OA-157: Service Denied — Provided Due to Act of War

What Does OA-157 Mean?

OA-157 is uncommon and may appear when the act-of-war adjustment is informational rather than contractual. The resolution is the same — check for coding errors, correct if needed, or appeal with documentation.

CARC 157 is a rare and highly specific denial code that appears when the payer has determined the service or procedure was provided as a result of an act of war. Nearly all standard health insurance plans include an act-of-war exclusion clause that allows the insurer to deny coverage for medical services resulting from war, military action, or armed conflict.

In practice, this denial is uncommon in domestic civilian billing. When it does appear, the most frequent cause is a coding error — a billing staff member inadvertently used a code, modifier, or external cause code that indicated the service was related to an act of war when it was not. The second scenario is payer misinterpretation, where the diagnosis codes, location information, or circumstances documented in the claim led the payer to incorrectly conclude the service was war-related. Less commonly, the denial correctly applies to a civilian health plan when the patient received care for injuries genuinely caused by a war-related event.

The critical first step is determining whether the denial is correct. If it is a coding error, the fix is straightforward — correct the codes and resubmit. If the payer misinterpreted the circumstances, an appeal with documentation proving the service was not war-related should resolve it. If the service was genuinely provided due to an act of war and the patient has military or government coverage (TRICARE, VA benefits, Defense Health Agency), those programs may provide coverage that civilian plans do not.

How to Resolve

Determine whether the denial was triggered by a coding error, payer misinterpretation, or an actual act-of-war situation, then take the appropriate corrective action.

1. Review the denial details Check the ERA and RARC codes for specific information about the war-related determination.
2. Follow the CO-157 resolution process Check for coding errors, correct and resubmit if applicable, or appeal with documentation.

How to Prevent OA-157

• Follow the same coding review and documentation practices as for CO-157 denials

Also Filed As

The same CARC 157 may appear with different Group Codes:

Related Denial Codes