Y99 External cause status
The ICD-10-CM code for External cause status is Y99 (FY2026). It is a non-billable category code — select a more specific code below for claims.
Classification
- Section
- Y90-Y99: Supplementary factors related to causes of morbidity classified elsewhere (Y90-Y99)
- Category Y99
- 6 codes (5 billable)
- FY2026 Status
- Stable since FY2024
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.
Official Coding Guidelines
External cause codes not first-listed/principal20. Chapter 20: External Causes of Morbidity (V00-Y99) The external causes of morbidity codes should never be sequenced as the first-listed or principal diagnosis.
Assign Y99 with other external cause codes; indicates work/statusk. External Cause Status A code from category Y99, External cause status, should be assigned whenever any other external cause code is assigned for an encounter, including an Activity code, except for the events noted below. Assign a code from category Y99, External cause status, to indicate the work status of the person at the time the event occurred. The status code indicates whether the event occurred during military activity, whether a non-military person was at work, whether an individual including a student or volunteer was involved in a non-work activity at the time of the causal event.
Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026