J21
ICD-10Non-billable categoryAcute bronchiolitis
Official ICD-10-CM descriptor (FY2026)
Acute bronchiolitis
J21 is a category heading, not a billable code. CMS does not accept it on a claim; report one of the more specific codes beneath it.
Includes
- acute bronchiolitis with bronchospasm
Excludes2
Not included here. The condition is not part of this code, but a patient may have both, and both codes may be reported together.
- respiratory bronchiolitis interstitial lung disease (J84.115)
More specific codes under J21
Where this code sits
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ICD-10-CM FY2026. Centers for Medicare & Medicaid Services (CMS) / National Center for Health Statistics (NCHS), “2026 ICD-10-CM Code Descriptions in Tabular Order” (icd10cm_order_2026.txt). Download the original file from cms.gov. Public domain (US Government work). Descriptors, billable flags and instructional notes on this page are reproduced from that file without modification. Krasyn adds no clinical guidance.