J21 Acute bronchiolitis

The ICD-10-CM code for Acute bronchiolitis is J21 (FY2026). It is a non-billable category code — select a more specific code below for claims.

Classification

Chapter

10: Diseases of the respiratory system (J00-J99)

Section

J20-J22: Other acute lower respiratory infections (J20-J22)

Category J21

5 codes (4 billable)

FY2026 Status

Stable since FY2024

Official Coding Guidelines

COPD/asthma: acute exacerbation vs uncomplicated

a. Chronic Obstructive Pulmonary Disease [COPD] and Asthma 1) Acute exacerbation of chronic obstructive bronchitis and asthma The codes in categories J44 and J45 distinguish between uncomplicated cases and those in acute exacerbation. An acute exacerbation is a worsening or a decompensation of a chronic condition. An acute exacerbation is not equivalent to an infection superimposed on a chronic condition, though an exacerbation may be triggered by an infection.

Acute respiratory failure as principal diagnosis

b. Acute Respiratory Failure 1) Acute respiratory failure as principal diagnosis A code from subcategory J96.0, Acute respiratory failure, or subcategory J96.2, Acute and chronic respiratory failure, may be assigned as a principal diagnosis when it is the condition established after study to be chiefly responsible for occasioning the admission to the hospital, and the selection is supported by the Alphabetic Index and Tabular List. However, chapter- specific coding guidelines (such as obstetrics, poisoning, HIV, newborn) that provide sequencing direction take precedence.

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool

Cite This Page

Reference J21 with the canonical source and edition:

J21 — Acute bronchiolitis. ICD-10 Coding Pro (ICD-10-CM FY2026). https://icd10codingpro.com/codes/J21

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