Knowledge Base Article

One of the frustrations of dealing with the overwhelming volume of reviews by Medicare contractors is often the lack of guidance from Medicare on how to handle a particular issue. In June, CMS released several MLN Matters SE articles concerning some of the findings of CERT and Recovery Auditors. These articles describe the issue and the corrective actions necessary for providers to resolve the issue. Although some of these are obvious resolutions – such as, only one cataract removal per eye – I wanted to point out the information on Mohs surgery and also make you aware of some of the other issues that are addressed.

The correct billing of Mohs Micrographic Surgical (MMS) services affects both hospitals and physicians and recent Recovery Auditor reviews have revealed errors in the billing of MMS. Medicare will only reimburse for MMS services when the Mohs surgeon acts as both surgeon and pathologist. Providers should not bill Medicare for these procedures if preparation or interpretation of pathology slides is performed by a physician other than the Mohs surgeon.

Mohs surgery is a two-step process where the tumor is removed in stages with histologic evaluation after each stage until all margins are clear. The performing physician serves as both surgeon and pathologist, performing both the excision and histologic evaluation of the specimen. The CPT codes for MMS (CPTs 17311-17315) should not be billed with separate CPT codes for the histologic evaluation of the tumor tissue removed. If the histology is performed by another physician, the excision should be billed with the standard malignant tissue excision codes (CPT 11600-11646) and the histologic evaluation with the surgical pathology code (CPT 88305).

Other Medicare requirements for coverage of Mohs surgery include:

• The surgery must be of a higher degree of complexity that most skin cancers, such as poorly defined borders, possible deep invasion, prior irradiation or when maximum conservation of tumor-free tissue is important.
• Only physicians (MDs or DOs) specifically trained and highly skilled in MMS techniques and pathological identification may perform Mohs surgery.
• Medical record documentation should support the medical necessity of the procedure including the location, number and size of the lesions; the number of stages; the number of specimens per stage; and a detailed description of the histology of the specimens.

For complete information, please read MLN Matters Article SE1318.

Issues addressed by other MLN Matters SE articles include:

• Appending modifiers to duplicate services billed for the same patient on the same date – SE1314.
• Billing the correct drug units by converting dosage of drugs given (such as milligrams) to units based on HCPCS description – SE1316.
• Billing cataract removal only once per eye – SE1319.
• Being sure to include the code for the primary service when billing add-on codes – SE1320.
• Appropriate bundling of outpatient services onto the inpatient claim under the 3-day window billing rule – SE3124.