M33
What This Code Means
The claim is missing, incomplete, or has an invalid UPIN for the ordering/referring/performing provider. This code was deactivated by X12 (as of 08/01/2004). See: M68.
How to Resolve or Appeal
- This is a historical/deactivated code — no longer used on current claims. If seen on an old remittance, refer to the replacement code noted above where available.
More Denial Codes to Check
Educational reference only — not medical or legal advice. Always confirm code usage and appeal rights with the specific payer.