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 |
|---|---|---|
| P17 | Referral not authorized by attending physician per regulatory requirement. To be used… | Details → |
| P17 | Service was paid on a more recent invoice sent to L&I. | Details → |
| P18 | Procedure is not listed in the jurisdiction fee schedule. An allowance has been made … | Details → |
| P18 | Our records indicate your internship dates have ended. | Details → |
| P19 | Procedure has a relative value of zero in the jurisdiction fee schedule, therefore no… | Details → |
| P2 | Not a work related injury/illness and thus not the liability of the workers' compensa… | Details → |
| P20 | Service not paid under jurisdiction allowed outpatient facility fee schedule. To be u… | Details → |
| P20 | This transaction transfers your debt to L&I Collections. | Details → |
| P21 | Payment denied based on the Medical Payments Coverage (MPC) and/or Personal Injury Pr… | Details → |
| P21 | Payment is applied to the payee's debt recorded with L&I Collections. | Details → |
| P22 | Payment adjusted based on the Medical Payments Coverage (MPC) and/or Personal Injury … | Details → |
| P22 | Denied. This service has already been billed by and paid to the provider of service. | Details → |
| P23 | Medical Payments Coverage (MPC) or Personal Injury Protection (PIP) Benefits jurisdic… | Details → |
| P23 | Processed per L&I Pharmacy Consultant. | Details → |
| P24 | Payment adjusted based on Preferred Provider Organization (PPO). Usage: If adjustment… | Details → |
| P24 | ICN adjusted due to payee/provider number relationship error. | Details → |
| P25 | Payment adjusted based on Medical Provider Network (MPN). Usage: If adjustment is at … | Details → |
| P25 | This procedure code is not payable on the same day as the IME. | Details → |
| P26 | Payment adjusted based on Voluntary Provider network (VPN). Usage: If adjustment is a… | Details → |
| P26 | Add on procedures must be billed with primary code. | Details → |
| P27 | Payment denied based on the Liability Coverage Benefits jurisdictional regulations an… | Details → |
| P27 | PT (97001-97799) not payable to chiropractors. Refer to WA State Fee Schedule to dete… | Details → |
| P28 | Payment adjusted based on the Liability Coverage Benefits jurisdictional regulations … | Details → |
| P28 | Denied. Rental is monthly. One month or less = 1 unit of service. # of units = # of r… | Details → |
| P29 | Liability Benefits jurisdictional fee schedule adjustment. Usage: If adjustment is at… | Details → |
| P29 | Denied. 1 day is = to 1 unit of svc. The # of units must equal the # of rental days c… | Details → |
| P3 | Workers' Compensation case settled. Patient is responsible for amount of this claim/s… | Details → |
| P30 | Payment denied for exacerbation when supporting documentation was not complete. To be… | Details → |
| P30 | Denied. Modifier -7N may only be used with X-ray, lab services, and other allowed dia… | Details → |
| P31 | Payment denied for exacerbation when treatment exceeds time allowed. To be used for P… | Details → |
| P31 | Denied. Provider does not have valid credentials for date of service billed. | Details → |
| P32 | Denied. Procedure undergoing review. | Details → |
| P32 | Payment adjusted due to Apportionment. Start: 08/01/2022 | Details → |
| P33 | Denied. This procedure is only payable when billed with an IME exam code. | Details → |
| P34 | Payment processed per Operations/MIPS Manager's authorization. | Details → |
| P35 | Not valid for version of OCE software currently installed by L&I. Adjustments will be… | Details → |
| P36 | Do not send adjustment, submit new bill. | Details → |
| P37 | Denial processed per Operations/MIPS Manager's authorization. | Details → |
| P38 | L&I is returning your refund. Your refund is in excess of the amount required per you… | Details → |
| P39 | Denied. 1071M cannot be billed without an activity prescription form code. Please cor… | Details → |
| P4 | Workers' Compensation claim adjudicated as non-compensable. This Payer not liable for… | Details → |
| P40 | Payment made per special arrangement. | Details → |
| P41 | Denied. Q1003 must be billed with 66982 - 66986. | Details → |
| P42 | Payment of this service has been made per Superior Court. | Details → |
| P43 | Denied. 2 monaural hearing aids dispensed on the same day. Rebill with binaural dispe… | Details → |
| P44 | Denied. 2 monaural hearing aids dispensed on the same day. Rebill with binaural heari… | Details → |
| P45 | Denied. Locum Tenens providers must use their own provider account numbers without th… | Details → |
| P46 | NPI is not registered with L&I. Call Provider Credentialing at 360-902-5140 or bill u… | Details → |
| P47 | Denied. Report of Accident (ROA) is limited to 1 per provider per claim. | Details → |
| P48 | Modifiers billed are not payable in combination. | Details → |
| P49 | 12 visits paid. Over 12 visits require auth; over 24 visits require UR. See WWW.LNI.W… | Details → |
| P5 | Based on payer reasonable and customary fees. No maximum allowable defined by legisla… | Details → |
| P50 | Denied. Treatment not authorized or has exceeded authorized visits. Contact Qualis He… | Details → |
| P51 | Denied. Please submit one bill using one office visit level and list all claims in Bo… | Details → |
| P52 | Denied. Payment denied as result of provider audit. | Details → |
| P53 | Bill adjusted due to L&I policy change. | Details → |
| P54 | ASC bundled service. | Details → |
| P55 | Denied. Please rebill with an unaltered invoice/packing slip from the buying company … | Details → |
| P56 | This charge has been processed per L&I Occupational Nurse Consultant. | Details → |
| P57 | When billing for procedure 99080 with E/M service, a separate chart note and report a… | 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.