Pathology MIPS Measure 491

January 24, 2024

Last year, APS released multiple white papers on MIPS measure 491. We are issuing this update to those articles to provide more clarity around applicability of this measure and reporting requirements. When a pathology report is submitted which qualifies as a primary resection or biopsy for colorectal, gastroesophageal, endometrial, or small bowel carcinoma, Measure 491 requires documentation of an impression or recommendation for testing of mismatch repair (MMR) by immunohistochemistry (biomarkers MLH1, MSH2, MSH6, and PMS2), or microsatellite instability (MSI) by DNA-based testing status, or both.

Per CMS:
Diagnosis of primary colorectal, endometrial, gastroesophageal or small bowel carcinoma, biopsy or resection (ICD-10-CM®): C15.3, C15.4, C15.5, C15.8, C15.9, C16.0, C16.1, C16.2, C16.3, C16.4, C16.5, C16.6, C16.8, C16.9, C17.0, C17.1, C17.2, C17.3, C17.8, C17.9, C18.0, C18.2, C18.3, C18.4, C18.5, C18.6, C18.7, C18.8, C18.9, C19, C20, C26.0, C54.1, C54.3, C54.8, C54.9, C55

Excluded from this measure:
Patients with an existing diagnosis of squamous cell carcinoma of the esophagus

Appropriate documentation to support the requirements of this quality measure should be included on the original pathology report. Many cases do include the appropriate elements, but not until an amendment is made to the initial report. APS submits data on a regular basis to our registries, rather than a simple bulk upload annually to help with surveillance of each group’s performance in the MIPS program. Because of this ongoing transmittal to registries, it is imperative that the documentation on the original report contain a reference to the intended testing.

Anywhere on the original report, if MMR/MSI testing is likely to be or has already been performed, include a statement to indicate this.
“MMR/MSI testing will be performed as indicated for specimen A”
“MMR/MSI testing to follow in an amendment”
“MMR/MSI testing not recommended due to ___”
“MMR/MSI testing performed on previous specimen and not repeated.”

MMR/MSI can be replaced with any of the following terms:
Mismatch repair, microsatellite instability

It is not necessary to include results if the testing is still outstanding. Statements such as the above indicating the impression of, or recommendation for testing, qualify the case as “met” per CMS guidance.

Detailed measure specifics are available from CMS. 


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