CO-15 — Authorization number missing or invalid
Claim-adjustment reason code 15 · typically reported as CO-15
What it means
An authorization exists but the number on the claim is missing, malformed, or doesn’t match what the payer issued.
Why DME claims hit it
- PA number entered with typos or in the wrong claim field
- Auth issued under a different HCPCS or date span than what was billed
How to fix it
- Pull the actual auth letter; verify number, code, units, and date range
- Resubmit with the corrected auth number in the proper field (2300 REF*G1 on the 837)
Appeal posture
Usually a resubmission, not an appeal. If the auth itself was payer-error, appeal with the approval letter attached.
Related denial codes
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