mohs surgery is planned is necessary in order for the physician to determine the exact nature of the lesion(s) to be removed.” Therefore, you can separately bill for a separate skin biopsy of the Mohs lesion on the same date when:

• the lesion for which Mohs surgery is planned has not been biopsied within the previous 60 days; or
• the surgeon cannot obtain a pathology report, with reasonable effort, from the referring physician.

Also: “When the pathologist examines a biopsy for a separate lesion that is not associated with the Mohs surgery on the same day, you can bill the pathologist’s biopsy exam,” says Peggy Slagle, CPC, coding and compliance manager for Regional Pathology Services at the University of Nebraska Medical Center in Omaha.

Do this: Append modifier 59 (Distinct procedural service) or equivalent modifier to the 88305 or 88331 service to garner pay for appropriate, documented skin-lesion pathology work on the same date as a Mohs procedure.

Seek Pathology Billing in ‘False’ Mohs

Not everything that seems like Mohs warrants using the Mohs codes. The following two clinical situations may occur that preclude billing Mohs codes:

Modified Mohs: Sometimes the dermatologist does the lesion excision and sends the “debulking” specimen (the main body of the tumor) for histopathology to confirm the tumor diagnosis. The dermatologist may also send the frozen sections to the pathologist for frozen section margin exam. When the dermatologist does not perform the pathology, the case is considered a “modified Mohs,” and the Mohs codes are not appropriate.

Slow Mohs: For certain lesions that may require more rigorous histopathology to diagnose and stage the tumor, such as melanoma in situ (MIS), the dermatologist may excise the tumor in stages and send all tissue to pathology.

The pathologist may examine permanent H&E slides of both the debulking specimen and each excised margin.

Key: If one physician performs the staged lesion excision(s), and a separate pathologist performs the histopathology and/or frozen section margin exam(s), the Mohs codes are not appropriate. Instead, the physician should bill the excision using a surgical code such as 11102 (Tangential biopsy of skin (eg, shave, scoop, saucerize, curette); single lesion) and the pathologist should bill the pathology services using an appropriate code such as 88305 and 88331.

Documentation: If you’re billing the pathology services for these “false” Mohs cases that don’t warrant codes 17311-+17315, you need to ensure accurate documentation. That means clearly distinguishing specimens, stages, blocks, frozen sections, and permanent section exams to make sure you don’t leave money on the table, or open yourself to audit error risk.