CARC / RARC quick-reference

CARCs and RARCs are the standard codes that explain why a payer reduced or denied a line on an ERA. The platform shows them on every receivable line and denial detail; this page is the cheat-sheet for what the most common codes mean and which ones the platform can auto-correct.

How to read a denial code

Every adjustment carries:

Field	Example	Meaning
Group code	CO, PR, PI, OA	Who owes / why category.
CARC	CO-4, PR-1, CO-29	The reason.
RARC (optional)	M51, N522	A supplemental remark.
Amount	$45.00	Dollar impact.

Group codes:

Code	Meaning
CO	Contractual Obligation — provider write-off; cannot be billed to member.
PR	Patient Responsibility — bill the member (deductible, coinsurance, copay).
PI	Payer Initiated Reduction — same as CO from the provider's perspective.
OA	Other Adjustment — usually informational.

Common CARCs you will see

Contractual write-offs (CO)

Code	Meaning	Auto-correctable?
CO-1	Deductible amount	No — patient liability
CO-2	Coinsurance amount	No — patient liability
CO-3	Copay	No — patient liability
CO-4	Procedure code inconsistent with modifier	Yes — CO4ModifierHandler
CO-11	Diagnosis inconsistent with procedure	Manual
CO-16	Lacks information / submission errors	Yes — CO16MissingInfoHandler (auth attach, RARC hint)
CO-18	Duplicate claim/service	Yes — CO18DuplicateHandler
CO-22	Care may be covered by another payer	Manual — file on correct payer
CO-29	Past timely filing	Yes — CO29TimelyFilingHandler (with appeal/late-filing rules)
CO-45	Charge exceeds fee schedule	No — informational; the contracted rate is the truth
CO-50	Non-covered service	Manual review
CO-96	Non-covered charges	Manual
CO-97	Service included in another procedure	Yes — CO97BundleHandler
CO-109	Claim/service not covered by this payer	Manual
CO-119	Benefit maximum reached	Manual
CO-167	Diagnosis not covered	Manual
CO-197	Pre-cert/auth absent	Yes — CO16MissingInfoHandler (attach auth)

Patient responsibility (PR)

Code	Meaning
PR-1	Deductible (move to patient AR)
PR-2	Coinsurance
PR-3	Copay
PR-31	Patient cannot be identified as our insured
PR-49	Routine/preventive — non-covered
PR-204	Service not covered under patient's plan

PR-1, PR-2, PR-3 are auto-routed to the patient AR by the receivables posting flow.

Payer-initiated (PI) and other (OA)

Code	Meaning
PI-204	Not covered under benefit plan
OA-23	Impact of prior payer (informational, common on secondary claims)
OA-94	Processed in excess of charges
OA-100	Payment made by primary payer

Common RARCs

RARCs add detail. The handful you will see most often:

Code	Meaning
M51	Missing/incomplete/invalid procedure code
N4	Missing/incomplete/invalid prior treatment information
N30	Patient ineligible
N115	This decision was based on a Local Coverage Determination
N179	Additional information has been requested
N522	Duplicate of a claim processed
N640	Exceeds number/frequency approved

Where the platform auto-corrects

When a denial arrives, the auto-correction engine inspects the CARC and optionally the RARC; if a registered handler matches, an attempt is created and the claim is rebilled. Outcome is one of:

• SUCCESS — replacement claim built, submitted, paid.
• FAILED — handler ran but rebill was denied again.
• SKIPPED — handler decided this case is not safe to auto-fix.

Tracked on the Auto-correction tab of any denial, and aggregated on the Auto-correction success rate panel of the dashboard.

See also

• Status reference — denial and claim lifecycle states.
• Trigger or review auto-corrections — manually invoke or override a handler.
• Work the denials worklist — daily denial triage workflow.