| MA130 | Claim unprocessable — no appeal rightsMissing Information | CO-16 |
| M20 | HCPCS code missing or invalidMissing Information | CO-16, CO-181 |
| M51 | Procedure code missing or invalidMissing Information | CO-16, CO-181 |
| M76 | Diagnosis missing or invalidMissing Information | CO-16, CO-146 |
| M77 | Place of service missing or wrongMissing Information | CO-5, CO-16 |
| M79 | Charge amount missing or invalidMissing Information | CO-16 |
| M81 | Diagnosis not coded to highest specificityMissing Information | CO-16, CO-146 |
| M119 | NDC missing or invalidMissing Information | CO-16 |
| MA27 | Entitlement number or name invalidMissing Information | CO-16, CO-31, PR-31 |
| MA30 | Type of bill missing or invalidMissing Information | CO-16 |
| MA36 | Patient name missing or invalidMissing Information | CO-16 |
| MA61 | SSN missing or invalidMissing Information | CO-16 |
| MA63 | Principal diagnosis missing or invalidMissing Information | CO-16, CO-146 |
| MA65 | Admitting diagnosis missing or invalidMissing Information | CO-16 |
| MA66 | Principal procedure code missing or invalidMissing Information | CO-16 |
| MA120 | CLIA number missing or invalidMissing Information | CO-16, CO-B7 |
| N382 | Patient identifier missing or invalidMissing Information | CO-16, CO-31 |
| N822 | Procedure modifier missingMissing Information | CO-4, CO-16 |
| N823 | Procedure modifier invalidMissing Information | CO-4, CO-182 |
| N152 | Replacement claim information invalidMissing Information | CO-16 |
| M15 | Services bundled into primary procedureCoding & Bundling | CO-97, CO-236 |
| M80 | Not covered same session as prior serviceCoding & Bundling | CO-97, CO-B15 |
| M86 | Same/similar service paid within timeframeCoding & Bundling | CO-119, CO-151 |
| M144 | Pre/post-op care included in surgical paymentCoding & Bundling | CO-97 |
| N19 | Procedure incidental to primary procedureCoding & Bundling | CO-97 |
| N122 | Add-on code billed without primaryCoding & Bundling | CO-16, CO-107 |
| N56 | Wrong procedure code for service or dateCoding & Bundling | CO-16, CO-181 |
| N525 | Inside another service's global periodCoding & Bundling | CO-97 |
| N657 | Rebill with the appropriate codeCoding & Bundling | CO-16, CO-181 |
| M97 | Paid to facility, not practitioner, for this POSCoding & Bundling | CO-97, CO-58 |
| N30 | Patient ineligible for this serviceCoverage & Eligibility | CO-96, PR-204, CO-177 |
| N130 | Check plan documents for restrictionsCoverage & Eligibility | CO-96, PR-204 |
| N182 | Must bill per the plan's scheduleCoverage & Eligibility | CO-16, CO-24 |
| N351 | Service date outside approved treatment planCoverage & Eligibility | CO-197, CO-198 |
| N362 | Units exceed acceptable maximumCoverage & Eligibility | CO-151, CO-222 |
| N95 | Provider type can't bill this serviceCoverage & Eligibility | CO-8, CO-170, CO-B7 |
| N115 | Denied per Local Coverage DeterminationCoverage & Eligibility | CO-50, CO-167 |
| N386 | Denied per National Coverage DeterminationCoverage & Eligibility | CO-50, CO-96 |
| N674 | Missing prerequisite serviceCoverage & Eligibility | CO-50, CO-197 |
| N702 | Decision based on prior claim historyCoverage & Eligibility | CO-18, CO-B13 |
| MA04 | Secondary claim needs primary payer infoCOB & Secondary | CO-16, OA-23 |
| N4 | Missing prior insurer EOBCOB & Secondary | CO-16, CO-22 |
| N479 | Missing EOB for COB or MSPCOB & Secondary | CO-16, CO-22, OA-23 |
| N598 | Other health coverage is primaryCOB & Secondary | CO-22, PR-22 |
| N522 | Duplicate of a crossover claimCOB & Secondary | CO-18, OA-18 |
| MA92 | Missing other-insurance plan informationCOB & Secondary | CO-16, CO-22 |
| M25 | Documentation doesn't support level of serviceDocumentation & Medical Necessity | CO-150, CO-50 |
| M127 | Missing patient medical recordDocumentation & Medical Necessity | CO-16, CO-252 |
| N706 | Missing documentationDocumentation & Medical Necessity | CO-252, CO-16 |
| N179 | Information requested from the memberDocumentation & Medical Necessity | CO-227, PR-227 |
| N265 | Ordering provider identifier missing/invalidProvider Identifiers | CO-16, CO-183 |
| N286 | Referring provider identifier missing/invalidProvider Identifiers | CO-16, CO-183 |
| N290 | Rendering provider identifier missing/invalidProvider Identifiers | CO-16, CO-B7 |
| MA97 | Demo/clinical trial number missing or invalidProvider Identifiers | CO-16 |
| N418 | Misrouted claim — wrong payer address/systemProvider Identifiers | CO-109 |
| MA01 | Alert: appeal rights — 120 days (Medicare redetermination)Alerts & Appeals | — |
| MA02 | Alert: appeal rights — 180 daysAlerts & Appeals | — |
| MA13 | Alert: don't balance-bill non-PR amountsAlerts & Appeals | — |
| MA18 | Alert: claim crossed over to supplemental insurerAlerts & Appeals | — |
| N59 | Alert: see the provider manualAlerts & Appeals | — |
| N700 | Payment adjusted per EHR incentive programAlerts & Appeals | CO-237 |