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- Newest: contracted funding agreement, payer and provider, start November 1, 2025 [2]
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The Work Genie Brief · Issue 1, November 2026
The October 1 code update: which worklist rules it breaks, and the November cycle to watch
Short answer: CR 14492 loaded the July 1, 2026 X12 lists for dates of service from October 1; eighteen new remark codes, five that change where a denial goes; four deactivated CARCs still in old routing rules; and the 30-minute diff to run before the November list.
CR 14492 · Transmittal 13791
N923 to N940 · start Jul 1, 2026
CARC 15, 138, 165, 168 · stopped 2018
Next X12 list · about Nov 1
Edition
Issue 1 · Nov 2026
Focus
CARC and RARC update
Codes
N923 to N940
Framework
CR 14492 · TR 13791
Effective date
Oct 1, 2026
Length
5 min read
CR 14492 and the October 1 effective date
Transmittal 13791 loads the July 1 X12 lists [1]: new codes on their start dates, modifications on their effective dates, deactivated codes dropped, with two carve-outs that let a dead code land in your 835.
- 1May 27, 2026CR 14492 issued [1]
- 2Jul 1, 2026X12 lists the CR loads [1]
- 3Oct 1, 2026Effective by date of service [1]
- 4Oct 5, 2026Contractor implementation [1]
- 5About Nov 1Next X12 list
Carve-out 1
COB claims adjudicated by the primary before deactivation
Carve-out 2
Reversals and corrections forwarded before it
Deactivated codes may still appear
Eighteen new remark codes, five that move the line
N923 to N940 by type [3]
Zero CARCs carry a 2026 start date [2].
Dental and imaging attachmentsN927 to N934, N940
950% of the 18
Change where a denied line goesN935 to N939
528%
MA encounter-data responsesN923 to N926
422%
CARCs with a 2026 start date
00%
0369 codes
Attachment and encounter remarksChange routingCARC side, unchanged
Where the line goes now, code by code
| Code [3] | Says | Where the line goes now |
|---|---|---|
| N938 | Do not resubmit; claim will be reprocessed | Hold 30 days, check the reprocessed 835; not rework |
| N939 | Peer-to-peer review available | Clinical owner, peer-to-peer before written appeal |
| N937 | Service line denial threshold exceeded | Payer escalation task; a pattern, not a line |
| N936 | Secondary or tertiary procedure under the Medicare MPPR | Contract variance check, then close |
| N935 | Patient no longer Medicaid or QMB | Eligibility; re-verify before any statement |
| N921 March list | Reconsideration or appeal time limit expired | Write-off review, reason captured; not the appeal queue |
| N920 March list | Payment on hold during contract renegotiation | Whoever owns the contract |
The deactivated codes still in your rules
CARCs 15 (authorization), 138 (appeal procedures), 165 (referral) and 168 (dental plan benefit) stopped May 1, 2018 [2]; rules keyed to them, written from payer manuals, still turn up on books we take over.
- 1RuleCARC 15 routes to the auth team
- 22018Code deactivated [2]
- 3TodayPayer sends 197
- 4ResultLine falls to the generic queue
The remedy
A diff, not a rewrite: validate every rule against the X12 dates
Work Genie: 297 CARCs, 1,137 RARCs with dates; rules validated per load
Full code-to-owner map: denial worklist white paper.
New: the denial worklist white paper, the clean claim rate guide, our read of the payer prior-auth metrics, and the AR Workflow Engine page.
Takeaway
Export the distinct code combinations from your last 60 days of 835s; diff them against the July 1 X12 lists and your routing rules. Stop-dated codes and new codes with no rule are your list.
Three steps this week
Pull the distinct combinations with denied dollarsMost practice management systems export this in one report.
Mark the gapsCombinations with no routing rule; rules keyed to a stop-dated code.
Write the routing rows from Story 2 into the worklistCalendar the diff for the week after November 1; the free denial audit runs it on your last 90 days.
Frequently asked questions
What did CMS CR 14492 change?
It instructs Medicare contractors to load the CARC and RARC lists X12 published on July 1, 2026, effective for dates of service on or after October 1, 2026, implemented October 5, 2026, and to stop reporting deactivated codes except on certain coordination-of-benefits and reversal claims adjudicated before the deactivation.
Which new remark codes affect denial routing?
N938 (do not resubmit, the claim will be reprocessed), N939 (peer-to-peer review available), N937 (service line denial threshold exceeded) and, from the March 2026 list, N921 (reconsideration or appeal time limit expired). Each sends the line to a different owner than a generic denial rule would.
How often should we re-check our worklist rules?
Three times a year, in the week after X12 publishes around March 1, July 1 and November 1. Diff the distinct CARC and RARC pairs in your last 60 days of 835s against the new list and against your routing rules, and retire any rule keyed to a code with a stop date.
- CMS Transmittal 13791, Change Request 14492: Claims Adjustment Reason Code (CARC), Remittance Advice Remark Code (RARC), MREP and PC Print Update (issued May 27, 2026; effective October 1, 2026; implementation October 5, 2026)
- X12, Claim Adjustment Reason Codes (official code list, with start, modified and stop dates)
- X12, Remittance Advice Remark Codes (official code list, with start, modified and stop dates)
Checked October 25, 2026. Rules change; confirm against the source before relying on them.
Want the diff run on your remittances?
Send 90 days of 835s and we return the distinct code pairs, the rules they break and the denied dollars sitting behind each.