CO-45 Denial Code Explained

CO-17 denial code indicates the claim was denied because the procedure or service requires additional information, clarification, or documentation before reimbursement can be approved.

What Does CO-45 Mean?

Charge exceeds fee schedule, maximum allowable amount, or contracted/legislated fee arrangement.

This denial code indicates that the payer has reduced the amount paid because the provider's billed charge exceeds the allowable amount established by the payer contract, fee schedule, or reimbursement policy.

CO-45 is common with Medicare, Medicaid, and commercial insurance plans and does not necessarily mean the claim was processed incorrectly.

Why Did I Receive CO-45?

Common reasons include:

• The billed charge exceeds the contracted reimbursement rate.

• The payer applies a fee schedule adjustment.

• The service is subject to a maximum allowable amount.

• Contracted rates differ from the provider's standard charges.

• Medicare or commercial payer fee reductions apply.

In many cases, CO-45 is considered a contractual adjustment rather than a denial requiring correction.

How To Resolve CO-45

Review the Explanation of Benefits (EOB)

Verify the amount billed, the amount allowed, and the contractual adjustment applied by the payer.

Check Your Provider Contract

Compare the reimbursement amount against the payer's fee schedule or provider agreement.

Verify Allowed Charges

Confirm the billed CPT code matches the service performed and that the expected reimbursement aligns with payer guidelines.

For office visit services, review related CPT codes:

• CPT 99213

• CPT 99214

• CPT 99215

Appeal If Necessary

If the reimbursement appears inconsistent with the provider contract, submit a reconsideration request with supporting documentation.

Example of a CO-45 Denial

A provider bills $250 for an established patient office visit.

The insurance carrier's contracted allowable amount for the service is $165.

The payer processes the claim and applies a CO-45 adjustment for the difference between the billed amount and the allowable amount.

Result:

• Billed Amount: $250

• Allowed Amount: $165

• CO-45 Adjustment: $85

Related CPT Codes

CO-45 adjustments are frequently seen with:

• CPT 99213

• CPT 99214

• CPT 99215

• CPT 99203

• CPT 99204

Learn more at CPTCodeGuide.com.

Related Modifiers

While CO-45 is typically a reimbursement adjustment, these modifiers may affect claim processing:

• Modifier 25

• Modifier 59

• Modifier 26

• Modifier TC

Learn more at ModifierLookup.com.

Frequently Asked Questions

Is CO-45 a denial?

Not always. CO-45 often represents a contractual adjustment where the payer reduces payment to the allowable amount.

Can I bill the patient for a CO-45 adjustment?

Generally no. Contractual adjustments are typically written off according to payer agreements.

Should I appeal a CO-45 denial?

Only if the reimbursement amount appears inconsistent with the payer contract or fee schedule.

Is CO-45 common with Medicare?

Yes. Medicare frequently applies CO-45 adjustments when billed charges exceed the Medicare allowable amount.

Related Denial Codes

• CO-16 Missing Information

• CO-29 Timely Filing

• CO-97 Service Included in Another Service

• CO-109 Claim Not Covered by This Payer

• CO-22 Coordination of Benefits