Denial reason codes (CARC & RARC), explained
The codes on your EOB and denial letter are standardized — but cryptic. Look up what each CARC (Claim Adjustment Reason Code) and RARC (Remittance Advice Remark Code) actually means, whether it’s usually worth appealing, and what to do next.
All 32 codes verified active against the live X12 list (June 2026); none retired. New to EOBs? Start with what an EOB is.
Often appealable — commonly worth a patient appeal. Depends — pin down the exact reason first. Usually not — normal cost-share or a provider/contractual matter. “Appealable” doesn’t mean you’ll win — it means it’s often worth challenging.
Jump to a category:
Medical necessity
The plan questioned whether the care was needed. Among the most appealable denials.
CARC 50 — Not medically necessary
Often appealableWhat it means: The plan decided the service wasn't medically necessary.
What it means for you: One of the most appealable denials — a letter from your doctor plus clinical guidelines often overturns it.
CARC 151 — Too many services for the records
Often appealableWhat it means: The plan says the records don't support this many services.
What it means for you: Records showing why the care was needed at that frequency can support an appeal.
RARC N115 — Local coverage policy
Often appealableWhat it means: The denial relied on a specific local coverage policy.
What it means for you: Review that policy's criteria and show your case meets them.
Denied as not medically necessary? Build your appeal free.
Prior authorization
The plan says required approval wasn’t on file before the service.
CARC 197 — No prior authorization on file
Often appealableWhat it means: Required prior authorization wasn't on file.
What it means for you: If it was obtained, or wasn't actually required (e.g., an emergency), that's a strong appeal.
Auth was obtained or not required? Build your appeal free.
“Not covered”
“Not covered” has many causes — the exact reason determines the appeal.
CARC 96 — Not covered (reason unspecified)
Depends — pin down the exact reasonWhat it means: The plan is treating the charge as not covered.
What it means for you: “Not covered” has many causes (exclusion, coding, medical necessity, prior auth) — pin down the exact reason; it determines the appeal.
CARC 204 — Not a covered benefit
Depends — pin down the exact reasonWhat it means: The item isn't a covered benefit under the current plan.
What it means for you: Check the plan documents; if it should be covered (or a formulary/exception applies), it can be appealed.
CARC 167 — Diagnosis not covered
Depends — pin down the exact reasonWhat it means: The diagnosis billed isn't covered for this service.
What it means for you: Often a coding issue, or appealable with the correct diagnosis/records.
RARC N130 — See plan coverage rules
Depends — pin down the exact reasonWhat it means: Points you to the plan's coverage rules for this service.
What it means for you: Check those documents to see exactly what restriction was applied.
RARC N448 — Not on covered/fee list
Depends — pin down the exact reasonWhat it means: The item isn't on the plan's covered/fee list.
What it means for you: Check for a coverage exception or formulary process you can request.
Not sure why it’s “not covered”? Start free and we’ll help find the angle.
Coding / billing errors
Often a provider coding fix — frequently not something you owe.
CARC 4 — Modifier / procedure mismatch
Depends — pin down the exact reasonWhat it means: A modifier/procedure-code mismatch on the provider's claim.
What it means for you: Usually fixed by the provider correcting and resubmitting — not something you owe.
CARC 11 — Diagnosis–procedure mismatch
Depends — pin down the exact reasonWhat it means: The diagnosis and procedure codes didn't line up for the plan.
What it means for you: Often a coding fix; can be appealed with corrected coding or records.
CARC 18 — Duplicate claim
Depends — pin down the exact reasonWhat it means: The plan flagged this as billed twice.
What it means for you: If truly a duplicate you shouldn't owe it twice; if not, ask them to reprocess.
CARC 97 — Bundled into another service
Depends — pin down the exact reasonWhat it means: The plan treated this as bundled into another paid service.
What it means for you: If it was a separate, distinct service, it can be appealed with documentation.
RARC M51 — Procedure-code problem
Depends — pin down the exact reasonWhat it means: A procedure-code problem on the claim.
What it means for you: Typically a provider coding correction.
RARC M76 — Diagnosis-code problem
Depends — pin down the exact reasonWhat it means: A diagnosis-code problem on the claim.
What it means for you: Typically a provider coding correction.
Think it’s a coding error? Get a free diagnosis of your denial.
More information / documents needed
Often resolved by sending exactly what the plan asked for.
CARC 16 — Missing info / billing error
Depends — pin down the exact reasonWhat it means: The claim is missing information or has a billing error.
What it means for you: Ask exactly what's needed — often fixable by sending the missing information.
CARC 252 — Supporting documents needed
Depends — pin down the exact reasonWhat it means: The plan needs supporting documents before it can decide.
What it means for you: Usually resolved by sending the requested records.
RARC M127 — Medical record requested
Depends — pin down the exact reasonWhat it means: The plan wants the medical record for this service.
What it means for you: Sending the records often resolves it.
RARC MA130 — Can’t process as submitted
Usually not a denial you appealWhat it means: The claim couldn't be processed as submitted (missing/invalid info).
What it means for you: Usually corrected and resubmitted rather than appealed.
Need to respond with records? Start free.
Wrong payer / coordination of benefits
Usually a question of which plan pays first — a fix, not a true denial.
CARC 22 — Coordination of benefits
Depends — pin down the exact reasonWhat it means: Another insurer may need to pay first (coordination of benefits).
What it means for you: Confirm which plan is primary; usually a coordination fix, not a true denial.
CARC 109 — Sent to the wrong plan
Depends — pin down the exact reasonWhat it means: Sent to the wrong plan — another payer should handle it.
What it means for you: Usually resolved by submitting to the correct payer.
Sorted out which plan is primary and still denied? Start free.
Eligibility
If you were actually covered/eligible, dispute it with proof.
CARC 27 — Coverage had ended
Depends — pin down the exact reasonWhat it means: The plan says coverage had ended on the service date.
What it means for you: If you were actually covered, dispute it with proof of active coverage.
RARC N30 — Not eligible for this service
Depends — pin down the exact reasonWhat it means: The plan says you weren't eligible for this service.
What it means for you: If you were, dispute it with proof of eligibility.
CARC B7 — Provider not certified for this service
Depends — pin down the exact reasonWhat it means: The provider wasn't certified/eligible to be paid for this specific service on this date.
What it means for you: A provider-side certification/enrollment issue — usually the provider resolves it with the plan; typically not something you owe.
Were you actually covered? Build your appeal free.
Timely filing & contractual
Often the provider’s responsibility — not a bill you should owe.
CARC 29 — Filed too late
Depends — pin down the exact reasonWhat it means: The claim was filed after the plan's time limit.
What it means for you: Almost always the provider's responsibility — you generally shouldn't be billed for a provider's late filing.
CARC 45 — Above allowed/contracted rate
Usually not a denial you appealWhat it means: The charge is above the plan's allowed/contracted rate.
What it means for you: A contractual write-off between provider and plan — typically NOT your responsibility if the provider is in-network.
Being billed for a provider’s issue? Check it free.
Benefit limits / frequency
Check whether the limit was applied correctly and whether an exception applies.
CARC 119 — Benefit limit reached
Depends — pin down the exact reasonWhat it means: A plan limit (visits or dollars) for this benefit was reached.
What it means for you: Check whether the limit was applied correctly and whether an exception applies.
RARC N362 — Days/units over the plan limit
Often appealableWhat it means: The number of days/units billed exceeds the plan's acceptable maximum.
What it means for you: Records showing the extra days/units were medically needed can support an appeal.
Hit a limit you think was wrong? Build your appeal free.
Appeal rights notice
Not a denial — it’s your notice of how and by when to appeal.
RARC MA01 — Your appeal rights & deadline
Often appealableWhat it means: Notice of your right to appeal and the deadline to do it.
What it means for you: Read it for the time limit and where to send your appeal.
Got your appeal-rights notice? Get a free diagnosis before the deadline.
Frequently asked questions
What’s the difference between a CARC and a RARC code?
A CARC (Claim Adjustment Reason Code) explains why an amount was adjusted or denied. A RARC (Remittance Advice Remark Code) adds extra detail on top of a CARC. Both appear on your EOB and remittance.
Where do I find my denial code?
On your Explanation of Benefits (EOB) or denial letter, usually next to the denied line with a short reason and a key explaining each code.
Does a denial code mean I have to pay?
Not necessarily. Some codes are normal cost-sharing, some are provider or coding issues you don’t owe, and many denials can be appealed. The code tells you which situation you’re in.
Are these codes the same for every insurer?
Yes — CARC and RARC are national X12 standards used across payers. Insurers layer their own internal policies on top, so the exact reason can still vary.
How current is this list?
It was verified against official X12 and CMS sources in June 2026. X12 updates codes a few times a year, so always confirm against your own denial letter.
This is general information to help you understand your denial — not legal, medical, billing, or coverage advice, and not a guarantee of any outcome. Always confirm specifics against your own denial letter and plan documents.
IntelClaim is a self-help tool — not legal, medical, or insurance advice — and does not guarantee any particular outcome. Information on this site is general and may not reflect the rules of your specific plan or state. Always read your own denial letter, plan documents, and the deadlines that apply to you, and consider professional advice for your situation. No PHI is collected on this marketing site.