What CO-45 means
The difference between your charge and the allowed amount. For in-network providers this is a normal contractual write-off, not a denial.
The CO group code means this amount is a contractual obligation: under most contracts you cannot bill it to the patient.
Common causes
- Billed charge higher than the contracted rate
How to fix it
- Write off the contractual adjustment
- Compare the allowed amount to your contract to catch underpayments
Check the remark code (RARC) that came with the denial and the payer's own policy, since rules vary by payer and plan. This is a plain-English summary written by GetMax; the official code text is published by X12 at x12.org/codes.
Prevent it next time
Most denials are caused before the claim is sent. See 12 ways to reduce claim denials, or let our denial management team work them for you.