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 |
|---|---|---|
| 404 | Provider number is not active for dos billed. | Details → |
| 405 | Rebill: Performing provider name/number and group name must be in box 31 or 33 on new… | Details → |
| 406 | Denied. Provider does not have a valid, active license for service dates billed. | Details → |
| 407 | Bill not payable at this time/reopening is in provisional status pending further dete… | Details → |
| 408 | Payment made for treatment of allowed condition(s) only. Bill injured worker for nonc… | Details → |
| 409 | Compounded prescription only paid. Rebill non-NDC items on Statement for Miscellaneou… | Details → |
| 410 | Total mileage charge calculated at the current L&I rate. | Details → |
| 411 | Rejection of this claim has been overturned. Claim has now been allowed by L&I. | Details → |
| 412 | Claim is in appeal process before the Board of Industrial Insurance Appeals (BIIA). P… | Details → |
| 413 | Denied. Professional interpret of this service payable only if test done in inpatient… | Details → |
| 414 | Repayment due to audit decision that has been reversed by L&I. | Details → |
| 415 | Bill has been paid by A-19. Questions concerning this transaction should contact dedu… | Details → |
| 416 | Denied. This reopening application has been billed by and paid to the attending physi… | Details → |
| 417 | Denied. These services need to be rebilled under the appropriate claim number. | Details → |
| 418 | Payment made to correct your account for the duplicate refund submitted to L&I. | Details → |
| 419 | There were no duplicate payments. You were posting from a credit balance remittance a… | Details → |
| 420 | Deduction taken. Treatment rendered after 30 visit maximum. | Details → |
| 421 | Please refer to the notification of potential DRG sent in regard to this bill. | Details → |
| 422 | Denied. Only procedures 99080, 99083 and 99084 are payable under this provider number… | Details → |
| 423 | Lack of the provider number will result in delayed payment and/or return of your bill… | Details → |
| 424 | Denied. Compensation not payable when the time lost from work was less than 4 hours. | Details → |
| 425 | Note the correction to this ICD diagnosis code. The code was incorrectly billed. | Details → |
| 426 | Denied. This code is not payable in combination with codes 97530 or 97531. | Details → |
| 427 | Bill suspended. Submitter not authorized to submit bills for this provider. Call 360-… | Details → |
| 428 | Outpatient service within 24 hrs of an admit paid by DRG method is considered already… | Details → |
| 429 | Denied. Services requested by the injured worker's attorney must be billed to the att… | Details → |
| 430 | Denied. Consultation code not payable to a practitioner providing ongoing care. | Details → |
| 431 | Autopsy bill with no claim number. Refer to service date and first 2 letters of last … | Details → |
| 432 | 50% of allowable charges paid. Bill balance to employer under self insured claim numb… | Details → |
| 433 | Denied. If service rendered was a rating exam, rebill with procedure code 1106M. | Details → |
| 434 | Denied. Tax not payable when related charges are denied. | Details → |
| 435 | Maximum allowable fee for this service has been paid. Payment for this line item is r… | Details → |
| 436 | Prior authorization (PA) number on bill invalid for this claim number and/or admit. | Details → |
| 437 | Denied per WAC 296-20-03001, no more than 6 injections will be authorized per injured… | Details → |
| 438 | Bill paid. Please remove injured worker from collections. | Details → |
| 439 | Denied. Massage services that are part of a treatment plan ordered by a doctor are ex… | Details → |
| 440 | Denied. Provider's application to treat injured workers has been denied. | Details → |
| 441 | Denied. Bills for copies of records must be submitted by the provider performing the … | Details → |
| 442 | Denied. Provider was suspended or was not enrolled on date of service. | Details → |
| 443 | Missing/Invalid patient paid amount. Clmt paid amount is greater than total charge or… | Details → |
| 444 | Refund made as a result of audit penalty imposed on the provider. | Details → |
| 445 | Denied. Claim ID field has blanks and/or invalid data. Call 1-800-831-5227 to confirm… | Details → |
| 446 | Denied. This bill was in the bill suspense file for over 2 years and has become outda… | Details → |
| 447 | Denied. This supply/service is bundled into another procedure. | Details → |
| 448 | Base code paid within endoscopic arthroscopic family code. | Details → |
| 449 | Denied. No retraining bills are payable during a plan interrupt. | Details → |
| 450 | Denied. The admittance date is not within the date span for the billed notification (… | Details → |
| 451 | Denied. The 10 digit prior authorization (PA) number is for an admission denied by L&… | Details → |
| 452 | Denied. The prior authorization (PA) number on the bill is not a valid number for thi… | Details → |
| 453 | Denied. L&I has not received the required documentation for this admission. | Details → |
| 454 | For admit dates of July 18, 1988 and after include the prior authorization number in … | Details → |
| 455 | Outpatient service within 24 hrs of an admit must be billed as inpatient on the inpat… | Details → |
| 456 | This readmission/transfer has been denied as a result of a medical review. | Details → |
| 457 | Denied. CPT coding was on the bill. Pain clinic service must be billed by revenue cod… | Details → |
| 458 | We have changed the units billed to 1 and paid the procedure at the rate for 1 unit o… | Details → |
| 459 | Excessive units of service were billed. Enter 1 unit for each time the procedure was … | Details → |
| 460 | Denied. A telephone call to your office verified that errors were made in the charges… | Details → |
| 461 | Denied. Immunization procedures include the cost of materials. | Details → |
| 462 | Denied. Procedure 97261 is payable only when an additional area of the body is manipu… | Details → |
| 463 | Denied. Payment for room accommodation charge for the date of discharge is not payabl… | 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.