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 |
|---|---|---|
| N213 | Missing/incomplete/invalid facility/discrete unit DRG/DRG exempt status information. | Details → |
| N213 | Missing/incomplete/invalid facility/discrete unit DRG/DRG exempt status information. | Details → |
| N214 | Missing/incomplete/invalid history of the related initial surgical procedure(s). | Details → |
| N214 | Missing/incomplete/invalid history of the related initial surgical procedure(s). | Details → |
| N215 | Alert: A payer providing supplemental or secondary coverage shall not require a claim… | Details → |
| N215 | Alert: A payer providing supplemental or secondary coverage shall not require a claim… | Details → |
| N216 | We do not offer coverage for this type of service or the patient is not enrolled in t… | Details → |
| N216 | We do not offer coverage for this type of service or the patient is not enrolled in t… | Details → |
| N217 | We pay only one site of service per provider per claim. | Details → |
| N217 | We pay only one site of service per provider per claim. | Details → |
| N218 | You must furnish and service this item for as long as the patient continues to need i… | Details → |
| N218 | You must furnish and service this item for as long as the patient continues to need i… | Details → |
| N219 | Payment based on previous payer's allowed amount. | Details → |
| N219 | Payment based on previous payer's allowed amount. | Details → |
| N22 | Alert: This procedure code was added/changed because it more accurately describes the… | Details → |
| N22 | Alert: This procedure code was added/changed because it more accurately describes the… | Details → |
| N220 | Alert: See the payer's web site or contact the payer's Customer Service department to… | Details → |
| N220 | Alert: See the payer's web site or contact the payer's Customer Service department to… | Details → |
| N221 | Missing Admitting History and Physical report. | Details → |
| N221 | Missing Admitting History and Physical report. | Details → |
| N222 | Incomplete/invalid Admitting History and Physical report. | Details → |
| N222 | Incomplete/invalid Admitting History and Physical report. | Details → |
| N223 | Missing documentation of benefit to the patient during initial treatment period. | Details → |
| N223 | Missing documentation of benefit to the patient during initial treatment period. | Details → |
| N224 | Incomplete/invalid documentation of benefit to the patient during initial treatment p… | Details → |
| N224 | Incomplete/invalid documentation of benefit to the patient during initial treatment p… | Details → |
| N225 | Incomplete/invalid documentation/orders/notes/summary/report/chart. | Details → |
| N225 | Incomplete/invalid documentation/orders/notes/summary/report/chart. | Details → |
| N226 | Incomplete/invalid American Diabetes Association Certificate of Recognition. | Details → |
| N226 | Incomplete/invalid American Diabetes Association Certificate of Recognition. | Details → |
| N227 | Incomplete/invalid Certificate of Medical Necessity. | Details → |
| N227 | Incomplete/invalid Certificate of Medical Necessity. | Details → |
| N228 | Incomplete/invalid consent form. | Details → |
| N228 | Incomplete/invalid consent form. | Details → |
| N229 | Incomplete/invalid contract indicator. | Details → |
| N229 | Incomplete/invalid contract indicator. | Details → |
| N23 | Alert: Patient liability may be affected due to coordination of benefits with other c… | Details → |
| N23 | Alert: Patient liability may be affected due to coordination of benefits with other c… | Details → |
| N230 | Incomplete/invalid indication of whether the patient owns the equipment that requires… | Details → |
| N230 | Incomplete/invalid indication of whether the patient owns the equipment that requires… | Details → |
| N231 | Incomplete/invalid invoice or statement certifying the actual cost of the lens, less … | Details → |
| N231 | Incomplete/invalid invoice or statement certifying the actual cost of the lens, less … | Details → |
| N232 | Incomplete/invalid itemized bill/statement. | Details → |
| N232 | Incomplete/invalid itemized bill/statement. | Details → |
| N233 | Incomplete/invalid operative note/report. | Details → |
| N233 | Incomplete/invalid operative note/report. | Details → |
| N234 | Incomplete/invalid oxygen certification/re-certification. | Details → |
| N234 | Incomplete/invalid oxygen certification/re-certification. | Details → |
| N235 | Incomplete/invalid pacemaker registration form. | Details → |
| N235 | Incomplete/invalid pacemaker registration form. | Details → |
| N236 | Incomplete/invalid pathology report. | Details → |
| N236 | Incomplete/invalid pathology report. | Details → |
| N237 | Incomplete/invalid patient medical record for this service. | Details → |
| N237 | Incomplete/invalid patient medical record for this service. | Details → |
| N238 | Incomplete/invalid physician certified plan of care. | Details → |
| N238 | Incomplete/invalid physician certified plan of care. | Details → |
| N239 | Incomplete/invalid physician financial relationship form. | Details → |
| N239 | Incomplete/invalid physician financial relationship form. | Details → |
| N24 | Missing/incomplete/invalid Electronic Funds Transfer (EFT) banking information. | Details → |
| N24 | Missing/incomplete/invalid Electronic Funds Transfer (EFT) banking information. | 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.