Home Denial Codes CO-157
Denial Code CO-157

Service was provided as a result of an act of war (Updated for 2026)

Service was provided as a result of an act of war

Quick Explanation

Denial code CO-157 indicates that the insurance payer has denied the claim because they determined the services rendered were to treat an illness or injury resulting from an act of war, which is a standard exclusion in most commercial health insurance policies. This denial typically occurs when external cause codes or medical documentation mistakenly suggest the patient's condition was due to military conflict, terrorism, or civil unrest.

Common Causes for CO-157

Denials with code CO-157 typically happen for the following specific reasons:

How to Prevent CO-157 Denials

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

Appeal Letter Template for CO-157

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-157 - Service was provided as a result of an act of war

Dear Appeals Department,

I am writing to appeal the denial of the above-referenced claim, which was denied with code CO-157: "Service was provided as a result of an act of war".

We are formally appealing the denial of this claim under code CO-157. The medical records attached clearly demonstrate that the patient's treated condition or injury was the result of a standard civilian incident and was entirely unrelated to any act of war, military conflict, or civil insurrection. No ICD-10-CM codes indicating operations of war (Y36) or military operations (Y37) were utilized, and the documentation does not support the exclusion of these services under the policy's war clause. In accordance with AMA CPT and CMS guidelines for covered civilian medical care, we request that this claim be re-evaluated and processed for immediate 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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