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 |
|---|---|---|
| N743 | Adjusted because the services may be related to an employment accident. | Details → |
| N744 | Adjusted because the services may be related to an auto/other accident. | Details → |
| N744 | Adjusted because the services may be related to an auto/other accident. | Details → |
| N745 | Missing Ambulance Report. | Details → |
| N745 | Missing Ambulance Report. | Details → |
| N746 | Incomplete/invalid Ambulance Report. | Details → |
| N746 | Incomplete/invalid Ambulance Report. | Details → |
| N747 | This is a misdirected claim/service. Submit the claim to the payer/plan where the pat… | Details → |
| N747 | This is a misdirected claim/service. Submit the claim to the payer/plan where the pat… | Details → |
| N748 | Adjusted because the related hospital charges have not been received. | Details → |
| N748 | Adjusted because the related hospital charges have not been received. | Details → |
| N749 | Missing Blood Gas Report. | Details → |
| N749 | Missing Blood Gas Report. | Details → |
| N75 | Missing/incomplete/invalid tooth surface information. | Details → |
| N75 | Missing/incomplete/invalid tooth surface information. | Details → |
| N750 | Incomplete/invalid Blood Gas Report. | Details → |
| N750 | Incomplete/invalid Blood Gas Report. | Details → |
| N751 | Adjusted because the patient is covered under a Medicare Part D plan. | Details → |
| N751 | Adjusted because the patient is covered under a Medicare Part D plan. | Details → |
| N752 | Missing/incomplete/invalid HIPPS Treatment Authorization Code (TAC). | Details → |
| N752 | Missing/incomplete/invalid HIPPS Treatment Authorization Code (TAC). | Details → |
| N753 | Missing/incomplete/invalid Attachment Control Number. | Details → |
| N753 | Missing/incomplete/invalid Attachment Control Number. | Details → |
| N754 | Missing/incomplete/invalid Referring Provider or Other Source Qualifier on the 1500 C… | Details → |
| N754 | Missing/incomplete/invalid Referring Provider or Other Source Qualifier on the 1500 C… | Details → |
| N755 | Missing/incomplete/invalid ICD Indicator. | Details → |
| N755 | Missing/incomplete/invalid ICD Indicator. | Details → |
| N756 | Missing/incomplete/invalid point of drop-off address. | Details → |
| N756 | Missing/incomplete/invalid point of drop-off address. | Details → |
| N757 | Adjusted based on the Federal Indian Fees schedule (MLR). | Details → |
| N757 | Adjusted based on the Federal Indian Fees schedule (MLR). | Details → |
| N758 | Adjusted based on the prior authorization decision. | Details → |
| N758 | Adjusted based on the prior authorization decision. | Details → |
| N759 | Payment adjusted based on the National Electrical Manufacturers Association (NEMA) St… | Details → |
| N759 | Payment adjusted based on the National Electrical Manufacturers Association (NEMA) St… | Details → |
| N76 | Missing/incomplete/invalid number of riders. | Details → |
| N76 | Missing/incomplete/invalid number of riders. | Details → |
| N760 | This facility is not authorized to receive payment for the service(s). | Details → |
| N760 | This facility is not authorized to receive payment for the service(s). | Details → |
| N761 | This provider is not authorized to receive payment for the service(s). | Details → |
| N761 | This provider is not authorized to receive payment for the service(s). | Details → |
| N762 | This facility is not certified for Tomosynthesis (3-D) mammography. | Details → |
| N762 | This facility is not certified for Tomosynthesis (3-D) mammography. | Details → |
| N763 | The demonstration code is not appropriate for this claim; resubmit without a demonstr… | Details → |
| N763 | The demonstration code is not appropriate for this claim; resubmit without a demonstr… | Details → |
| N764 | Missing/incomplete/invalid Hematocrit (HCT) value. | Details → |
| N764 | Missing/incomplete/invalid Hematocrit (HCT) value. | Details → |
| N765 | This payer does not cover coinsurance assessed by a previous payer. | Details → |
| N765 | This payer does not cover coinsurance assessed by a previous payer. | Details → |
| N766 | This payer does not cover co-payment assessed by a previous payer. | Details → |
| N766 | This payer does not cover co-payment assessed by a previous payer. | Details → |
| N767 | The Medicaid state requires provider to be enrolled in the member's Medicaid state pr… | Details → |
| N767 | The Medicaid state requires provider to be enrolled in the member's Medicaid state pr… | Details → |
| N768 | Incomplete/invalid initial evaluation report. | Details → |
| N768 | Incomplete/invalid initial evaluation report. | Details → |
| N769 | A lateral diagnosis is required. | Details → |
| N769 | A lateral diagnosis is required. | Details → |
| N77 | Missing/incomplete/invalid designated provider number. | Details → |
| N77 | Missing/incomplete/invalid designated provider number. | Details → |
| N770 | The adjustment request received from the provider has been processed. Your original c… | 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.