Medicare Administrative Contractor Expands Coverage of Special Histochemical, Immunohistochemical Stains

A revised local coverage determination, effective June 7, 2025, expands coverage for special histochemical stains and immunohistochemical (IHC) stains.

Cigna Government Services, the Medicare Administrative Contractor for Ohio and Kentucky, is expanding its coverage to include special histochemical and IHC stains across subspecialties such as breast, lung, and prostate pathology.

The services must be “medically necessary” for “a complete and accurate diagnosis” to be reported to the treating clinician, and the results of the test should be communicated to and used by the treating clinician for the beneficiary. The pathologist must also document why additional testing was performed.

The following scenarios are considered overutilization or incorrect billing of these services:

• Reflex templates or preorders for special stains and/or IHC stains prior to review of the routine hematoxylin and eosin stain by the pathologist
• Use of special stains and/or IHC stains without clinical evidence that the stain is actionable or provides the treating physician with information that changes patient management
• Use of added stains when the diagnosis is already known based on morphologic evaluation of the primary stain

Billing and coding guidelines are available on the Centers for Medicare and Medicaid website.

Sources:

https://www.cms.gov/medicare-coverage-database/view/lcd.aspx?lcdId=35986&ver=35