2026 ICD-10-CM Diagnosis Code S85.131AUnspecified injury of anterior tibial artery, right leg, initial encounter
S85.131A is a billable ICD-10-CM diagnosis code for unspecified injury of anterior tibial artery, right leg, 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. Coders also document this condition as injury of anterior tibial artery. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Injury to blood vessels, initial encounter.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Injury of anterior tibial artery
- Injury of right tibial artery
- Traumatic injury of right anterior tibial artery
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Injury of blood vessels at lower leg level (S85). 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
Leg Injuries and Disorders
Your legs are made up of bones, blood vessels, muscles, and other connective tissue. They are important for motion and standing. Playing sports, running, falling, or having an accident can damage your legs. Common leg injuries include sprains and strains, joint dislocations, and fractures (broken bones).
Read the full article at MedlinePlus
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Convert S85.131A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S85.131AOverview
Is S85.131A (Unspecified injury of anterior tibial artery, right leg) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report unspecified injury of anterior tibial artery, right leg, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in S85.131A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for unspecified injury of anterior tibial artery, right leg, such as an emergency visit or first evaluation.
What MS-DRG does S85.131A group to?
When unspecified injury of anterior tibial artery, right leg, 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 S85.131A?
Under the General Equivalence Mappings, unspecified injury of anterior tibial artery, right leg, initial encounter converts to ICD-9-CM 904.51 (inj anter tibial artery). 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.
