Healthcare Error Code
Healthcare Insurance / Medical Billing
Common CMS / Medicare Issues
M184 | Incorrect patient
Industry
Healthcare
Canonical
/healthcare/error-codes/m184/
Last Updated
Feb 25, 2026
Summary
This code indicates that the patient information on the claim does not match payer records.
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What This Code Means
M184 is applied when the payer cannot validate the patient identified on the claim. This reflects an identification or data matching issue rather than a coverage determination. The service may be covered once patient information is corrected. The code does not imply that the service itself is invalid. Accurate patient identification is required for adjudication.
Where Users Usually See This Code
- Medicare remittance advice
- Claim rejection notices
- Patient validation reports
Why This Code Appears
- Patient identifiers do not match records
- Incorrect demographic information submitted
- Enrollment data discrepancies
What Typically Happens Next
- Claim processing is halted or denied
- Reprocessing may be required
- Payment is delayed
What This Code Is Not
- It is not a coverage exclusion
- It is not patient responsibility
- It is not a contractual adjustment
Troubleshooting Checklist
- □ Verify patient identifiers
- □ Confirm demographic accuracy
- □ Monitor claim status
Notes And Edge Cases
Recent enrollment updates may not yet be reflected. Minor data differences can affect patient matching.
Related Codes
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