Home Denial Codes CO-128
Denial Code CO-128

Copayment amount (Updated for 2026)

Copayment amount

Quick Explanation

Denial code CO-128 indicates that a specific portion of the billed amount has been designated as the patient's copayment responsibility under their insurance plan. This is an adjudication decision shifting the financial liability of that specific dollar amount from the insurance carrier to the patient, rather than an outright rejection of the service itself.

Common Causes for CO-128

Denials with code CO-128 typically happen for the following specific reasons:

How to Prevent CO-128 Denials

To avoid receiving this denial in the future, implement these specific checks:

Appeal Letter Template for CO-128

If you believe this claim was denied incorrectly, you can use the following template to submit an appeal.

[Your Practice Header]
[Date]

[Payer Name]
[Appeals Department Address]

RE: Appeal for Claim [Claim Number]
Patient: [Patient Name]
ID: [Patient ID]
Date of Service: [Date]
Denial Code: CO-128 - Copayment amount

Dear Appeals Department,

I am writing to appeal the denial of the above-referenced claim, which was denied with code CO-128: "Copayment amount".

We are appealing the application of the copayment amount under code CO-128 for the services rendered on the specified date of service. Under the Affordable Care Act (ACA) and CMS guidelines, preventive services with a Grade A or B recommendation from the USPSTF must be covered at 100% with no patient cost-sharing, including copayments. The billed service on this claim is an eligible preventive procedure and should not have been subjected to a copayment deduction. We respectfully request that you review the clinical documentation, re-adjudicate this claim in accordance with federal preventive service mandates, and issue the remaining contractually allowed payment to the provider.

Attached please find:
1. A copy of the original claim.
2. The relevant medical records supporting the service.
3. [Any other supporting documents].

We respectfully request that you reprocess this claim for payment.

Sincerely,

[Your Name]
[Title]
[Practice Name]
            

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