CO-138
What This Code Means
Appeal procedures not followed or time limits not met. This code was deactivated by X12 (as of 05/01/2018).
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.
Educational reference only — not medical or legal advice. Always confirm code usage and appeal rights with the specific payer.