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 |
|---|---|---|
| N240 | Incomplete/invalid radiology report. | Details → |
| N240 | Incomplete/invalid radiology report. | Details → |
| N241 | Incomplete/invalid review organization approval. | Details → |
| N241 | Incomplete/invalid review organization approval. | Details → |
| N242 | Incomplete/invalid radiology film(s)/image(s). | Details → |
| N242 | Incomplete/invalid radiology film(s)/image(s). | Details → |
| N243 | Incomplete/invalid/not approved screening document. | Details → |
| N243 | Incomplete/invalid/not approved screening document. | Details → |
| N244 | Incomplete/Invalid pre-operative images/visual field results. | Details → |
| N244 | Incomplete/Invalid pre-operative images/visual field results. | Details → |
| N245 | Incomplete/invalid plan information for other insurance. | Details → |
| N245 | Incomplete/invalid plan information for other insurance. | Details → |
| N246 | State regulated patient payment limitations apply to this service. | Details → |
| N246 | State regulated patient payment limitations apply to this service. | Details → |
| N247 | Missing/incomplete/invalid assistant surgeon taxonomy. | Details → |
| N247 | Missing/incomplete/invalid assistant surgeon taxonomy. | Details → |
| N248 | Missing/incomplete/invalid assistant surgeon name. | Details → |
| N248 | Missing/incomplete/invalid assistant surgeon name. | Details → |
| N249 | Missing/incomplete/invalid assistant surgeon primary identifier. | Details → |
| N249 | Missing/incomplete/invalid assistant surgeon primary identifier. | Details → |
| N25 | This company has been contracted by your benefit plan to provide administrative claim… | Details → |
| N25 | This company has been contracted by your benefit plan to provide administrative claim… | Details → |
| N250 | Missing/incomplete/invalid assistant surgeon secondary identifier. | Details → |
| N250 | Missing/incomplete/invalid assistant surgeon secondary identifier. | Details → |
| N251 | Missing/incomplete/invalid attending provider taxonomy. | Details → |
| N251 | Missing/incomplete/invalid attending provider taxonomy. | Details → |
| N252 | Missing/incomplete/invalid attending provider name. | Details → |
| N252 | Missing/incomplete/invalid attending provider name. | Details → |
| N253 | Missing/incomplete/invalid attending provider primary identifier. | Details → |
| N253 | Missing/incomplete/invalid attending provider primary identifier. | Details → |
| N254 | Missing/incomplete/invalid attending provider secondary identifier. | Details → |
| N254 | Missing/incomplete/invalid attending provider secondary identifier. | Details → |
| N255 | Missing/incomplete/invalid billing provider taxonomy. | Details → |
| N255 | Missing/incomplete/invalid billing provider taxonomy. | Details → |
| N256 | Missing/incomplete/invalid billing provider/supplier name. | Details → |
| N256 | Missing/incomplete/invalid billing provider/supplier name. | Details → |
| N257 | Missing/incomplete/invalid billing provider/supplier primary identifier. | Details → |
| N257 | Missing/incomplete/invalid billing provider/supplier primary identifier. | Details → |
| N258 | Missing/incomplete/invalid billing provider/supplier address. | Details → |
| N258 | Missing/incomplete/invalid billing provider/supplier address. | Details → |
| N259 | Missing/incomplete/invalid billing provider/supplier secondary identifier. | Details → |
| N259 | Missing/incomplete/invalid billing provider/supplier secondary identifier. | Details → |
| N26 | Missing itemized bill/statement. | Details → |
| N26 | Missing itemized bill/statement. | Details → |
| N260 | Missing/incomplete/invalid billing provider/supplier contact information. | Details → |
| N260 | Missing/incomplete/invalid billing provider/supplier contact information. | Details → |
| N261 | Missing/incomplete/invalid operating provider name. | Details → |
| N261 | Missing/incomplete/invalid operating provider name. | Details → |
| N262 | Missing/incomplete/invalid operating provider primary identifier. | Details → |
| N262 | Missing/incomplete/invalid operating provider primary identifier. | Details → |
| N263 | Missing/incomplete/invalid operating provider secondary identifier. | Details → |
| N263 | Missing/incomplete/invalid operating provider secondary identifier. | Details → |
| N264 | Missing/incomplete/invalid ordering provider name. | Details → |
| N264 | Missing/incomplete/invalid ordering provider name. | Details → |
| N264 | Item(s) billed did not have a valid ordering physician name | Details → |
| N265 | Missing/incomplete/invalid ordering provider primary identifier. | Details → |
| N265 | Missing/incomplete/invalid ordering provider primary identifier. | Details → |
| N265 | Item(s) billed did not have a valid ordering physician National Provider Identifier (… | Details → |
| N266 | Missing/incomplete/invalid ordering provider address. | Details → |
| N266 | Missing/incomplete/invalid ordering provider address. | 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.