CO-45: Charge Exceeds Fee Schedule or Maximum Allowable
CO (Contractual Obligation)What is CO-45?
CO-45 is a Contractual Obligation adjustment indicating the billed charge exceeds the payer's fee schedule, maximum allowable amount, or contracted rate. This is the most common CARC code across all payers and typically represents a contractual write-off, not a true denial.
Why Does CO-45 Occur?
- Billed amount exceeds contracted rate. The provider's charge master is set higher than the payer's allowed amount, which is standard practice.
- Out-of-network rate applied. The payer applies a lower OON allowable instead of the contracted in-network rate.
- Fee schedule update not reflected. The payer updated their fee schedule but the adjustment was not communicated or applied correctly.
- Incorrect place of service affecting rate. Different places of service (office vs. facility) have different fee schedules.
How to Fix CO-45 Denials
- Compare the allowed amount on the EOB to your contracted rate for the procedure code. If they match, CO-45 is a standard write-off and no action is needed.
- If the allowed amount is lower than your contracted rate, pull the contract and verify the fee schedule for that CPT code and place of service.
- Check if the claim processed as in-network or out-of-network. Incorrect network status is a common cause of underpayment.
- If the payment is wrong, file a dispute or reconsideration with the contract terms attached. Most payers allow 60-365 days.
CO-45 by Payer
| Payer | Common RARC | Appeal Deadline | Notes |
|---|---|---|---|
| UnitedHealthcare | N/A | 60 days from remittance | CO-45 is standard for contracted rate adjustments. Verify network status if underpaid. |
| Anthem | N/A | 365 days from denial notice | Fee schedules vary by state. Check your state-specific contract. |
| Aetna | N/A | 180 days from denial | Compare against Aetna's fee schedule lookup tool for your specialty. |
| Cigna | N/A | 180 days from denial | Cigna may apply geographic adjustments. Check GPCI-based rates. |
| Medicare | N/A | 120 days (redetermination at MAC) | Medicare Physician Fee Schedule (MPFS) is the definitive source. Updated annually. |
Related CARC Codes
If you are seeing CO-45, check these related codes: CO-50 (non-covered service), PR-1 (deductible not met), PR-2 (coinsurance).
Common Questions About CO-45
Is CO-45 a denial?
Not usually. CO-45 is a contractual adjustment, meaning the payer reduced the charge to the contracted allowed amount. This is standard for in-network claims and represents a write-off, not a denial requiring appeal.
When should I appeal a CO-45?
Appeal when the allowed amount is lower than your contracted rate, or when the claim processed as out-of-network incorrectly. Attach the relevant contract terms.
Altair catches CO-45 denials before submission with fee schedule verification. See how pre-submit claim scoring works.