2026 ICD-10-CM Diagnosis Code S39.92XAUnspecified injury of lower back, initial encounter
S39.92XA is a billable ICD-10-CM diagnosis code for unspecified injury of lower back, 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 central cord syndrome of lumbar spinal cord due to traumatic 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.
- Central cord syndrome of lumbar spinal cord due to traumatic injury
- Injury of back
- Injury of back of trunk
- Injury of buttock
- Injury of coccyx
- Lower back injury
- Multiple injuries of lower back
- Traumatic injury of back of neck and trunk
- Traumatic injury of back of trunk
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Other and unspecified injuries of abdomen, lower back, pelvis and external genitals (S39). 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
Back Injuries
Your back is made of bones, muscles, and other tissues extending from your neck to your pelvis. Back injuries can result from sports injuries, work around the house or in the garden, or a sudden jolt such as a car accident. The lower back is the most common site of back injuries and back pain. Common back injuries include :
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert S39.92XA to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S39.92XAOverview
Is S39.92XA (Unspecified injury of lower back) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report unspecified injury of lower back, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in S39.92XA mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for unspecified injury of lower back, such as an emergency visit or first evaluation.
What MS-DRG does S39.92XA group to?
When unspecified injury of lower back, 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 S39.92XA?
Under the General Equivalence Mappings, unspecified injury of lower back, initial encounter converts to ICD-9-CM 959.19 (trunk injury-sites NEC). 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.
