Instantly find explanations, causes, and resolution steps for every Claim Adjustment Reason Code (CARC) and Remark Code.
Claim Adjustment Reason Codes (CARC) explain why a payment differs from what was billed. Every 835 ERA and EOB uses these standardized codes.
Search any code or keyword above. Each page includes the full description, common causes, resolution steps, and appeal guidance.
Each denial code page also links to a dedicated Remark Code page — optimized for providers searching for ERA remark code context.
Most denials are reversible. Our guides walk you through the correct steps to correct, resubmit, or formally appeal each denial type.
| Code | Description | View |
|---|---|---|
| MA56 | Our records show you have opted out of Medicare, agreeing with the patient not to bil… | Details → |
| MA56 | Our records show you have opted out of Medicare, agreeing with the patient not to bil… | Details → |
| MA57 | Patient submitted written request to revoke his/her election for religious non-medica… | Details → |
| MA57 | Patient submitted written request to revoke his/her election for religious non-medica… | Details → |
| MA58 | Missing/incomplete/invalid release of information indicator. | Details → |
| MA58 | Missing/incomplete/invalid release of information indicator. | Details → |
| MA59 | Alert: The patient overpaid you for these services. You must issue the patient a refu… | Details → |
| MA59 | Alert: The patient overpaid you for these services. You must issue the patient a refu… | Details → |
| MA60 | Missing/incomplete/invalid patient relationship to insured. | Details → |
| MA60 | Missing/incomplete/invalid patient relationship to insured. | Details → |
| MA61 | Missing/incomplete/invalid social security number. | Details → |
| MA61 | Missing/incomplete/invalid social security number. | Details → |
| MA62 | Alert: This is a telephone review decision. | Details → |
| MA62 | Alert: This is a telephone review decision. | Details → |
| MA63 | Missing/incomplete/invalid principal diagnosis. | Details → |
| MA63 | Missing/incomplete/invalid principal diagnosis. | Details → |
| MA64 | Our records indicate that we should be the third payer for this claim. We cannot proc… | Details → |
| MA64 | Our records indicate that we should be the third payer for this claim. We cannot proc… | Details → |
| MA65 | Missing/incomplete/invalid admitting diagnosis. | Details → |
| MA65 | Missing/incomplete/invalid admitting diagnosis. | Details → |
| MA66 | Missing/incomplete/invalid principal procedure code. | Details → |
| MA66 | Missing/incomplete/invalid principal procedure code. | Details → |
| MA67 | Alert: Correction to a prior claim. | Details → |
| MA67 | Alert: Correction to a prior claim. | Details → |
| MA68 | Alert: We did not crossover this claim because the secondary insurance information on… | Details → |
| MA68 | Alert: We did not crossover this claim because the secondary insurance information on… | Details → |
| MA69 | Missing/incomplete/invalid remarks. | Details → |
| MA69 | Missing/incomplete/invalid remarks. | Details → |
| MA70 | Missing/incomplete/invalid provider representative signature. | Details → |
| MA70 | Missing/incomplete/invalid provider representative signature. | Details → |
| MA71 | Missing/incomplete/invalid provider representative signature date. | Details → |
| MA71 | Missing/incomplete/invalid provider representative signature date. | Details → |
| MA72 | Alert: The patient overpaid you for these assigned services. You must issue the patie… | Details → |
| MA72 | Alert: The patient overpaid you for these assigned services. You must issue the patie… | Details → |
| MA73 | Informational remittance associated with a Medicare demonstration. No payment issued … | Details → |
| MA73 | Informational remittance associated with a Medicare demonstration. No payment issued … | Details → |
| MA74 | Alert: This payment replaces an earlier payment for this claim that was either lost, … | Details → |
| MA74 | Alert: This payment replaces an earlier payment for this claim that was either lost, … | Details → |
| MA75 | Missing/incomplete/invalid patient or authorized representative signature. | Details → |
| MA75 | Missing/incomplete/invalid patient or authorized representative signature. | Details → |
| MA76 | Missing/incomplete/invalid provider identifier for home health agency or hospice when… | Details → |
| MA76 | Missing/incomplete/invalid provider identifier for home health agency or hospice when… | Details → |
| MA77 | Alert: The patient overpaid you. You must issue the patient a refund within 30 days f… | Details → |
| MA77 | Alert: The patient overpaid you. You must issue the patient a refund within 30 days f… | Details → |
| MA78 | The patient overpaid you. You must issue the patient a refund within 30 days for the … | Details → |
| MA78 | The patient overpaid you. You must issue the patient a refund within 30 days for the … | Details → |
| MA79 | Billed in excess of interim rate. | Details → |
| MA79 | Billed in excess of interim rate. | Details → |
| MA80 | Informational notice. No payment issued for this claim with this notice. Payment issu… | Details → |
| MA80 | Informational notice. No payment issued for this claim with this notice. Payment issu… | Details → |
| MA81 | Missing/incomplete/invalid provider/supplier signature. | Details → |
| MA81 | Missing/incomplete/invalid provider/supplier signature. | Details → |
| MA82 | Missing/incomplete/invalid provider/supplier billing number/identifier or billing nam… | Details → |
| MA82 | Missing/incomplete/invalid provider/supplier billing number/identifier or billing nam… | Details → |
| MA83 | Did not indicate whether we are the primary or secondary payer. | Details → |
| MA83 | Claim/service lacks information or has submission/billing error(s). Did not indicate… | Details → |
| MA83 | Did not indicate whether we are the primary or secondary payer. | Details → |
| MA84 | Patient identified as participating in the National Emphysema Treatment Trial but our… | Details → |
| MA84 | Patient identified as participating in the National Emphysema Treatment Trial but our… | Details → |
| MA85 | Our records indicate that a primary payer exists (other than ourselves); however, you… | Details → |
Medical claim denial codes — formally known as Claim Adjustment Reason Codes (CARC) — are standardized identifiers maintained by the X12 standards body and used across all Medicare, Medicaid, and commercial payer 835 electronic remittance transactions. When a claim is paid at a different amount than billed, at least one CARC code must accompany the remittance advice to indicate the specific reason for the adjustment.
The most frequently encountered codes include CO-16 (missing or invalid claim information), CO-45 (charges exceeding fee schedule), PR-1 (patient deductible), CO-29 (timely filing deadline exceeded), and CO-4 (procedure code inconsistent with modifier). Each represents a distinct, actionable reason that has a defined resolution pathway.