ICD-10-CM > V00-Y99 > Y90-Y99 > Y99 Y99 External cause status Non-Billable/Non-Specific Notes A single code from category Y99 should be used in conjunction with the external cause code(s) assigned to a record to indicate the status of the person at the time the event occurred. Codes Y99.0Civilian activity done for income or payY99.1Military activityY99.2Volunteer activityY99.8Other external cause statusY99.9Unspecified external cause status