J21Header code — not billable

Acute bronchiolitis

Chapter
10. Diseases of the respiratory system
Category
J21
Effective date
October 1, 2026

Related codes in category J21

J21.0Acute bronchiolitis due to respiratory syncytial virusYesJ21.1Acute bronchiolitis due to human metapneumovirusYesJ21.8Acute bronchiolitis due to other specified organismsYesJ21.9Acute bronchiolitis, unspecifiedYes

Frequently asked questions

What is ICD-10 code J21?

J21 is an ICD-10-CM diagnosis code for Acute bronchiolitis.

Is J21 a billable code?

No. J21 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 J21 in?

J21 falls under Chapter 10: Diseases of the respiratory system.

When did J21 become effective?

J21 has been effective since October 1, 2026, per the CMS/CDC ICD-10-CM annual release.

What other codes are related to J21?

J21 belongs to category J21, which includes 4 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.