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 |
|---|---|---|
| N609 | 80% of the provider's billed amount is being recommended for payment according to Act… | Details → |
| N61 | Rebill services on separate claims. | Details → |
| N61 | Rebill services on separate claims. | Details → |
| N610 | Alert: Payment based on an appropriate level of care. | Details → |
| N610 | Alert: Payment based on an appropriate level of care. | Details → |
| N611 | Claim in litigation. Contact insurer for more information. | Details → |
| N611 | Claim in litigation. Contact insurer for more information. | Details → |
| N612 | Medical provider not authorized/certified to provide treatment to injured workers in … | Details → |
| N612 | Medical provider not authorized/certified to provide treatment to injured workers in … | Details → |
| N613 | Alert: Although this was paid, you have billed with an ordering provider that needs t… | Details → |
| N613 | Alert: Although this was paid, you have billed with an ordering provider that needs t… | Details → |
| N614 | Alert: Additional information is included in the 835 Healthcare Policy Identification… | Details → |
| N614 | Alert: Additional information is included in the 835 Healthcare Policy Identification… | Details → |
| N615 | Alert: This enrollee receiving advance payments of the premium tax credit is in the g… | Details → |
| N615 | Alert: This enrollee receiving advance payments of the premium tax credit is in the g… | Details → |
| N616 | Alert: This enrollee is in the first month of the advance premium tax credit grace pe… | Details → |
| N616 | Alert: This enrollee is in the first month of the advance premium tax credit grace pe… | Details → |
| N617 | This enrollee is in the second or third month of the advance premium tax credit grace… | Details → |
| N617 | This enrollee is in the second or third month of the advance premium tax credit grace… | Details → |
| N618 | Alert: This claim will automatically be reprocessed if the enrollee pays their premiu… | Details → |
| N618 | Alert: This claim will automatically be reprocessed if the enrollee pays their premiu… | Details → |
| N619 | Coverage terminated for non-payment of premium. | Details → |
| N619 | Coverage terminated for non-payment of premium. | Details → |
| N62 | Dates of service span multiple rate periods. Resubmit separate claims. | Details → |
| N62 | Dates of service span multiple rate periods. Resubmit separate claims. | Details → |
| N620 | Alert: This procedure code is for quality reporting/informational purposes only. | Details → |
| N620 | Alert: This procedure code is for quality reporting/informational purposes only. | Details → |
| N621 | Charges for Jurisdiction required forms, reports, or chart notes are not payable. | Details → |
| N621 | Charges for Jurisdiction required forms, reports, or chart notes are not payable. | Details → |
| N622 | Not covered based on the date of injury/accident. | Details → |
| N622 | Not covered based on the date of injury/accident. | Details → |
| N623 | Not covered when deemed unscientific/unproven/outmoded/experimental/excessive/inappro… | Details → |
| N623 | Not covered when deemed unscientific/unproven/outmoded/experimental/excessive/inappro… | Details → |
| N624 | The associated Workers' Compensation claim has been withdrawn. | Details → |
| N624 | The associated Workers' Compensation claim has been withdrawn. | Details → |
| N625 | Missing/Incomplete/Invalid Workers' Compensation Claim Number. | Details → |
| N625 | Missing/Incomplete/Invalid Workers' Compensation Claim Number. | Details → |
| N626 | New or established patient E/M codes are not payable with chiropractic care codes. | Details → |
| N626 | New or established patient E/M codes are not payable with chiropractic care codes. | Details → |
| N627 | Service not payable per managed care contract. | Details → |
| N627 | Service not payable per managed care contract. | Details → |
| N628 | Out-patient follow up visits on the same date of service as a scheduled test or treat… | Details → |
| N628 | Out-patient follow up visits on the same date of service as a scheduled test or treat… | Details → |
| N629 | Reviews/documentation/notes/summaries/reports/charts not requested. | Details → |
| N629 | Reviews/documentation/notes/summaries/reports/charts not requested. | Details → |
| N63 | Rebill services on separate claim lines. | Details → |
| N63 | Rebill services on separate claim lines. | Details → |
| N630 | Referral not authorized by attending physician. | Details → |
| N630 | Referral not authorized by attending physician. | Details → |
| N631 | Medical Fee Schedule does not list this code. An allowance was made for a comparable … | Details → |
| N631 | Medical Fee Schedule does not list this code. An allowance was made for a comparable … | Details → |
| N632 | According to the Official Medical Fee Schedule this service has a relative value of z… | Details → |
| N632 | According to the Official Medical Fee Schedule this service has a relative value of z… | Details → |
| N633 | Additional anesthesia time units are not allowed. | Details → |
| N633 | Additional anesthesia time units are not allowed. | Details → |
| N634 | The allowance is calculated based on anesthesia time units. | Details → |
| N634 | The allowance is calculated based on anesthesia time units. | Details → |
| N635 | The Allowance is calculated based on the anesthesia base units plus time. | Details → |
| N635 | The Allowance is calculated based on the anesthesia base units plus time. | Details → |
| N636 | Adjusted because this is reimbursable only once per injury. | 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.