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 |
|---|---|---|
| M5 | Monthly rental payments can continue until the earlier of the 15th month from the fir… | Details → |
| M5 | Monthly rental payments can continue until the earlier of the 15th month from the fir… | Details → |
| M50 | Missing/incomplete/invalid revenue code(s). | Details → |
| M50 | Missing/incomplete/invalid revenue code(s). | Details → |
| M51 | Missing/incomplete/invalid procedure code(s). | Details → |
| M51 | Claim/service lacks information or has submission/billing error(s) Missing/incomplet… | Details → |
| M51 | Missing/incomplete/invalid procedure code(s). | Details → |
| M52 | Missing/incomplete/invalid 'from' date(s) of service. | Details → |
| M52 | Missing/incomplete/invalid 'from' date(s) of service. | Details → |
| M53 | Missing/incomplete/invalid days or units of service. | Details → |
| M53 | Missing/incomplete/invalid days or units of service. | Details → |
| M54 | Missing/incomplete/invalid total charges. | Details → |
| M54 | Missing/incomplete/invalid total charges. | Details → |
| M55 | We do not pay for self-administered anti-emetic drugs that are not administered with … | Details → |
| M55 | We do not pay for self-administered anti-emetic drugs that are not administered with … | Details → |
| M56 | Missing/incomplete/invalid payer identifier. | Details → |
| M56 | Missing/incomplete/invalid payer identifier. | Details → |
| M57 | Missing/incomplete/invalid provider identifier. | Details → |
| M57 | Missing/incomplete/invalid provider identifier. | Details → |
| M58 | Missing/incomplete/invalid claim information. Resubmit claim after corrections. | Details → |
| M58 | Missing/incomplete/invalid claim information. Resubmit claim after corrections. | Details → |
| M59 | Missing/incomplete/invalid 'to' date(s) of service. | Details → |
| M59 | Missing/incomplete/invalid 'to' date(s) of service. | Details → |
| M6 | Alert: You must furnish and service this item for any period of medical need for the … | Details → |
| M6 | Alert: You must furnish and service this item for any period of medical need for the … | Details → |
| M60 | Missing Certificate of Medical Necessity. | Details → |
| M60 | Claim/service lacks information or has submission/billing error(s) Missing Certifica… | Details → |
| M60 | Missing Certificate of Medical Necessity. | Details → |
| M61 | We cannot pay for this as the approval period for the FDA clinical trial has expired. | Details → |
| M61 | We cannot pay for this as the approval period for the FDA clinical trial has expired. | Details → |
| M62 | Missing/incomplete/invalid treatment authorization code. | Details → |
| M62 | Missing/incomplete/invalid treatment authorization code. | Details → |
| M63 | We do not pay for more than one of these on the same day. | Details → |
| M63 | We do not pay for more than one of these on the same day. | Details → |
| M64 | Missing/incomplete/invalid other diagnosis. | Details → |
| M64 | Missing/incomplete/invalid other diagnosis. | Details → |
| M65 | One interpreting physician charge can be submitted per claim when a purchased diagnos… | Details → |
| M65 | One interpreting physician charge can be submitted per claim when a purchased diagnos… | Details → |
| M66 | Our records indicate that you billed diagnostic tests subject to price limitations an… | Details → |
| M66 | Our records indicate that you billed diagnostic tests subject to price limitations an… | Details → |
| M67 | Missing/incomplete/invalid other procedure code(s). | Details → |
| M67 | Missing/incomplete/invalid other procedure code(s). | Details → |
| M68 | Missing/incomplete/invalid attending, ordering, rendering, supervising or referring p… | Details → |
| M68 | Missing/incomplete/invalid attending, ordering, rendering, supervising or referring p… | Details → |
| M69 | Paid at the regular rate as you did not submit documentation to justify the modified … | Details → |
| M69 | Paid at the regular rate as you did not submit documentation to justify the modified … | Details → |
| M7 | No rental payments after the item is purchased, returned or after the total of issued… | Details → |
| M7 | No rental payments after the item is purchased, returned or after the total of issued… | Details → |
| M70 | Alert: The NDC code submitted for this service was translated to a HCPCS code for pro… | Details → |
| M70 | Alert: The NDC code submitted for this service was translated to a HCPCS code for pro… | Details → |
| M71 | Total payment reduced due to overlap of tests billed. | Details → |
| M71 | Total payment reduced due to overlap of tests billed. | Details → |
| M72 | Did not enter full 8-digit date (MM/DD/CCYY). | Details → |
| M72 | Did not enter full 8-digit date (MM/DD/CCYY). | Details → |
| M73 | The HPSA/Physician Scarcity bonus can only be paid on the professional component of t… | Details → |
| M73 | The HPSA/Physician Scarcity bonus can only be paid on the professional component of t… | Details → |
| M74 | This service does not qualify for a HPSA/Physician Scarcity bonus payment. | Details → |
| M74 | This service does not qualify for a HPSA/Physician Scarcity bonus payment. | Details → |
| M75 | Multiple automated multichannel tests performed on the same day combined for payment. | Details → |
| M75 | Multiple automated multichannel tests performed on the same day combined for payment. | 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.