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 |
|---|---|---|
| A92 | Denied. Second diagnosis code invalid per code editor. | Details → |
| A93 | Denied. Third diagnosis code invalid per code editor. | Details → |
| A94 | Denied. Fourth diagnosis code invalid per code editor. | Details → |
| A95 | Denied. Fifth diagnosis code invalid per code editor. | Details → |
| A96 | Denied. Sixth diagnosis code invalid per code editor. | Details → |
| A97 | Denied. L&I accepts only hospital outpatient types of bill 131 through 134 on CMS-145… | Details → |
| A98 | Denied. Per Outpatient Code Editor (OCE), procedure lacks required radio labeled prod… | Details → |
| B01 | Denied. Procedure code specific to your State. Refer to Washington State fee schedule… | Details → |
| B02 | Denied. ICN on adjustment form does not match the bill ICN you are trying to adjust. … | Details → |
| B03 | Denied. Only one bill ICN can be adjusted per provider's request for adjustment form. | Details → |
| B04 | Modifier -99 should only be used when 2 or more modifiers affect payment. Doing so ma… | Details → |
| B05 | Denied. Injured worker's lost time is not sufficient to justify this procedure. | Details → |
| B06 | Denied. Prescribing provider's number and name on bill does not match. | Details → |
| B07 | Adjustment due to NSF check. | Details → |
| B08 | This line was manually priced due to a partial refund. | Details → |
| B09 | Denied. Service billed is unrelated to this claim number/injured worker. | Details → |
| B1 | Non-covered visits. Start: 01/01/1995 | Details → |
| B10 | Allowed amount has been reduced because a component of the basic procedure/test was p… | Details → |
| B10 | No bills are payable due to the rejection reason on this claim. | Details → |
| B11 | The claim/service has been transferred to the proper payer/processor for processing. … | Details → |
| B11 | Denied. Procedure code 76005 not payable in conjunction with these services. | Details → |
| B12 | Services not documented in patient's medical records. Start: 01/01/1995 | Last Modif… | Details → |
| B12 | Paid per L&I Claims Consultant. | Details → |
| B13 | Previously paid. Payment for this claim/service may have been provided in a previous … | Details → |
| B13 | Paid. Procedure now allowed. | Details → |
| B14 | Only one visit or consultation per physician per day is covered. Start: 01/01/1995 |… | Details → |
| B14 | Denied. Procedure code 72275 not payable with 64470-64476. | Details → |
| B15 | This service/procedure requires that a qualifying service/procedure be received and c… | Details → |
| B15 | This service/procedure requires that a qualifying service/procedure be received and c… | Details → |
| B15 | Place of service was changed to reflect actual site of service. | Details → |
| B16 | 'New Patient' qualifications were not met. Start: 01/01/1995 | Last Modified: 09/30/… | Details → |
| B16 | Facility fees are not payable for procedures performed in physician's office. | Details → |
| B17 | Payment adjusted because this service was not prescribed by a physician, not prescrib… | Details → |
| B18 | This procedure code and modifier were invalid on the date of service. Start: 01/01/1… | Details → |
| B19 | Claim/service adjusted because of the finding of a Review Organization. Start: 01/01… | Details → |
| B2 | Covered visits. Start: 01/01/1995 | Stop: 10/16/2003 | Details → |
| B2 | This provider was not certified/eligible to be paid for this procedure/service on thi… | Details → |
| B20 | Item was partially or fully furnished by another provider Was beneficiary inpatient? | Details → |
| B20 | Procedure/service was partially or fully furnished by another provider. Start: 01/01… | Details → |
| B20 | Endoscopy 100. | Details → |
| B21 | The charges were reduced because the service/care was partially furnished by another … | Details → |
| B21 | Endoscopy Minus Base | Details → |
| B22 | This payment is adjusted based on the diagnosis. Start: 01/01/1995 | Last Modified: … | Details → |
| B22 | Endoscopy 100% then multiple surgery rule 100 | Details → |
| B23 | Procedure billed is not authorized per your Clinical Laboratory Improvement Amendment… | Details → |
| B23 | Endoscopy minus base then multiple surgery rule 100 | Details → |
| B24 | Endoscopy 100% then multiple surgery rule 50 | Details → |
| B25 | Endoscopy minus base then multiple surgery rule 50 | Details → |
| B26 | Endoscopy 100% then multiple surgery rule 25 | Details → |
| B27 | Endoscopy minus base then multiple surgery rule 25 | Details → |
| B3 | Covered charges. Start: 01/01/1995 | Stop: 10/16/2003 | Details → |
| B30 | Multiple surgery rule 100 | Details → |
| B31 | Multiple surgery rule 50 | Details → |
| B32 | Multiple surgery rule 25 | Details → |
| B33 | Denied. The required request for additional reimbursement form not received. | Details → |
| B34 | A narrative report of work history is required when billing 1055M. | Details → |
| B4 | Late filing penalty. Start: 01/01/1995 | Details → |
| B40 | The 2nd procedure code modifier is either completely invalid or invalid for the servi… | Details → |
| B41 | The 3rd procedure code modifier is either completely invalid or invalid for the servi… | Details → |
| B42 | The 4th procedure code modifier is either completely invalid or invalid for the servi… | 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.