Y99: External cause status
Codes under Y99 (External cause status). A ✓ marks a billable (fully specified) code; category codes without a ✓ are not billable on their own.
| Code | Description | Billable |
|---|---|---|
| Y99.0 | Civilian activity done for income or pay | ✓ |
| Y99.0 | Civilian activity done for income or pay | ✓ |
| Y99.1 | Military activity | ✓ |
| Y99.1 | Military activity | ✓ |
| Y99.2 | Volunteer activity | ✓ |
| Y99.2 | Volunteer activity | ✓ |
| Y99.8 | Other external cause status | ✓ |
| Y99.8 | Other external cause status | ✓ |
| Y99.9 | Unspecified external cause status | ✓ |
| Y99.9 | Unspecified external cause status | ✓ |
Frequently asked questions
What is ICD-10-CM code Y99?
Y99 is an ICD-10-CM category covering External cause status. It contains 10 more specific diagnosis codes, 10 of which are billable.
Is Y99 a billable code?
No — Y99 is a category header and isn't billable on its own. Code to the highest level of specificity using one of its subcodes (for example Y99.0 — Civilian activity done for income or pay). 10 of the 10 codes under Y99 are billable.
What codes fall under Y99?
Y99 includes Y99.0, Y99.0, Y99.1, Y99.1, Y99.2, plus 5 more. See the full list with descriptions and billable status above.
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Informational only, not coding or medical advice. Verify against the official ICD-10-CM (FY2026) and your payer's guidelines.
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