ICD-10 Code K65.8 – Other peritonitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K65.8 – Other peritonitis
What it is
K65.8 identifies peritonitis that is not classified elsewhere in ICD-10-CM. Use it when the peritoneal inflammation is documented, but the specific type does not fit a more exact code.
Clinical signs
Clinical features vary; refer to documentation. Typical findings may include abdominal pain, tenderness, guarding, distention, fever, or other signs of intra-abdominal inflammation.
When to use this code
Use K65.8 when the provider documents other peritonitis and the record does not support a more specific peritonitis code. It may apply when the cause or subtype is described but not indexed to a separate category. Check documentation for whether the condition is infectious, postprocedural, or secondary to another abdominal disorder.
Do not use for
Do not use K65.8 for generalized, acute, or chronic peritonitis when a more specific code is documented. Also avoid it when the record supports a different underlying diagnosis rather than peritonitis itself.
Coding tip
Review the provider’s exact wording and index the documented peritonitis type before defaulting to K65.8.