CO-159 Denial Code: Service Resulted From Terrorism

What CO-159 means

CARC 159 reads “Service/procedure was provided as a result of terrorism.” It applies when the payer’s policy excludes injuries or illnesses caused by terrorist acts and the claim has been identified as terrorism-related.

This is one of the rarest adjustment codes. When it appears, the trigger is usually an external cause code in the Y38 category on the claim, a patient accident questionnaire, or records that describe the cause of injury.

Example: a patient treated for injuries from an attack has the Y38 external cause code on the claim. The payer’s policy contains a terrorism exclusion, and the claim returns CO-159.

Common causes

• External cause coding showing terrorism as the mechanism of injury in box 21.
• Accident information supplied by the patient that describes a terrorist event.
• Policy exclusions specific to terrorism in the patient’s coverage.
• Miscoding, where a terrorism external cause code was selected in error.

How to fix it

1. Verify the documentation. Make sure the record actually supports a terrorism-related cause before accepting the adjustment.
2. Correct coding errors with a corrected claim using resubmission code 7 in box 22.
3. Look for other responsible coverage. Workers’ compensation may apply for on-the-job injuries, and government victim programs sometimes exist after specific events. Their rules vary.
4. Request the exclusion language from the payer and appeal if the policy does not clearly apply.
5. Bill the patient only when the payer assigns patient responsibility and no other source applies.

How to prevent it

• Capture complete accident details at registration, including whether the injury occurred at work (box 10a).
• Code external causes accurately and only from clinical documentation.
• Route exclusion denials to a reviewer rather than rebilling automatically, since resubmitting the same claim will not change the outcome. Read more on why claims are denied versus rejected.
• Keep a short list of exclusion CARCs (157, 158, 159, 160) in your denial workflow so they go to someone who can check coverage, not to the resubmission queue.

Handling mass-casualty events

After a large event, many patients may present with related injuries at once. Coordinate registration so the same accident details are captured for every patient, confirm with major payers how they are handling claims from the event, and watch for public announcements about dedicated funding or claims programs. Payers sometimes issue guidance that changes how exclusions apply after a specific event, so check provider bulletins before accepting a CO-159 as final.