2027 ICD-10-CM Diagnosis Code S79.921AUnspecified injury of right thigh, initial encounter
S79.921A is a billable ICD-10-CM diagnosis code for unspecified injury of right thigh, 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 913 through 914, 963 through 965. Coders also document this condition as right thigh injury. 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.
- Right thigh injury
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Other and unspecified injuries of hip and thigh (S79). 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 S79.921A: its own notes plus those printed at S79.9, S79, block S70-S79, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.
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.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify any retained foreign body, if applicable (Z18.-)
Notes
General instructions on how these codes are used.
- A fracture not indicated as open or closed should be coded to closed
- 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.
- The appropriate 7th character is to be added to each code in subcategory S79.9
- The appropriate 7th character is to be added to each code from subcategories S79.0 and S79.1
- Ainitial encounter this code
- Dsubsequent encounter
- Ssequela
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
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
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert S79.921A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S79.921AOverview
What is the ICD-10 code for unspecified injury of right thigh, initial encounter?
The ICD-10-CM code for unspecified injury of right thigh, initial encounter is S79.921A (sometimes written as S79921A). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is S79.921A (Unspecified injury of right thigh) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report unspecified injury of right thigh, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character A in S79.921A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for unspecified injury of right thigh, such as an emergency visit or first evaluation.
What MS-DRG does S79.921A group to?
When unspecified injury of right thigh, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 964, 965, 914, 913, 963, with relative weights from 0.9281 to 2.6361 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of S79.921A?
Under the General Equivalence Mappings, unspecified injury of right thigh, initial encounter converts to ICD-9-CM 959.6 (hip & thigh injury NOS). The mapping is approximate, so confirm the match fits the documentation.
