Authorization number missing, invalid or does not apply
An authorization exists, but the number on the claim is missing or wrong, or it does not cover this service, date or provider.
CO = Contractual Obligation. The provider owes the difference. The patient cannot be billed for this amount. The same reason code can appear with a different group code; the group decides who may be billed.
Usual causes
- Authorization number left off the claim (loop 2300 REF G1, box 23).
- Typo in the number.
- Authorization issued for a different code, date range, number of units or rendering provider.
The fix
Pull the authorization letter. Enter the exact number and make sure the code, dates, units and provider match it. Send a corrected claim. If the service changed from what was authorized, ask the payer for an updated authorization before resubmitting.
Appeal or corrected claim?
Corrected claim when the number was missing or wrong. If the authorization does not match the service, you may need a retro-authorization request or an appeal with the clinical reason for the change.
Deadline to watch
Timely filing limit; many payers allow retro-authorization requests only within 2 to 30 days of the service.
Exact limits are in your payer contract or provider manual. When in doubt, send the correction or appeal this week.
CO-15 in short
What does CO-15 mean?
An authorization exists, but the number on the claim is missing or wrong, or it does not cover this service, date or provider. The official X12 text reads: "The authorization number is missing, invalid, or does not apply to the billed services or provider."
What usually causes a CO-15 denial?
Authorization number left off the claim (loop 2300 REF G1, box 23). Typo in the number. Authorization issued for a different code, date range, number of units or rendering provider.
How do I fix CO-15?
Pull the authorization letter. Enter the exact number and make sure the code, dates, units and provider match it. Send a corrected claim. If the service changed from what was authorized, ask the payer for an updated authorization before resubmitting.
Should I appeal CO-15 or send a corrected claim?
Corrected claim. Corrected claim when the number was missing or wrong. If the authorization does not match the service, you may need a retro-authorization request or an appeal with the clinical reason for the change.
What deadline applies to CO-15?
Timely filing limit; many payers allow retro-authorization requests only within 2 to 30 days of the service.