ICD-10-CM 2027
ICD-10 code for flank wound
Unspecified open wound of abdominal wall, unspecified flank without penetration into peritoneal cavity
From the official ICD-10-CM alphabetic index entry “Wound, open › flank”. Page updated September 29, 2026.
About coding flank wound
The ICD-10-CM code for flank wound is S31.10A (Unspecified open wound of abdominal wall, unspecified flank without penetration into peritoneal cavity). The official index lists 5 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on S31.10A.
Within S31.10, choose S31.10A (unspecified flank without penetration into peritoneal cavity) only when documentation doesn't support a more specific option: right upper quadrant without penetration into peritoneal cavity (S31.100), left upper quadrant without penetration into peritoneal cavity (S31.101), epigastric region without penetration into peritoneal cavity (S31.102), right lower quadrant without penetration into peritoneal cavity (S31.103), left lower quadrant without penetration into peritoneal cavity (S31.104), periumbilic region without penetration into peritoneal cavity (S31.105), right flank without penetration into peritoneal cavity (S31.106), left flank without penetration into peritoneal cavity (S31.107) and 1 more.
Codes in this range require a 7th character: A for initial encounter, D for subsequent encounter and S for sequela. Use placeholder "X" characters to fill any empty positions before the 7th character.
It was added in FY2026, effective October 1, 2025.
More specific flank wound codes (official index)
- with penetration into peritoneal cavity S31.60A — Unspecified open wound of abdominal wall, unspecified flank with penetration into peritoneal cavity
- left S31.107 — Unspecified open wound of abdominal wall, left flank without penetration into peritoneal cavity
- with penetration into peritoneal cavity S31.607 — Unspecified open wound of abdominal wall, left flank with penetration into peritoneal cavity
- right S31.106 — Unspecified open wound of abdominal wall, right flank without penetration into peritoneal cavity
- with penetration into peritoneal cavity S31.606 — Unspecified open wound of abdominal wall, right flank with penetration into peritoneal cavity
Common questions about flank wound ICD-10 codes
What is the ICD-10 code for flank wound?
- S31.10A — Unspecified open wound of abdominal wall, unspecified flank without penetration into peritoneal cavity (a header code; report a more specific subcode). More specific codes apply when the documentation supports them: S31.60A, S31.107, S31.607, S31.106 and others below.
What is the ICD-10 code for left flank wound?
- S31.107 — Unspecified open wound of abdominal wall, left flank without penetration into peritoneal cavity (header code; choose a more specific subcode).
What is the ICD-10 code for right flank wound?
- S31.106 — Unspecified open wound of abdominal wall, right flank without penetration into peritoneal cavity (header code; choose a more specific subcode).
Is S31.10A billable?
- No. S31.10A is a header code. Report one of its more specific subcodes instead.