2026 ICD-10-CM Diagnosis Code S31.839DUnspecified open wound of anus, subsequent encounter
S31.839D is a billable ICD-10-CM diagnosis code for unspecified open wound of anus, subsequent encounter. The 7th character D marks it as a subsequent encounter code, used during routine care in the healing or recovery phase. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 949 through 950. The code is exempt from POA reporting. Coders also document this condition as open wound of anus. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Open wounds of trunk, subsequent encounter.
Code Identity
Code Classification
Present on Admission (POA)Billing
S31.839D is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Open wound of anus
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
Wounds and Injuries
An injury is damage to your body. It is a general term that refers to harm caused by accidents, falls, hits, weapons, and more. In the U.S., millions of people injure themselves every year. These injuries range from minor to life-threatening.
Read the full article at MedlinePlus
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Convert S31.839D to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S31.839DOverview
Is S31.839D (Unspecified open wound of anus) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report unspecified open wound of anus, subsequent encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character D in S31.839D mean?
The final character D marks a subsequent encounter: use it for routine care while the unspecified open wound of anus is healing, after active treatment has ended.
What MS-DRG does S31.839D group to?
When unspecified open wound of anus, subsequent encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 949, 950, with relative weights from 0.6277 to 1.1897 depending on complications. Higher weights mean higher Medicare reimbursement.
Is S31.839D exempt from POA reporting?
Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for unspecified open wound of anus, subsequent encounter on inpatient claims.
What is the ICD-9 equivalent of S31.839D?
Under the General Equivalence Mappings, unspecified open wound of anus, subsequent encounter converts to ICD-9-CM V58.89 (other specfied aftercare). 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.
