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 |
|---|---|---|
| MA02 | Alert: If you do not agree with this determination, you have the right to appeal. You… | Details → |
| MA03 | If you do not agree with the approved amounts and $100 or more is in dispute (less de… | Details → |
| MA03 | If you do not agree with the approved amounts and $100 or more is in dispute (less de… | Details → |
| MA04 | Secondary payment cannot be considered without the identity of or payment information… | Details → |
| MA04 | Secondary payment cannot be considered without the identity of or payment information… | Details → |
| MA04 | This claim appears to be covered by a primary payer. The primary payerinformation was… | Details → |
| MA05 | Incorrect admission date patient status or type of bill entry on claim. | Details → |
| MA05 | Incorrect admission date patient status or type of bill entry on claim. | Details → |
| MA06 | Missing/incomplete/invalid beginning and/or ending date(s). | Details → |
| MA06 | Missing/incomplete/invalid beginning and/or ending date(s). | Details → |
| MA07 | Alert: The claim information has also been forwarded to Medicaid for review. | Details → |
| MA07 | Alert: The claim information has also been forwarded to Medicaid for review. | Details → |
| MA08 | Alert: Claim information was not forwarded because the supplemental coverage is not w… | Details → |
| MA08 | Alert: Claim information was not forwarded because the supplemental coverage is not w… | Details → |
| MA09 | Alert: Claim submitted as unassigned but processed as assigned in accordance with our… | Details → |
| MA09 | Alert: Claim submitted as unassigned but processed as assigned in accordance with our… | Details → |
| MA10 | Alert: The patient's payment was in excess of the amount owed. You must refund the ov… | Details → |
| MA10 | Alert: The patient's payment was in excess of the amount owed. You must refund the ov… | Details → |
| MA100 | Missing/incomplete/invalid date of current illness or symptoms. | Details → |
| MA100 | Missing/incomplete/invalid date of current illness or symptoms. | Details → |
| MA101 | A Skilled Nursing Facility (SNF) is responsible for payment of outside providers who … | Details → |
| MA101 | A Skilled Nursing Facility (SNF) is responsible for payment of outside providers who … | Details → |
| MA102 | Missing/incomplete/invalid name or provider identifier for the rendering/referring/ o… | Details → |
| MA102 | Missing/incomplete/invalid name or provider identifier for the rendering/referring/ o… | Details → |
| MA103 | Hemophilia Add On. | Details → |
| MA103 | Hemophilia Add On. | Details → |
| MA104 | Missing/incomplete/invalid date the patient was last seen or the provider identifier … | Details → |
| MA104 | Missing/incomplete/invalid date the patient was last seen or the provider identifier … | Details → |
| MA105 | Missing/incomplete/invalid provider number for this place of service. | Details → |
| MA105 | Missing/incomplete/invalid provider number for this place of service. | Details → |
| MA106 | PIP (Periodic Interim Payment) claim. | Details → |
| MA106 | PIP (Periodic Interim Payment) claim. | Details → |
| MA107 | Paper claim contains more than three separate data items in field 19. | Details → |
| MA107 | Paper claim contains more than three separate data items in field 19. | Details → |
| MA108 | Paper claim contains more than one data item in field 23. | Details → |
| MA108 | Paper claim contains more than one data item in field 23. | Details → |
| MA109 | Claim processed in accordance with ambulatory surgical guidelines. | Details → |
| MA109 | Claim processed in accordance with ambulatory surgical guidelines. | Details → |
| MA11 | Payment is being issued on a conditional basis. If no-fault insurance, liability insu… | Details → |
| MA11 | Payment is being issued on a conditional basis. If no-fault insurance, liability insu… | Details → |
| MA110 | Missing/incomplete/invalid information on whether the diagnostic test(s) were perform… | Details → |
| MA110 | Missing/incomplete/invalid information on whether the diagnostic test(s) were perform… | Details → |
| MA111 | Missing/incomplete/invalid purchase price of the test(s) and/or the performing labora… | Details → |
| MA111 | Missing/incomplete/invalid purchase price of the test(s) and/or the performing labora… | Details → |
| MA112 | Missing/incomplete/invalid group practice information. | Details → |
| MA112 | Missing/incomplete/invalid group practice information. | Details → |
| MA113 | Incomplete/invalid taxpayer identification number (TIN) submitted by you per the Inte… | Details → |
| MA113 | Incomplete/invalid taxpayer identification number (TIN) submitted by you per the Inte… | Details → |
| MA114 | Missing/incomplete/invalid information on where the services were furnished. | Details → |
| MA114 | Missing/incomplete/invalid information on where the services were furnished. | Details → |
| MA115 | Missing/incomplete/invalid physical location (name and address, or PIN) where the ser… | Details → |
| MA115 | Missing/incomplete/invalid physical location (name and address, or PIN) where the ser… | Details → |
| MA116 | Did not complete the statement 'Homebound' on the claim to validate whether laborator… | Details → |
| MA116 | Did not complete the statement 'Homebound' on the claim to validate whether laborator… | Details → |
| MA117 | This claim has been assessed a $1.00 user fee. | Details → |
| MA117 | This claim has been assessed a $1.00 user fee. | Details → |
| MA118 | Alert: No Medicare payment issued for this claim for services or supplies furnished t… | Details → |
| MA118 | Alert: No Medicare payment issued for this claim for services or supplies furnished t… | Details → |
| MA119 | Provider level adjustment for late claim filing applies to this claim. | Details → |
| MA119 | Provider level adjustment for late claim filing applies to this claim. | 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.