2026 ICD-10-CM Diagnosis Code S99.919AUnspecified injury of unspecified ankle, initial encounter
S99.919A is a billable ICD-10-CM diagnosis code for unspecified injury of unspecified ankle, 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 ankle. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other unspecified injury.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Injury of ankle
- Multiple injuries of ankle
- Multiple injuries of free lower limb
- Ottawa ankle rules test positive
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Other and unspecified injuries of ankle and foot (S99). 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
Ankle Injuries and Disorders
Your ankle bone and the ends of your two lower leg bones make up the ankle joint. Your ligaments, which connect bones to one another, stabilize and support it. Your muscles and tendons move it.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert S99.919A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S99.919AOverview
Is S99.919A (Unspecified injury of unspecified ankle) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report unspecified injury of unspecified ankle, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in S99.919A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for unspecified injury of unspecified ankle, such as an emergency visit or first evaluation.
What MS-DRG does S99.919A group to?
When unspecified injury of unspecified ankle, 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 S99.919A?
Under the General Equivalence Mappings, unspecified injury of unspecified ankle, initial encounter converts to ICD-9-CM 959.7 (lower leg injury NOS). 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.
