2027 ICD-10-CM Diagnosis Code J21Acute bronchiolitis

ICD-10-CM Codes›J00–J99›J20-J22›J21

ICD-10-CM J21
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

J21 is a non-billable ICD-10-CM category code for acute bronchiolitis, so it cannot be submitted on claims. Use a more specific code from this category instead, such as J21.0, J21.1, J21.8, and J21.9.

Code Identity

ICD-10-CM Code
J21
Billable Status
No — Non-Billable Category
Code Describes
Acute bronchiolitis
Short Description
Acute bronchiolitis
Same as the full description in the CMS dataset.
Chapter
J20-J22
Other acute lower respiratory infections

Code Classification

ChapterJ00–J99Diseases of the respiratory system
SectionJ20-J22Other acute lower respiratory infections
CategoryJ21Acute bronchiolitis
This CodeJ21Acute bronchiolitis

Specific Coding for Acute bronchiolitisOverview

Non-specific codes like J21 require more characters. Use one of these billable codes instead:

  • Use J21.0 for Acute bronchiolitis due to respiratory syncytial virus

  • Use J21.1 for Acute bronchiolitis due to human metapneumovirus

  • Use J21.8 for Acute bronchiolitis due to other specified organisms

  • Use J21.9 for Acute bronchiolitis, unspecified

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to J21: its own notes plus those printed at block J20-J22 and Chapter 10. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

  • acute bronchiolitis with bronchospasm

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

On J21 itself
  • respiratory bronchiolitis interstitial lung disease (J84.115)
From Block J20-J22 Other acute lower respiratory infections applies to 15 codes
  • chronic obstructive pulmonary disease with acute lower respiratory infection (J44.0)
From Chapter 10 (J00-J99) Diseases of the respiratory system applies to 366 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • smoke inhalation (T59.81-)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 10 (J00-J99) Diseases of the respiratory system applies to 366 codes
  • code, where applicable, to identify:
  • exposure to environmental tobacco smoke (Z77.22)
  • exposure to tobacco smoke in the perinatal period (P96.81)
  • history of tobacco dependence (Z87.891)
  • occupational exposure to environmental tobacco smoke (Z57.31)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)

Notes

General instructions on how these codes are used.

From Chapter 10 (J00-J99) Diseases of the respiratory system applies to 366 codes
  • When a respiratory condition is described as occurring in more than one site and is not specifically indexed, it should be classified to the lower anatomic site (e.g. tracheobronchitis to bronchitis in J40).

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name J21, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming J21: they are not reported together with it, unless the two conditions are unrelated.

  • J98.01 Acute bronchospasm
    acute bronchiolitis with bronchospasm (J21.-)

Excludes2 1

These codes carry an Excludes2 note naming J21: its condition is not part of those codes, and both may be reported when the patient has both.

  • J18.0 Bronchopneumonia, unspecified organism
    acute bronchiolitis (J21.-)

Code Also 1

These codes say J21 may also be needed to fully describe the condition. The note gives no sequencing direction.

  • D81.82 Activated Phosphoinositide 3-kinase Delta Syndrome [APDS]
    other acute respiratory tract infections (J00-J06; J20-J22) names J20-J22, which includes this code

Clinical InformationClinical

  • Acute Bronchiolitis

    acute inflammation of the bronchioles usually caused by the respiratory syncytial virus.

Patient EducationClinical

Bronchial Disorders

When you breathe in, the air travels down through your trachea (windpipe). It then goes through two tubes to your lungs. These tubes are your bronchi. Bronchial disorders can make it hard for you to breathe.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About J21Overview

What is the ICD-10 code for acute bronchiolitis?

J21 is the ICD-10-CM category for acute bronchiolitis, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is J21 (Acute bronchiolitis) a billable code?

No. This is a category header that groups the codes for acute bronchiolitis, and headers cannot be submitted on claims. Claims for acute bronchiolitis need a more specific code from this category, such as J21.0, J21.1, and J21.8.