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 |
|---|---|---|
| 144 | Incentive adjustment, e.g. preferred product/service. Start: 06/30/2001 | Details → |
| 144 | The prescription written date is missing or is invalid. | Details → |
| 145 | Premium payment withholding Start: 06/30/2002 | Last Modified: 09/30/2007 | Stop: 04… | Details → |
| 145 | Type of service code is missing or is invalid. | Details → |
| 146 | Old Services not billable for the Fiscal Year. | Details → |
| 146 | Diagnosis was invalid for the date(s) of service reported. Start: 06/30/2002 | Last … | Details → |
| 146 | Denied. The injured worker's sex code on this bill is missing or invalid. | Details → |
| 147 | OPPS Code not recognized by OPPS; alternate code for the same service may be availabl… | Details → |
| 147 | Provider contracted/negotiated rate expired or not on file. Start: 06/30/2002 | Details → |
| 147 | The daily room rate was missing from the billing you submitted to L&I. | Details → |
| 148 | CMS Code not recognized by CMS; alternate code for the same service may be available. | Details → |
| 148 | Information from another provider was not provided or was insufficient/incomplete. At… | Details → |
| 148 | The revenue code for this service was missing from the billing you submitted to L&I. | Details → |
| 149 | Not enrolled Member not enrolled on DOS. | Details → |
| 149 | Lifetime benefit maximum has been reached for this service/benefit category. Start: … | Details → |
| 149 | Use of this procedure code for this date of service is invalid. | Details → |
| 150 | Not enrolled group Member was not enrolled with this Medical Group on DOS . | Details → |
| 150 | Payer deems the information submitted does not support this level of service. Start:… | Details → |
| 150 | Denied. Injured worker date of birth is missing or invalid. | Details → |
| 150 | Policy frequency limits may have been reached, per LCD | Details → |
| 151 | Bill on 1500 Resubmit ASC Claims on HCFA ASCs are required to submit claims on form C… | Details → |
| 151 | Payment adjusted because the payer deems the information submitted does not support t… | Details → |
| 151 | The side of body code is invalid. It must be L (left), R (right) B (both) or remain b… | Details → |
| 151 | Equipment is the same or similar to equipment already being used. There is a date sp… | Details → |
| 152 | RUGS Submit with RUGS code. | Details → |
| 152 | Payer deems the information submitted does not support this length of service. Usage:… | Details → |
| 152 | NDC code and/or the prescription number is missing or invalid. | Details → |
| 153 | DevCode Claim lacks required device code. | Details → |
| 153 | Payer deems the information submitted does not support this dosage. Start: 10/31/200… | Details → |
| 153 | Denied. Principal diagnosis code is invalid for the first date of service. | Details → |
| 154 | Report Code is used for reporting performance measurements only. | Details → |
| 154 | Payer deems the information submitted does not support this day's supply. Start: 10/… | Details → |
| 154 | Denied. Second ICD diagnosis code is invalid for the first date of service. | Details → |
| 155 | Invalid G/I- This service code is not valid for Medicare purposes. Medicare uses an a… | Details → |
| 155 | Patient refused the service/procedure. Start: 06/30/2003 | Last Modified: 09/30/2007 | Details → |
| 155 | Drug quantity missing/invalid. If equipment rebill on Statement for Miscellaneous Ser… | Details → |
| 156 | Excl E- This service code is excluded from the Physician fee schedule by regulation. … | Details → |
| 156 | Flexible spending account payments. Note: Use code 187. Start: 09/30/2003 | Last Mod… | Details → |
| 156 | Days supply missing/invalid. If equipment send bill on Statement for Miscellaneous Se… | Details → |
| 157 | No RVU J- This code has no Relative Value Unit and no payment amount. The intent of t… | Details → |
| 157 | Service/procedure was provided as a result of an act of war. Start: 09/30/2003 | Las… | Details → |
| 157 | Not responsible for repair or replacement of contacts or glasses not worn at time of … | Details → |
| 158 | APC Reimbursement for this service is included in the APC reimbursement. | Details → |
| 158 | Service/procedure was provided outside of the United States. Start: 09/30/2003 | Las… | Details → |
| 158 | Bill paid. You must reimburse the employer the total amount he/she paid for this serv… | Details → |
| 159 | DRG Payment for this service is included in the DRG rate. | Details → |
| 159 | Service/procedure was provided as a result of terrorism. Start: 09/30/2003 | Last Mo… | Details → |
| 159 | Prescribing provider number on your bill was terminated or associated to a terminated… | Details → |
| 160 | Age The diagnosis code includes an age range and the age is outside that range. | Details → |
| 160 | Injury/illness was the result of an activity that is a benefit exclusion. Start: 09/… | Details → |
| 160 | Reduced to office call fee for 90030 or ER visit 90350 per our Medical Aid Rules. | Details → |
| 161 | Gender The diagnosis code includes sex designation and the sex does not match. | Details → |
| 161 | Provider performance bonus Start: 02/29/2004 | Details → |
| 161 | Denied. Third ICD diagnosis code is invalid for first date of service. | Details → |
| 162 | E Dx The first letter of the principle diagnosis code in an E. This edit is not appli… | Details → |
| 162 | State-mandated Requirement for Property and Casualty, see Claim Payment Remarks Code … | Details → |
| 162 | Denied. Fourth ICD diagnosis code is invalid for first date of service. | Details → |
| 163 | Gender Match The sex of the patient does not match the sex designated for the procedu… | Details → |
| 163 | Attachment/other documentation referenced on the claim was not received. Start: 06/3… | Details → |
| 163 | Not paid. Diagnosis code missing. | 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.