2026 ICD-10-CM Diagnosis Code S27.391SOther injuries of lung, unilateral, sequela
S27.391S is a billable ICD-10-CM diagnosis code for other injuries of lung, unilateral, sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 205 through 206. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Injury, sequela.
Code Identity
Code Classification
Present on Admission (POA)Billing
S27.391S is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.
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.
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 S27.391S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S27.391SOverview
Is S27.391S (Other injuries of lung, unilateral) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report other injuries of lung, unilateral, sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in S27.391S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the other injuries of lung, unilateral itself has resolved, not the original event.
What MS-DRG does S27.391S group to?
When other injuries of lung, unilateral, sequela is the principal diagnosis on an inpatient stay, it groups to MS-DRG 205, 206, with relative weights from 0.9411 to 1.8310 depending on complications. Higher weights mean higher Medicare reimbursement.
Is S27.391S exempt from POA reporting?
Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for other injuries of lung, unilateral, sequela on inpatient claims.
What is the ICD-9 equivalent of S27.391S?
Under the General Equivalence Mappings, other injuries of lung, unilateral, sequela converts to ICD-9-CM 908.0 (late eff int injur chest). 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.
