Y99Header code — not billable

External cause status

Chapter
20. External causes of morbidity
Category
Y99
Effective date
October 1, 2026

Related codes in category Y99

Y99.0Civilian activity done for income or payYesY99.1Military activityYesY99.2Volunteer activityYesY99.8Other external cause statusYesY99.9Unspecified external cause statusYes

Frequently asked questions

What is ICD-10 code Y99?

Y99 is an ICD-10-CM diagnosis code for External cause status.

Is Y99 a billable code?

No. Y99 is a category/header code, not billable on its own — use one of its more specific child codes instead.

What ICD-10-CM chapter is Y99 in?

Y99 falls under Chapter 20: External causes of morbidity.

When did Y99 become effective?

Y99 has been effective since October 1, 2026, per the CMS/CDC ICD-10-CM annual release.

What other codes are related to Y99?

Y99 belongs to category Y99, which includes 5 other codes — see the related codes list on this page.

ICD-10-CM data maintained by CDC/CMS (public domain). Always verify codes with authoritative sources before making coding or billing decisions.