Implement the X12 835 CARC and RARC remark code lookup and build an automated denial routing workflow that maps each code pair to the correct denial management queue and next action
Maintain a current reference of CARC codes from the CAQH CORE-published claim adjustment reason code list and RARC codes from the CMS-published remittance advice remark code list, refreshing the local database at least quarterly when CMS updates the RARC file
After parsing each CLP and CAS segment from the 835, build a denial record combining the CARC code, any associated RARC code from the RARC segment or MOA segment, the adjustment group code, and the adjustment amount for that claim line
Map each CARC code to a denial category such as eligibility, authorization, medical necessity, coding, timely filing, or duplicate using a maintained crosswalk table; the category determines which work queue receives the denial and which correction workflow is initiated
For denials mapped to coding errors, extract the procedure code from the original claim and the CARC description to determine whether the denial is for an invalid code, an incorrect modifier, a bundled service, or an incidental service, and route to the correct coding staff queue
For denials mapped to authorization errors, check whether an authorization exists in your authorization management system for the service; if an authorization exists but was not submitted with the claim, add the authorization number to the original claim and resubmit using claim frequency type 7 or 8 as appropriate
Track denial volume by CARC code and payer over rolling 30, 60, and 90 day windows to identify systemic billing errors that require upstream workflow correction rather than individual claim appeals
Known gotchas
CARC code 45 (charge exceeds fee schedule) is a contractual adjustment and should be written off, not appealed; routing CARC 45 adjustments to an appeals queue wastes staff time and inflates the appeal workload metric without producing additional revenue
Some payers use a generic CARC code such as CARC 96 (non-covered charge) when the actual denial reason is a more specific code like lack of prior authorization; the RARC code accompanying CARC 96 often contains the true denial reason, and routing on CARC alone without inspecting the RARC produces incorrect queue assignments
RARC codes prefixed with M are Medicare-specific and are published by CMS separately from the standard RARC list; a routing table that only contains standard RARCs will not recognize M-prefixed codes, causing Medicare denial routing to fail silently
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One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp