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 |
|---|---|---|
| N530 | Not Qualified for Recovery based on enrollment information. | Details → |
| N531 | Not qualified for recovery based on direct payment of premium. | Details → |
| N531 | Not qualified for recovery based on direct payment of premium. | Details → |
| N532 | Not qualified for recovery based on disability and working status. | Details → |
| N532 | Not qualified for recovery based on disability and working status. | Details → |
| N533 | Services performed in an Indian Health Services facility under a self-insured tribal … | Details → |
| N533 | Services performed in an Indian Health Services facility under a self-insured tribal … | Details → |
| N534 | This is an individual policy, the employer does not participate in plan sponsorship. | Details → |
| N534 | This is an individual policy, the employer does not participate in plan sponsorship. | Details → |
| N535 | Payment is adjusted when procedure is performed in this place of service based on the… | Details → |
| N535 | Payment is adjusted when procedure is performed in this place of service based on the… | Details → |
| N536 | We are not changing the prior payer's determination of patient responsibility, which … | Details → |
| N536 | We are not changing the prior payer's determination of patient responsibility, which … | Details → |
| N537 | We have examined claims history and no records of the services have been found. | Details → |
| N537 | We have examined claims history and no records of the services have been found. | Details → |
| N538 | A facility is responsible for payment to outside providers who furnish these services… | Details → |
| N538 | A facility is responsible for payment to outside providers who furnish these services… | Details → |
| N538 | Beneficiary was inpatient on date of service billed | Details → |
| N539 | Alert: We processed appeals/waiver requests on your behalf and that request has been … | Details → |
| N539 | Alert: We processed appeals/waiver requests on your behalf and that request has been … | Details → |
| N54 | Claim information is inconsistent with pre-certified/authorized services. | Details → |
| N54 | Claim information is inconsistent with pre-certified/authorized services. | Details → |
| N540 | Payment adjusted based on the interrupted stay policy. | Details → |
| N540 | Payment adjusted based on the interrupted stay policy. | Details → |
| N541 | Mismatch between the submitted insurance type code and the information stored in our … | Details → |
| N541 | Mismatch between the submitted insurance type code and the information stored in our … | Details → |
| N542 | Missing income verification. | Details → |
| N542 | Missing income verification. | Details → |
| N543 | Incomplete/invalid income verification. | Details → |
| N543 | Incomplete/invalid income verification. | Details → |
| N544 | Alert: Although this was paid, you have billed with a referring/ordering provider tha… | Details → |
| N544 | Alert: Although this was paid, you have billed with a referring/ordering provider tha… | Details → |
| N545 | Payment reduced based on status as an unsuccessful eprescriber per the Electronic Pre… | Details → |
| N545 | Payment reduced based on status as an unsuccessful eprescriber per the Electronic Pre… | Details → |
| N546 | Payment represents a previous reduction based on the Electronic Prescribing (eRx) Inc… | Details → |
| N546 | Payment represents a previous reduction based on the Electronic Prescribing (eRx) Inc… | Details → |
| N547 | A refund request (Frequency Type Code 8) was processed previously. | Details → |
| N547 | A refund request (Frequency Type Code 8) was processed previously. | Details → |
| N548 | Alert: Patient's calendar year deductible has been met. | Details → |
| N548 | Alert: Patient's calendar year deductible has been met. | Details → |
| N549 | Alert: Patient's calendar year out-of-pocket maximum has been met. | Details → |
| N549 | Alert: Patient's calendar year out-of-pocket maximum has been met. | Details → |
| N55 | Procedures for billing with group/referring/performing providers were not followed. | Details → |
| N55 | Procedures for billing with group/referring/performing providers were not followed. | Details → |
| N550 | Alert: You have not responded to requests to revalidate your provider/supplier enroll… | Details → |
| N550 | Alert: You have not responded to requests to revalidate your provider/supplier enroll… | Details → |
| N551 | Payment adjusted based on the Ambulatory Surgical Center (ASC) Quality Reporting Prog… | Details → |
| N551 | Payment adjusted based on the Ambulatory Surgical Center (ASC) Quality Reporting Prog… | Details → |
| N552 | Payment adjusted to reverse a previous withhold/bonus amount. | Details → |
| N552 | Payment adjusted to reverse a previous withhold/bonus amount. | Details → |
| N553 | Payment adjusted based on a Low Income Subsidy (LIS) retroactive coverage or status c… | Details → |
| N553 | Payment adjusted based on a Low Income Subsidy (LIS) retroactive coverage or status c… | Details → |
| N554 | Missing/Incomplete/Invalid Family Planning Indicator. | Details → |
| N554 | Missing/Incomplete/Invalid Family Planning Indicator. | Details → |
| N555 | Missing medication list. | Details → |
| N555 | Missing medication list. | Details → |
| N556 | Incomplete/invalid medication list. | Details → |
| N556 | Incomplete/invalid medication list. | Details → |
| N557 | This claim/service is not payable under our service area. The claim must be filed to … | Details → |
| N557 | This claim/service is not payable under our service area. The claim must be filed to … | 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.