Home Denial Codes CO-104
Denial Code CO-104

Services not covered under Medicare+Choice plans (Updated for 2026)

Services not covered under Medicare+Choice plans

Quick Explanation

Denial code CO-104 indicates that the billed services are not covered under the patient's Medicare Advantage (formerly Medicare+Choice) plan. This typically occurs when a service is explicitly excluded by the managed care plan or must be billed directly to Original Medicare (Fee-for-Service) due to specific CMS carve-out regulations, such as hospice care or clinical trial services.

Common Causes for CO-104

Denials with code CO-104 typically happen for the following specific reasons:

How to Prevent CO-104 Denials

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

Appeal Letter Template for CO-104

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-104 - Services not covered under Medicare+Choice plans

Dear Appeals Department,

I am writing to appeal the denial of the above-referenced claim, which was denied with code CO-104: "Services not covered under Medicare+Choice plans".

We are appealing the denial of this claim under denial code CO-104. While the patient is enrolled in a Medicare Advantage plan, the services rendered on the date of service are eligible for coverage and reimbursement. According to CMS billing guidelines and Chapter 4 of the Medicare Managed Care Manual, specific services—such as qualifying clinical trial costs or hospice care—are carve-outs that must be reimbursed, or the services meet the specific exception criteria under the plan's emergency service provisions. We have attached the medical documentation demonstrating that the services met all criteria for coverage, and we request a review and prompt processing of this claim for payment.

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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