| M12 | Diagnostic Tests Missing Purchased Service Indicator | Supplemental | → |
| M15 | Separately Billed Services Combined Into One Procedure | Supplemental | → |
| M20 | Missing or Invalid HCPCS Procedure Code | Supplemental | → |
| M27 | Provider Liable for Waived Patient Charges | Informational | → |
| M30 | Missing or Invalid Patient Liability Amount | Supplemental | → |
| M32 | Missing or Invalid Occurrence Code or Date | Supplemental | → |
| M36 | Missing or Incomplete Claim Information for This Service | Supplemental | → |
| M38 | Missing or Invalid Referring Provider Information | Supplemental | → |
| M39 | Missing or Invalid Date of Service or Admission Date | Supplemental | → |
| M49 | Missing or Invalid Value Codes or Amounts | Supplemental | → |
| M50 | Missing or Invalid Revenue Code | Supplemental | → |
| M51 | Missing or Invalid Procedure Code | Supplemental | → |
| M55 | Missing or Invalid Claim Type or Bill Type | Supplemental | → |
| M60 | Missing or Invalid Certificate of Medical Necessity | Supplemental | → |
| M62 | Missing or Invalid Attending Provider Information | Supplemental | → |
| M76 | Missing or Invalid Diagnosis or Condition | Supplemental | → |
| M77 | Missing or Invalid Place of Service | Supplemental | → |
| M80 | Service Not Covered When Performed in This Setting | Supplemental | → |
| M86 | Duplicate or Similar Service Already Paid | Supplemental | → |
| M114 | Missing or Invalid Information on Ordering or Referring Provider | Supplemental | → |
| M117 | Service Not Payable Per Managed Care Contract | Supplemental | → |
| M119 | Missing or Invalid NDC Code for Drug Claim | Supplemental | → |
| M124 | Missing Equipment Ownership Declaration for Part or Supply | Supplemental | → |
| MA01 | Appeal Rights Notice for Denied Services | Informational | → |
| MA04 | Primary Payer Information Missing for Secondary Claim | Supplemental | → |
| MA18 | Claim Received and Assigned for Processing | Informational | → |
| MA61 | Missing or Inaccurate Information on Claim | Supplemental | → |
| MA63 | Missing or Invalid Principal Diagnosis Code | Supplemental | → |
| MA66 | Missing or Invalid Principal Procedure Code | Supplemental | → |
| MA120 | Missing or Invalid CLIA Certification Number | Supplemental | → |
| MA130 | Unprocessable Claim with No Appeal Rights | Supplemental | → |
| N4 | Missing or Invalid Prior Payer EOB | Supplemental | → |
| N19 | Procedure Considered Incidental to Primary Service | Supplemental | → |
| N20 | Service Not Payable on Same Date as Another | Supplemental | → |
| N30 | Patient Not Eligible for This Service | Supplemental | → |
| N54 | Claim Does Not Match Prior Authorization Details | Supplemental | → |
| N56 | Procedure Code Invalid for Service or Date | Supplemental | → |
| N95 | Provider Type or Specialty Cannot Bill Service | Supplemental | → |
| N104 | Claim Sent to Wrong Medicare Jurisdiction | Supplemental | → |
| N115 | Decision Based on Local Coverage Determination (LCD) | Supplemental | → |
| N120 | Home Health Partial Episode Payment Adjustment | Supplemental | → |
| N127 | Resubmit Claim to UMWA Health Plan | Supplemental | → |
| N130 | Check Plan Benefits for Service Restrictions | Supplemental | → |
| N180 | Service Does Not Meet Billed Category Criteria | Supplemental | → |
| N264 | Missing or Invalid Ordering Provider Name | Supplemental | → |
| N286 | Missing or Invalid Referring Provider Identifier | Supplemental | → |
| N290 | Missing or Invalid Rendering Provider Identifier | Supplemental | → |
| N321 | Missing or Invalid Last Admission Period | Supplemental | → |
| N350 | Missing Description for Unlisted or NOC Code | Supplemental | → |
| N362 | Days or Units Exceed Acceptable Maximum | Supplemental | → |
| N372 | Only Reasonable and Necessary Maintenance Charges Covered | Supplemental | → |
| N381 | Refer to Contract for Payment Restrictions | Informational | → |
| N386 | Decision Based on National Coverage Determination | Supplemental | → |
| N390 | Service Cannot Be Billed Separately | Supplemental | → |
| N428 | Service Not Covered at This Place of Service | Supplemental | → |
| N430 | Procedure Code Does Not Match Units Billed | Supplemental | → |
| N432 | Alert: Adjustment Based on Recovery Audit | Informational | → |
| N448 | Service Not on Fee Schedule or Contract | Supplemental | → |
| N479 | Missing EOB for COB or MSP Claim | Supplemental | → |
| N517 | Resubmit a New Claim With the Requested Information | Supplemental | → |
| N519 | Invalid Combination of HCPCS Modifiers | Supplemental | → |
| N522 | Duplicate of a Previously Processed Claim | Supplemental | → |
| N525 | Service Not Covered During Global Period | Supplemental | → |
| N527 | Claim Processed as Primary Before Recovery Demand | Supplemental | → |
| N570 | Missing or Invalid Provider Credentialing Data | Supplemental | → |
| N572 | Non-Payable Reporting Codes or Modifiers Required | Supplemental | → |
| N574 | Ordering/Referring Provider Type Cannot Order or Refer | Supplemental | → |
| N575 | Ordering/Referring Provider Name Mismatch on File | Supplemental | → |
| N576 | Services Not Related to Reported Incident or Claim | Supplemental | → |
| N585 | Benefits Ended Due to Final Injury Settlement | Supplemental | → |
| N587 | Insurance Policy Benefits Fully Exhausted | Supplemental | → |
| N588 | Patient Directed Claims Not Be Processed | Supplemental | → |
| N590 | Independent Medical Exam Report Missing | Supplemental | → |
| N591 | Payment Adjusted After IME or Utilization Review | Supplemental | → |
| N657 | Services Must Use Correct Procedural Code | Supplemental | → |
| N669 | Payment Adjusted Per Medicare Fee Schedule | Supplemental | → |
| N699 | Payment Adjusted Under PQRS Incentive Program | Supplemental | → |
| N710 | Required Clinical Notes or Documentation Missing | Supplemental | → |
| N712 | Required Summary Document Missing from Claim | Supplemental | → |
| N714 | Required Report Missing from Claim Submission | Supplemental | → |
| N716 | Patient Medical Chart Missing from Claim | Supplemental | → |
| N763 | Demonstration Code Not Appropriate for Claim | Supplemental | → |
| N770 | Provider Adjustment Request Has Been Processed | Supplemental | → |
| N781 | No Deductible Allowed for QMB Patient | Informational | → |
| N830 | Processed Under Balance Billing / No Surprises Rules | Informational | → |
| N831 | Provider Enrollment Revalidation Request Unanswered | Supplemental | → |
| N898 | Medicare Drug Price Negotiation Program Adjustment | Supplemental | → |
| N927 | Missing, Incomplete, or Invalid X-Ray | Supplemental | → |
| N935 | Patient No Longer a Medicaid or Qualified Medicare Beneficiary | Informational | → |
| N936 | Service Subject to Multiple Procedure Payment Reduction (MPPR) | Supplemental | → |
| N938 | Do Not Resubmit — Claim Will Be Automatically Reprocessed | Informational | → |
| N939 | Peer-to-Peer Review Available | Informational | → |