J21.9 Acute bronchiolitis, unspecified

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applicable to

• Bronchiolitis (acute)

Excludes1 (never code together)

• chronic bronchiolitis (J44.89)

Applies from J21 Acute bronchiolitis

Includes

• acute bronchiolitis with bronchospasm

Excludes2 (not included here)

• respiratory bronchiolitis interstitial lung disease (J84.115)

MS-DRG index

Defines the logic of DRG(s) 202-203 in MDC 04.

Approximate ICD-9-CM (GEMs)

• 466.19 Acute bronchiolitis due to other infectious organisms (approximate)

Code annotations containing back-references to J21.9

Back-references to J21

• Code Also: D81.82 Activated Phosphoinositide 3-kinase Delta Syndrome [APDS] ("other acute respiratory tract infections (J00-J06; J20-J22)")
• Type 2 Excludes: J18.0 Bronchopneumonia, unspecified organism ("acute bronchiolitis (J21.-)")
• Type 1 Excludes: J98.01 Acute bronchospasm ("acute bronchiolitis with bronchospasm (J21.-)")

Diagnosis Index entries for J21.9

• Bronchiolitis (acute) (infective) (subacute)
• Bronchiolitis (acute) (infective) (subacute) › with › bronchospasm or obstruction
• Bronchospasm (acute) › with › bronchiolitis, acute

Nearby codes

• J21 Acute bronchiolitis
• J21.0 Acute bronchiolitis due to respiratory syncytial virus
• J21.1 Acute bronchiolitis due to human metapneumovirus
• J21.8 Acute bronchiolitis due to other specified organisms
• J21.9 Acute bronchiolitis, unspecified (this code)