Is ICD-10-CM code J21 billable?

No, J21 (Acute bronchiolitis) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code J21 belong to?

J21 belongs to Chapter 10 of the ICD-10-CM tabular list: J00–J99 (Diseases of the Respiratory System).

J21Not billable, use a more specific code below

Acute bronchiolitis

In Other acute lower respiratory infections (J20-J22), chapter 10: Diseases of the Respiratory System

4 billable codes under J21: all are a CC; none map to an HCC.A CC or MCC (major CC) is a secondary diagnosis that raises the MS-DRG payment.

Instructional notes

Includes: conditions that are coded here

acute bronchiolitis with bronchospasm

Excludes2: not included here, code separately if applicable

respiratory bronchiolitis interstitial lung disease (J84.115)

Also applies, from Other acute lower respiratory infections (J20-J22)

These notes sit on J20-J22 and apply to every code under it, including J21.

Excludes2: not included here, code separately if applicable

chronic obstructive pulmonary disease with acute lower respiratory infection (J44.0)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Covers COPD and asthma exacerbations, sequencing of acute respiratory failure, confirmed versus suspected identified influenza, ventilator associated pneumonia, and vaping-related disorders.

Chronic Obstructive Pulmonary Disease [COPD] and Asthma (page 56)
Acute Respiratory Failure (page 56)
Influenza due to certain identified influenza viruses (page 57)
Ventilator associated Pneumonia (page 57)
Vaping-related disorders (page 58)

Read Section I.C.10 (page 56)

All codes under J21

J21 can't be used on a claim. Pick a billable code below; grey headings group them.

J21 MS-DRGs

As the principal diagnosis, all 4 billable codes under J21 group to MS-DRG 202 or 203 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

Other codes that refer to J21

Notes on these codes point to J21.

J18.0 Excludes2: acute bronchiolitis (J21.-)
J98.01 Excludes1: acute bronchiolitis with bronchospasm (J21.-)

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

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.

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.