A significant mismatch rate should trigger structured CDI/coding reconciliation, not an assumption that either department is wrong.
Working MS-DRGs are provisional. Final coding may change because of discharge-summary diagnoses, operative reports, pathology results, late physician clarification, Coding Clinic guidance, sequencing conventions, final procedure coding, CC/MCC exclusions, or other grouper logic unavailable during the concurrent CDI review.
The manager should categorize mismatch causes. Useful categories include principal-diagnosis differences, missed secondary diagnoses, procedure-code differences, coding-guideline interpretation, query results, discharge documentation, and technical grouper issues.
Patterns can then identify whether education is needed for CDI specialists, coding professionals, physicians, or multiple groups.
Requiring coding staff to adopt the CDI working DRG would undermine coding independence and final coding accountability. Excluding mismatches from metrics would conceal an important quality indicator.
CMS confirms that the FY 2026 MS-DRG Definitions Manual contains the complete grouper logic for Version 43.1, making current grouper rules essential when evaluating discrepancies.
CCDS Reference Topics: MS-DRG reconciliation; CDI/coder agreement; program analysis; education; grouper logic.
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