2026 ICD-10-CM Diagnosis Code S31.40XAUnspecified open wound of vagina and vulva, initial encounter
S31.40XA is a billable ICD-10-CM diagnosis code for unspecified open wound of vagina and vulva, 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 742 through 743, 760 through 761, 963 through 965. Coders also document this condition as labia - open wound. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Open wounds of trunk, initial encounter.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Labia - open wound
- Open wound of labium majus
- Open wound of labium minus
- Open wound of vagina
- Open wound of vulva
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Open wound of abdomen, lower back, pelvis and external genitals (S31). 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
Vaginal Diseases
Vaginal problems are some of the most common reasons women go to the doctor. They may have symptoms such as:
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Convert S31.40XA to ICD-9-CMHistory
Code HistoryHistory
Questions About S31.40XAOverview
Is S31.40XA (Unspecified open wound of vagina and vulva) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report unspecified open wound of vagina and vulva, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in S31.40XA mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for unspecified open wound of vagina and vulva, such as an emergency visit or first evaluation.
What MS-DRG does S31.40XA group to?
When unspecified open wound of vagina and vulva, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 742, 743, 760, 761, 963, 964, 965, with relative weights from 0.5696 to 2.7338 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of S31.40XA?
Under the General Equivalence Mappings, unspecified open wound of vagina and vulva, initial encounter converts to ICD-9-CM 878.4 (open wound of vulva) and 878.6 (open wound of vagina). 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.
