2027 ICD-10-CM Diagnosis Code S25.329AMajor laceration of unspecified innominate or subclavian vein, initial encounter

ICD-10-CM Codes›S00–T88›S20-S29›S25

ICD-10-CM S25.329A
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

S25.329A is a billable ICD-10-CM diagnosis code for major laceration of unspecified innominate or subclavian vein, 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 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 791, 793, 913 through 914, 963 through 965. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. It does not count, however, when the principal diagnosis is one of 27 closely related codes. The code is flagged as an unspecified code, since codes identifying laterality exist in the same family. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Injury to blood vessels, initial encounter.

Code Identity

ICD-10-CM Code
S25.329A
Billable Status
Yes — Valid for Submission
Code Describes
Major laceration of unspecified innominate or subclavian vein, initial encounter
Short Description
Major laceration of unsp innominate or subclavian vein, init
Parent Code
S25.329
Major laceration of unspecified innominate or subclavian vein

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS20-S29Injuries to the thorax
CategoryS25Injury of blood vessels of thorax
This CodeS25.329AMajor laceration of unspecified innominate or subclavian vein, initial encounter

Code EditsBilling

Medicare Code Editor checks that affect claim validity for S25.329A.

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.

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 2027, published by CMS and the National Center for Health Statistics.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to S25.329A: its own notes plus those printed at S25, block S20-S29, and Chapter 19. 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.

From Block S20-S29 Injuries to the thorax applies to 1,602 codes
  • injuries of breast
  • injuries of chest (wall)
  • injuries of interscapular area

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.

From Block S20-S29 Injuries to the thorax applies to 1,602 codes
  • burns and corrosions (T20-T32)
  • effects of foreign body in bronchus (T17.5)
  • effects of foreign body in esophagus (T18.1)
  • effects of foreign body in lung (T17.8)
  • effects of foreign body in trachea (T17.4)
  • frostbite (T33-T34)
  • injuries of axilla
  • injuries of clavicle
  • injuries of scapular region
  • injuries of shoulder
  • insect bite or sting, venomous (T63.4)
From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes

Use Additional Code

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

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • code to identify any retained foreign body, if applicable (Z18.-)

Code Also

A second code may be needed to fully describe the condition; the note gives no sequencing direction.

From S25 Injury of blood vessels of thorax applies to 195 codes
  • any associated open wound (S21.-)

Notes

General instructions on how these codes are used.

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
  • The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.

7th Character

Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.

From S25 Injury of blood vessels of thorax applies to 195 codes
  • The appropriate 7th character is to be added to each code from category S25
Values for category S25 Encounter: Initial, Subsequent, Sequela
  • Ainitial encounter this code
  • Dsubsequent encounter
  • Ssequela

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

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name S25.329A, its category, or a range that includes it.

Excludes2 1

These codes carry an Excludes2 note naming S25.329A: its condition is not part of those codes, and both may be reported when the patient has both.

  • S45 Injury of blood vessels at shoulder and upper arm level
    injury of subclavian vein (S25.3) names S25.3, which includes this code

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 S25.329A to ICD-9-CMHistory

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

ICD-9-CM
901.3 Inj innomin/subclav 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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About S25.329AOverview

Is S25.329A a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report major laceration of unspecified innominate or subclavian vein, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What does the 7th character A in S25.329A mean?

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

What MS-DRG does S25.329A group to?

When major laceration of unspecified innominate or subclavian vein, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 793, 791, 964, 965, 914, 913, 963, with relative weights from 0.9281 to 4.2192 depending on complications. Higher weights mean higher Medicare reimbursement.

Is S25.329A a CC or MCC?

CMS lists S25.329A as an MCC (major complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It does not count when the principal diagnosis is one of the 27 closely related codes in its exclusion list.

What is the ICD-9 equivalent of S25.329A?

Under the General Equivalence Mappings, major laceration of unspecified innominate or subclavian vein, initial encounter converts to ICD-9-CM 901.3 (inj innomin/subclav vein). The mapping is approximate, so confirm the match fits the documentation.