2026 ICD-10-CM Diagnosis Code S43.203AUnspecified subluxation of unspecified sternoclavicular joint, initial encounter

ICD-10-CM Codes›S00–T88›S40-S49›S43

ICD-10-CM S43.203A
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S43.203A is a billable ICD-10-CM diagnosis code for unspecified subluxation of unspecified sternoclavicular joint, 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 closed traumatic subluxation of sternum. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Dislocations, initial encounter.

Code Identity

ICD-10-CM Code
S43.203A
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified subluxation of unspecified sternoclavicular joint, initial encounter
Short Description
Unsp subluxation of unsp sternoclavicular joint, init encntr
Parent Code
S43.203
Unspecified subluxation of unspecified sternoclavicular joint

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS40-S49Injuries to the shoulder and upper arm
CategoryS43Dislocation and sprain of joints and ligaments of shoulder girdle
This CodeS43.203AUnspecified subluxation of unspecified sternoclavicular joint, initial encounter

Code EditsBilling

Medicare Code Editor checks that affect claim validity for S43.203A.

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.

  • Closed traumatic subluxation of sternum
  • Closed traumatic subluxation sternoclavicular joint
  • Fracture dislocation of sternoclavicular joint
  • Fracture subluxation of sternoclavicular joint
  • Open traumatic dislocation sternoclavicular joint
  • Open traumatic subluxation of sternum
  • Open traumatic subluxation sternoclavicular joint
  • Subluxation of sternoclavicular joint

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Dislocation and sprain of joints and ligaments of shoulder girdle (S43). 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 INJ007
Dislocations, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Dislocated Shoulder

Your shoulder joint is made up of three bones: your collarbone, your shoulder blade, and your upper arm bone. The top of your upper arm bone is shaped like a ball. This ball fits into a cuplike socket in your shoulder blade. A shoulder dislocation is an injury that happens when the ball pops out of your socket.

The full article covers:

  • What is a dislocated shoulder?
  • What causes a dislocated shoulder?
  • Who is at risk for a dislocated shoulder?
  • What are the symptoms of a dislocated shoulder?
  • How is a dislocated shoulder diagnosed?
  • What are the treatments for a dislocated shoulder?

Read the full article at MedlinePlus

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

Convert S43.203A to ICD-9-CMHistory

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

ICD-9-CM
839.61 Dislocat sternum-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 S43.203AOverview

Is S43.203A a billable code?

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

What does the 7th character A in S43.203A mean?

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

What MS-DRG does S43.203A group to?

When unspecified subluxation of unspecified sternoclavicular joint, 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 S43.203A?

Under the General Equivalence Mappings, unspecified subluxation of unspecified sternoclavicular joint, initial encounter converts to ICD-9-CM 839.61 (dislocat sternum-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.