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 |
|---|---|---|
| N189 | Alert: This service has been paid as a one-time exception to the plan's benefit restr… | Details → |
| N19 | Procedure code incidental to primary procedure. | Details → |
| N19 | Procedure code incidental to primary procedure. | Details → |
| N190 | Missing contract indicator. | Details → |
| N190 | Missing contract indicator. | Details → |
| N191 | The provider must update insurance information directly with payer. | Details → |
| N191 | The provider must update insurance information directly with payer. | Details → |
| N192 | Alert: Patient is a Medicaid/Qualified Medicare Beneficiary. | Details → |
| N192 | Alert: Patient is a Medicaid/Qualified Medicare Beneficiary. | Details → |
| N193 | Alert: Specific federal/state/local program may cover this service through another pa… | Details → |
| N193 | Alert: Specific federal/state/local program may cover this service through another pa… | Details → |
| N194 | Technical component not paid if provider does not own the equipment used. | Details → |
| N194 | Technical component not paid if provider does not own the equipment used. | Details → |
| N195 | The technical component must be billed separately. | Details → |
| N195 | The technical component must be billed separately. | Details → |
| N196 | Alert: Patient eligible to apply for other coverage which may be primary. | Details → |
| N196 | Alert: Patient eligible to apply for other coverage which may be primary. | Details → |
| N197 | The subscriber must update insurance information directly with payer. | Details → |
| N197 | The subscriber must update insurance information directly with payer. | Details → |
| N198 | Rendering provider must be affiliated with the pay-to provider. | Details → |
| N198 | Rendering provider must be affiliated with the pay-to provider. | Details → |
| N199 | Additional payment/recoupment approved based on payer-initiated review/audit. | Details → |
| N199 | Additional payment/recoupment approved based on payer-initiated review/audit. | Details → |
| N2 | This allowance has been made in accordance with the most appropriate course of treatm… | Details → |
| N2 | This allowance has been made in accordance with the most appropriate course of treatm… | Details → |
| N20 | Service not payable with other service rendered on the same date. | Details → |
| N20 | Service not payable with other service rendered on the same date. | Details → |
| N20 | Item billed is included in allowance of other service provided on the same date | Details → |
| N200 | The professional component must be billed separately. | Details → |
| N200 | The professional component must be billed separately. | Details → |
| N201 | A mental health facility is responsible for payment of outside providers who furnish … | Details → |
| N201 | A mental health facility is responsible for payment of outside providers who furnish … | Details → |
| N202 | Alert: Additional information/explanation will be sent separately. | Details → |
| N202 | Alert: Additional information/explanation will be sent separately. | Details → |
| N203 | Missing/incomplete/invalid anesthesia time/units. | Details → |
| N203 | Missing/incomplete/invalid anesthesia time/units. | Details → |
| N204 | Services under review for possible pre-existing condition. Send medical records for p… | Details → |
| N204 | Services under review for possible pre-existing condition. Send medical records for p… | Details → |
| N205 | Information provided was illegible. | Details → |
| N205 | Information provided was illegible. | Details → |
| N206 | The supporting documentation does not match the information sent on the claim. | Details → |
| N206 | The supporting documentation does not match the information sent on the claim. | Details → |
| N207 | Missing/incomplete/invalid weight. | Details → |
| N207 | Missing/incomplete/invalid weight. | Details → |
| N208 | Missing/incomplete/invalid DRG code. | Details → |
| N208 | Missing/incomplete/invalid DRG code. | Details → |
| N209 | Missing/incomplete/invalid taxpayer identification number (TIN). | Details → |
| N209 | Missing/incomplete/invalid taxpayer identification number (TIN). | Details → |
| N21 | Alert: Your line item has been separated into multiple lines to expedite handling. | Details → |
| N21 | Alert: Your line item has been separated into multiple lines to expedite handling. | Details → |
| N210 | Alert: You may appeal this decision. | Details → |
| N210 | Alert: You may appeal this decision. | Details → |
| N210 | Precertification/authorization/notification/pre-treatment absent Alert: You may appe… | Details → |
| N211 | Alert: You may not appeal this decision. | Details → |
| N211 | Procedure/service was partially or fully furnished by another provider. This item is… | Details → |
| N211 | Alert: You may not appeal this decision. | Details → |
| N211 | The time limit for filing has expired. You may not appeal this decision. | Details → |
| N211 | Non-covered charge(s). This service was processed in accordance with rules and guide… | Details → |
| N212 | Charges processed under a Point of Service benefit. | Details → |
| N212 | Charges processed under a Point of Service benefit. | 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.