Acute bronchiolitis (J21) ICD-10-CM
The J21 code range covers acute bronchiolitis with 5 ICD-10-CM diagnosis codes. 4 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Includes
This note appears immediately under a three character code title to further define, or give examples of, the content of the category.
- acute bronchiolitis with bronchospasm
Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
- respiratory bronchiolitis interstitial lung disease J84.115
Codes in the J21 Range 5 codes · 4 billable
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the J21 range.
Bronchioles
The small airways branching off the TERTIARY BRONCHI. Terminal bronchioles lead into several orders of respiratory bronchioles which in turn lead into alveolar ducts and then into PULMONARY ALVEOLI.
Bronchiolitis
Inflammation of the BRONCHIOLES.
Bronchiolitis Obliterans
Inflammation of the BRONCHIOLES leading to an obstructive lung disease. Bronchioles are characterized by fibrous granulation tissue with bronchial exudates in the lumens. Clinical features include a nonproductive cough and DYSPNEA.
Bronchiolitis Obliterans Syndrome
Bronchiolitis obliterans complication from allogenic HEMATOPOIETIC STEM CELL TRANSPLANTATION and LUNG TRANSPLANTATION.
Bronchiolitis, Viral
An acute inflammatory disease of the lower RESPIRATORY TRACT, caused by paramyxoviruses, occurring primarily in infants and young children; the viruses most commonly implicated are PARAINFLUENZA VIRUS TYPE 3; RESPIRATORY SYNCYTIAL VIRUS, HUMAN; and METAPNEUMOVIRUS.
Cryptogenic Organizing Pneumonia
An interstitial lung disease of unknown etiology, occurring between 21-80 years of age. It is characterized by a dramatic onset of a pneumonia-like illness with cough, fever, malaise, fatigue, and weight loss. Pathological features include prominent interstitial inflammation without collagen fibrosis, diffuse fibroblastic foci, and no microscopic honeycomb change. There is excessive proliferation of granulation tissue within small airways and alveolar ducts.
About the J21 Code Range
Acute bronchiolitis, classified under the ICD-10 code J21, refers to a sudden inflammation of the small airways in the lungs. These codes cover cases caused by specific viruses and those where the cause is not specified, helping healthcare professionals accurately identify and document the condition.
The ICD-10 code for acute bronchiolitis includes subcategories that specify the causing agent. For example, J21.0 is used when the inflammation is due to respiratory syncytial virus (RSV), commonly known by terms like "acute viral bronchiolitis" or "respiratory syncytial virus bronchiolitis." Similarly, J21.1 applies to bronchiolitis caused by human metapneumovirus, sometimes referred to as "human metapneumovirus infection." The code J21.8 represents cases caused by other specified organisms, such as adenovirus-related bronchiolitis. In situations where no specific cause is identified, J21.9 captures unspecified acute bronchiolitis, encompassing conditions like "acute bronchiolitis with bronchospasm" or "acute exudative bronchiolitis." These codes assist in precise clinical documentation, treatment decisions, and accurate health record management related to viral and other infectious causes of acute bronchiolitis.
Questions About This Page
How many billable codes are in the J21 range?
Of the 5 codes in this range, 4 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the J21 range classify?
The range classifies acute bronchiolitis. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
