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 |
|---|---|---|
| N135 | Record fees are the patient's responsibility and limited to the specified co-payment. | Details → |
| N136 | Alert: To obtain information on the process to file an appeal in Arizona, call the De… | Details → |
| N136 | Alert: To obtain information on the process to file an appeal in Arizona, call the De… | Details → |
| N137 | Alert: The provider acting on the Member's behalf, may file an appeal with the Payer.… | Details → |
| N137 | Alert: The provider acting on the Member's behalf, may file an appeal with the Payer.… | Details → |
| N138 | Alert: In the event you disagree with the Dental Advisor's opinion and have additiona… | Details → |
| N138 | Alert: In the event you disagree with the Dental Advisor's opinion and have additiona… | Details → |
| N139 | Alert: Under 32 CFR 199.13, a non-participating provider is not an appropriate appeal… | Details → |
| N139 | Alert: Under 32 CFR 199.13, a non-participating provider is not an appropriate appeal… | Details → |
| N14 | Payment based on a contractual amount or agreement, fee schedule, or maximum allowabl… | Details → |
| N14 | Payment based on a contractual amount or agreement, fee schedule, or maximum allowabl… | Details → |
| N140 | Alert: You have not been designated as an authorized OCONUS provider therefore are no… | Details → |
| N140 | Alert: You have not been designated as an authorized OCONUS provider therefore are no… | Details → |
| N141 | The patient was not residing in a long-term care facility during all or part of the s… | Details → |
| N141 | The patient was not residing in a long-term care facility during all or part of the s… | Details → |
| N142 | The original claim was denied. Resubmit a new claim, not a replacement claim. | Details → |
| N142 | The original claim was denied. Resubmit a new claim, not a replacement claim. | Details → |
| N143 | The patient was not in a hospice program during all or part of the service dates bill… | Details → |
| N143 | The patient was not in a hospice program during all or part of the service dates bill… | Details → |
| N144 | The rate changed during the dates of service billed. | Details → |
| N144 | The rate changed during the dates of service billed. | Details → |
| N145 | Missing/incomplete/invalid provider identifier for this place of service. | Details → |
| N145 | Missing/incomplete/invalid provider identifier for this place of service. | Details → |
| N146 | Missing screening document. | Details → |
| N146 | Missing screening document. | Details → |
| N147 | Long term care case mix or per diem rate cannot be determined because the patient ID … | Details → |
| N147 | Long term care case mix or per diem rate cannot be determined because the patient ID … | Details → |
| N148 | Missing/incomplete/invalid date of last menstrual period. | Details → |
| N148 | Missing/incomplete/invalid date of last menstrual period. | Details → |
| N149 | Rebill all applicable services on a single claim. | Details → |
| N149 | Rebill all applicable services on a single claim. | Details → |
| N15 | Services for a newborn must be billed separately. | Details → |
| N15 | Services for a newborn must be billed separately. | Details → |
| N150 | Missing/incomplete/invalid model number. | Details → |
| N150 | Missing/incomplete/invalid model number. | Details → |
| N151 | Telephone contact services will not be paid until the face-to-face contact requiremen… | Details → |
| N151 | Telephone contact services will not be paid until the face-to-face contact requiremen… | Details → |
| N152 | Missing/incomplete/invalid replacement claim information. | Details → |
| N152 | Missing/incomplete/invalid replacement claim information. | Details → |
| N153 | Missing/incomplete/invalid room and board rate. | Details → |
| N153 | Missing/incomplete/invalid room and board rate. | Details → |
| N154 | Alert: This payment was delayed for correction of provider's mailing address. | Details → |
| N154 | Alert: This payment was delayed for correction of provider's mailing address. | Details → |
| N155 | Alert: Our records do not indicate that other insurance is on file. Please submit oth… | Details → |
| N155 | Alert: Our records do not indicate that other insurance is on file. Please submit oth… | Details → |
| N156 | Alert: The patient is responsible for the difference between the approved treatment a… | Details → |
| N156 | Alert: The patient is responsible for the difference between the approved treatment a… | Details → |
| N157 | Transportation to/from this destination is not covered. | Details → |
| N157 | Transportation to/from this destination is not covered. | Details → |
| N158 | Transportation in a vehicle other than an ambulance is not covered. | Details → |
| N158 | Transportation in a vehicle other than an ambulance is not covered. | Details → |
| N159 | Payment denied/reduced because mileage is not covered when the patient is not in the … | Details → |
| N159 | Payment denied/reduced because mileage is not covered when the patient is not in the … | Details → |
| N16 | Family/member Out-of-Pocket maximum has been met. Payment based on a higher percentag… | Details → |
| N16 | Family/member Out-of-Pocket maximum has been met. Payment based on a higher percentag… | Details → |
| N160 | The patient must choose an option before a payment can be made for this procedure/ eq… | Details → |
| N160 | The patient must choose an option before a payment can be made for this procedure/ eq… | Details → |
| N161 | This drug/service/supply is covered only when the associated service is covered. | Details → |
| N161 | This drug/service/supply is covered only when the associated service is covered. | Details → |
| N162 | Alert: Although your claim was paid, you have billed for a test/specialty not include… | 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.