2026 ICD-10-CM Diagnosis Code S31.656DOpen bite of abdominal wall, right flank with penetration into peritoneal cavity, subsequent encounter

ICD-10-CM Codes›S00–T88›S30-S39›S31

ICD-10-CM S31.656D
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S31.656D is a billable ICD-10-CM diagnosis code for open bite of abdominal wall, right flank with penetration into peritoneal cavity, 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.

Code Identity

ICD-10-CM Code
S31.656D
Billable Status
Yes — Valid for Submission
Code Describes
Open bite of abdominal wall, right flank with penetration into peritoneal cavity, subsequent encounter
Short Description
Open bite of abd wall, r flank with penet perit cav, subs
Parent Code
S31.656
Open bite of abdominal wall, right flank with penetration into peritoneal cavity

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS30-S39Injuries to the abdomen, lower back, lumbar spine, pelvis and external genitals
CategoryS31Open wound of abdomen, lower back, pelvis and external genitals
This CodeS31.656DOpen bite of abdominal wall, right flank with penetration into peritoneal cavity, subsequent encounter

Present on Admission (POA)Billing

S31.656D is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

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.

Code History & ChangesHistory

New Code S31.656D was added to the ICD-10-CM code set for FY 2026, effective October 1, 2025.

Replacement S31.656D replaces the following previously assigned code(s):

  • S31.659D - Open bite of abd wall, unsp quadrant w penet perit cav, subs
FY 2026AddedAdded to the ICD-10-CM code setEffective October 1, 2025.
FY 2026CurrentRevised in the current code setEffective October 1, 2025 through September 30, 2026.

Questions About S31.656DOverview

Is S31.656D a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report open bite of abdominal wall, right flank with penetration into peritoneal cavity, subsequent encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character D in S31.656D mean?

The final character D marks a subsequent encounter: use it for routine care while the open bite of abdominal wall, right flank with penetration into peritoneal cavity is healing, after active treatment has ended.

What MS-DRG does S31.656D group to?

When open bite of abdominal wall, right flank with penetration into peritoneal cavity, 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 S31.656D 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 open bite of abdominal wall, right flank with penetration into peritoneal cavity, subsequent encounter on inpatient claims.