2026 ICD-10-CM Diagnosis Code S25.509AUnspecified injury of intercostal blood vessels, unspecified side, initial encounter

ICD-10-CM Codes›S00–T88›S20-S29›S25

ICD-10-CM S25.509A
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S25.509A is a billable ICD-10-CM diagnosis code for unspecified injury of intercostal blood vessels, unspecified side, 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 913 through 914, 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 injury of intercostal artery. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Injury to blood vessels, initial encounter.

Code Identity

ICD-10-CM Code
S25.509A
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified injury of intercostal blood vessels, unspecified side, initial encounter
Short Description
Unsp injury of intercostal blood vessels, unsp side, init
Parent Code
S25.509
Unspecified injury of intercostal blood vessels, unspecified side

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS20-S29Injuries to the thorax
CategoryS25Injury of blood vessels of thorax
This CodeS25.509AUnspecified injury of intercostal blood vessels, unspecified side, initial encounter

Code EditsBilling

Medicare Code Editor checks that affect claim validity for S25.509A.

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.

  • Injury of intercostal artery
  • Injury of intercostal vein

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Injury of blood vessels of thorax (S25). 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 INJ016
Injury to blood vessels, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Wounds and Injuries

An injury is damage to your body. It is a general term that refers to harm caused by accidents, falls, hits, weapons, and more. In the U.S., millions of people injure themselves every year. These injuries range from minor to life-threatening.

Read the full article at MedlinePlus

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

Convert S25.509A to ICD-9-CMHistory

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

ICD-9-CM
901.81 Inj intercostal art/vein
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 S25.509AOverview

Is S25.509A a billable code?

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

What does the 7th character A in S25.509A mean?

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

What MS-DRG does S25.509A group to?

When unspecified injury of intercostal blood vessels, unspecified side, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 913, 914, 963, 964, 965, with relative weights from 0.8855 to 2.7338 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of S25.509A?

Under the General Equivalence Mappings, unspecified injury of intercostal blood vessels, unspecified side, initial encounter converts to ICD-9-CM 901.81 (inj intercostal art/vein). 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.