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  6. 2026 ICD-10-CM Code S31.10AA

2026 ICD-10-CM Diagnosis Code S31.10AA

Unspecified open wound of abdominal wall, unspecified flank without penetration into peritoneal cavity, initial encounter

ICD-10-CM Code:
S31.10AA
ICD-10 Code for:
Unsp opn wnd abd wall, unsp flank w/o penet perit cav, init
Is Billable?
Yes - Valid for Submission
Code Navigator:

S31.10AA is a billable diagnosis code used to specify a medical diagnosis of unspecified open wound of abdominal wall, unspecified flank without penetration into peritoneal cavity, initial encounter. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2025 through September 30, 2026.

S31.10AA is an initial encounter code, includes a 7th character and should be used while the patient is receiving active treatment for a condition like unspecified open wound of abdominal wall unspecified flank without penetration into peritoneal cavity. According to ICD-10-CM Guidelines an "initial encounter" doesn't necessarily means "initial visit". The 7th character should be used when the patient is undergoing active treatment regardless if new or different providers saw the patient over the course of a treatment. The appropriate 7th character codes should also be used even if the patient delayed seeking treatment for a condition.

Unspecified diagnosis codes like S31.10AA are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

Code Classification

  • Injury, poisoning and certain other consequences of external causes
    S00–T88
    • Injuries to the abdomen, lower back, lumbar spine, pelvis and external genitals
      S30-S39
      • Open wound of abdomen, lower back, pelvis and external genitals
        S31

Coding Guidelines

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 aplicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

New 2026 ICD-10-CM Code

S31.10AA is new to ICD-10-CM code set for the FY 2026, effective October 1, 2025. The National Center for Health Statistics (NCHS) has published an update to the ICD-10-CM diagnosis codes which became effective October 1, 2025. This is a new and revised code for the FY 2026 (October 1, 2025 - September 30, 2026).

Replacement Code

S3110AA replaces the following previously assigned ICD-10-CM code(s):

  • S31.109A - Unsp opn wnd abd wall, unsp q w/o penet perit cav, init

Code History

  • FY 2026 - Code Added, effective from 10/1/2025 through 9/30/2026