2026 ICD-10-CM Diagnosis Code S27.409AUnspecified injury of bronchus, unspecified, initial encounter

ICD-10-CM Codes›S00–T88›S20-S29›S27

ICD-10-CM S27.409A
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S27.409A is a billable ICD-10-CM diagnosis code for unspecified injury of bronchus, unspecified, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 183 through 185, 963 through 965. The code is flagged as an unspecified code, since codes identifying laterality exist in the same family. Coders also document this condition as bronchopleural fistula. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Internal organ injury, initial encounter.

Code Identity

ICD-10-CM Code
S27.409A
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified injury of bronchus, unspecified, initial encounter
Short Description
Unspecified injury of bronchus, unspecified, init encntr
Parent Code
S27.409
Unspecified injury of bronchus, unspecified

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS20-S29Injuries to the thorax
CategoryS27Injury of other and unspecified intrathoracic organs
This CodeS27.409AUnspecified injury of bronchus, unspecified, initial encounter

Code EditsBilling

Medicare Code Editor checks that affect claim validity for S27.409A.

Unspecified codes
Unspecified codes exist in the ICD-10-CM classification for circumstances when documentation in the medical record does not provide the level of detail needed to support reporting a more specific code. However, in the inpatient setting, there should generally be very limited and rare circumstances for which the laterality (right, left, bilateral) of a condition is unable to be documented and reported. The following pages contain the list of unspecified ICD-10-CM diagnosis codes for which there is a more specific code to identify laterality (right, left, bilateral) within that code family.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bronchopleural fistula
  • Closed injury of bronchus
  • Injury of bronchus
  • Injury of bronchus with open wound into thoracic cavity
  • Injury of bronchus without open wound into thoracic cavity
  • Injury of pleura, lung or bronchus
  • Injury of thoracic cavity
  • Open injury of bronchus
  • Traumatic bronchopleural fistula

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Injury of other and unspecified intrathoracic organs (S27). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INJ010
Internal organ injury, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Chest Injuries and Disorders

The chest is the part of your body between your neck and your abdomen (belly). The medical term for your chest is thorax.

The full article covers:

  • What is the chest?
  • What are chest injuries and disorders?
  • How are chest injuries and disorders diagnosed?

Read the full article at MedlinePlus

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

Convert S27.409A to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
862.21 Bronchus injury-closed
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About S27.409AOverview

Is S27.409A (Unspecified injury of bronchus, unspecified) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unspecified injury of bronchus, unspecified, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in S27.409A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for unspecified injury of bronchus, unspecified, such as an emergency visit or first evaluation.

What MS-DRG does S27.409A group to?

When unspecified injury of bronchus, unspecified, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 183, 184, 185, 963, 964, 965, with relative weights from 0.7865 to 2.7338 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of S27.409A?

Under the General Equivalence Mappings, unspecified injury of bronchus, unspecified, initial encounter converts to ICD-9-CM 862.21 (bronchus injury-closed). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.