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 |
|---|---|---|
| N372 | Only reasonable and necessary maintenance/service charges are covered. | Details → |
| N373 | It has been determined that another payer paid the services as primary when they were… | Details → |
| N373 | It has been determined that another payer paid the services as primary when they were… | Details → |
| N374 | Primary Medicare Part A insurance has been exhausted and a Part B Remittance Advice i… | Details → |
| N374 | Primary Medicare Part A insurance has been exhausted and a Part B Remittance Advice i… | Details → |
| N375 | Missing/incomplete/invalid questionnaire/information required to determine dependent … | Details → |
| N375 | Missing/incomplete/invalid questionnaire/information required to determine dependent … | Details → |
| N376 | Subscriber/patient is assigned to active military duty, therefore primary coverage ma… | Details → |
| N376 | Subscriber/patient is assigned to active military duty, therefore primary coverage ma… | Details → |
| N377 | Payment based on a processed replacement claim. | Details → |
| N377 | Payment based on a processed replacement claim. | Details → |
| N378 | Missing/incomplete/invalid prescription quantity. | Details → |
| N378 | Missing/incomplete/invalid prescription quantity. | Details → |
| N379 | Claim level information does not match line level information. | Details → |
| N379 | Claim level information does not match line level information. | Details → |
| N38 | Missing/incomplete/invalid place of service. | Details → |
| N38 | Missing/incomplete/invalid place of service. | Details → |
| N380 | The original claim has been processed, submit a corrected claim. | Details → |
| N380 | The original claim has been processed, submit a corrected claim. | Details → |
| N381 | Alert: Consult our contractual agreement for restrictions/billing/payment information… | Details → |
| N381 | Alert: Consult our contractual agreement for restrictions/billing/payment information… | Details → |
| N382 | Missing/incomplete/invalid patient identifier. | Details → |
| N382 | Missing/incomplete/invalid patient identifier. | Details → |
| N382 | Claim/service lacks information or has submission/billing error(s) Missing/incomplet… | Details → |
| N383 | Not covered when deemed cosmetic. | Details → |
| N383 | Not covered when deemed cosmetic. | Details → |
| N384 | Records indicate that the referenced body part/tooth has been removed in a previous p… | Details → |
| N384 | Records indicate that the referenced body part/tooth has been removed in a previous p… | Details → |
| N385 | Notification of admission was not timely according to published plan procedures. | Details → |
| N385 | Notification of admission was not timely according to published plan procedures. | Details → |
| N386 | This decision was based on a National Coverage Determination (NCD). An NCD provides a… | Details → |
| N386 | This decision was based on a National Coverage Determination (NCD). An NCD provides a… | Details → |
| N387 | Alert: Submit this claim to the patient's other insurer for potential payment of supp… | Details → |
| N387 | Alert: Submit this claim to the patient's other insurer for potential payment of supp… | Details → |
| N388 | Missing/incomplete/invalid prescription number. | Details → |
| N388 | Missing/incomplete/invalid prescription number. | Details → |
| N389 | Duplicate prescription number submitted. | Details → |
| N389 | Duplicate prescription number submitted. | Details → |
| N39 | Procedure code is not compatible with tooth number/letter. | Details → |
| N39 | Procedure code is not compatible with tooth number/letter. | Details → |
| N390 | This service/report cannot be billed separately. | Details → |
| N390 | This service/report cannot be billed separately. | Details → |
| N390 | HCPCS code billed is included in the payment/allowance for another service/procedure … | Details → |
| N391 | Missing emergency department records. | Details → |
| N391 | Missing emergency department records. | Details → |
| N392 | Incomplete/invalid emergency department records. | Details → |
| N392 | Incomplete/invalid emergency department records. | Details → |
| N393 | Missing progress notes/report. | Details → |
| N393 | Missing progress notes/report. | Details → |
| N394 | Incomplete/invalid progress notes/report. | Details → |
| N394 | Incomplete/invalid progress notes/report. | Details → |
| N395 | Missing laboratory report. | Details → |
| N395 | Missing laboratory report. | Details → |
| N396 | Incomplete/invalid laboratory report. | Details → |
| N396 | Incomplete/invalid laboratory report. | Details → |
| N397 | Benefits are not available for incomplete service(s)/undelivered item(s). | Details → |
| N397 | Benefits are not available for incomplete service(s)/undelivered item(s). | Details → |
| N398 | Missing elective consent form. | Details → |
| N398 | Missing elective consent form. | Details → |
| N399 | Incomplete/invalid elective consent form. | 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.