J21 – Acute bronchiolitis
ICD-10-CM 2027 diagnosis code · Other acute lower respiratory infections
ICD-10-CM code
J21
- Code
J21(claims format:J21)- Description
- Acute bronchiolitis
- Billable
- No – use a more specific code below
- Valid for
- Dates of service October 1, 2026 – September 30, 2027 (FY2027)
- Chapter
- 10. Diseases of the respiratory system (J00-J99)
- Block
- J20-J22 Other acute lower respiratory infections
Billable codes under J21
J21 is a header code and cannot be used on claims. Choose the most specific code:
Notes for J21
Includes:
- acute bronchiolitis with bronchospasm
Excludes2 (not included here):
- respiratory bronchiolitis interstitial lung disease (J84.115)
Notes inherited from parent codes
Instructional notes at a category or block level apply to every code below it.
Block J20-J22
Excludes2 (not included here):
- chronic obstructive pulmonary disease with acute lower respiratory infection (J44.0)
Frequently asked questions
What is ICD-10 code J21?
J21 is the ICD-10-CM code for acute bronchiolitis, in the block J20-J22 (Other acute lower respiratory infections).
Is J21 a billable code?
No. J21 is a header code with more specific child codes; report one of the billable codes listed above.
Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.