Quick Explanation
This denial code indicates that the insurance carrier has processed the claim but issued the reimbursement directly to the patient or policyholder rather than the provider. This typically happens when the provider is out-of-network, or when the Assignment of Benefits indicator is missing or incorrectly reported on the claim.
Common Causes for CO-100
Denials with code CO-100 typically happen for the following specific reasons:
- The 'Accept Assignment' indicator in Box 27 of the CMS-1500 claim form was checked 'No' or left blank.
- The provider is out-of-network, and the payer's policy dictates that all out-of-network reimbursements must be sent directly to the member.
- A signed Assignment of Benefits (AOB) form was not secured from the patient during the intake process.
- A processing error occurred on the payer's end, resulting in a failure to recognize the 'Yes' in the Accept Assignment field.
How to Prevent CO-100 Denials
To avoid receiving this denial in the future, implement these specific checks:
- Mandate that a signed Assignment of Benefits (AOB) form is collected and scanned into the EHR during patient registration.
- Configure the billing system to automatically populate Box 27 of the CMS-1500 form with 'Yes' for participating and applicable non-participating claims.
- Verify out-of-network payment policies during the insurance verification process to identify plans that pay patients directly.
- Establish a clear collection policy at the time of service for out-of-network patients whose insurance plans pay the member directly.
Appeal Letter Template for CO-100
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-100 - Payment made to patient/insured/responsible party/employer
Dear Appeals Department,
I am writing to appeal the denial of the above-referenced claim, which was denied with code CO-100: "Payment made to patient/insured/responsible party/employer".
We are appealing the direct-to-patient payment routing for claim [Claim Number] under denial code CO-100. A valid, signed Assignment of Benefits (AOB) was executed by the insured prior to the date of service, legally transferring the right to receive insurance payments directly to our facility. In accordance with standard healthcare billing regulations and CMS guidelines, the 'Accept Assignment' field (Box 27) was appropriately marked 'Yes' on the submitted CMS-1500 form. Therefore, the payer is contractually and legally obligated to remit payment directly to the provider of service. We have enclosed a copy of the executed AOB form and request that the payer immediately reprocess this claim and issue direct payment to our office, correcting this administrative misdirection.
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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