A printable cheat sheet for CARC and RARC denial codes, what they mean, why they happen, and how to fix them. Preview 10 codes below, or download the full 40-code PDF with appeal language.
These 10 codes account for roughly 60% of commercial and Medicare denials. The full cheat sheet covers 40 codes plus line-by-line appeal language.
| Code | Meaning | Common Cause | Quick Fix |
|---|---|---|---|
| CO-16 | Claim lacks information needed for adjudication | Missing modifier, NPI, or required data element | Review RARC remark, correct missing field, resubmit |
| CO-22 | Care may be covered by another payer (COB) | Coordination of benefits not updated | Obtain primary EOB, update COB, rebill with attachment |
| CO-29 | Time limit for filing has expired | Claim submitted past payer filing deadline | Submit proof of timely filing via clearinghouse receipt |
| CO-45 | Charge exceeds fee schedule / contracted amount | Informational write-off to contractual allowance | No appeal needed unless contract rate is wrong, verify fee schedule |
| CO-50 | Non-covered services, not deemed medically necessary | Diagnosis-to-procedure mismatch or LCD exclusion | Add supporting diagnosis, attach medical records, cite LCD |
| CO-97 | Service is included / bundled into another service | NCCI edit or global surgical package bundling | Review NCCI edits, apply modifier 59/XE/XP/XS/XU if clinically justified |
| CO-109 | Claim not covered by this payer | Wrong payer billed or enrollment not active | Verify eligibility, route to correct payer, check enrollment |
| PR-1 | Deductible amount | Patient has not met annual deductible | Bill patient; no appeal required |
| PR-3 | Co-payment amount | Plan-specified visit co-pay | Collect from patient at time of service or via statement |
| PR-27 | Expenses incurred after coverage terminated | Eligibility lapsed on DOS | Verify eligibility, bill patient or appeal with retroactive reinstatement |
You'll receive the PDF within 5 minutes. Printable, one-page-per-five-codes format, perfect for a billing desk.
Every ERA/835 denial has two code types working together. CARC (Claim Adjustment Reason Codes) tell you WHY a claim was adjusted or denied, they're standardized across all payers. RARC (Remittance Advice Remark Codes) provide supplementary detail, the "which field is missing" or "why this NCCI edit fired" context that makes the CARC actionable.
A denial with CARC CO-16 alone is unactionable. The paired RARC (for example, MA27, "Missing/incomplete/invalid entitlement number or name shown on the claim") tells you exactly what needs to be fixed. The full cheat sheet includes the top 25 RARC pairings for the most common CARC denials.
The two-letter prefix on every CARC identifies who is financially responsible: CO (Contractual Obligation, write-off), PR (Patient Responsibility, bill the patient), OA (Other Adjustment), PI (Payer Initiated Reduction), CR (Correction and Reversal). Misreading the group code leads to billing patients for amounts they don't owe, which creates compliance risk and patient complaints.
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