ICD-10 Code K35.200 – Acute appendicitis with generalized peritonitis, without perforation or abscess (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K35.200 – Acute appendicitis with generalized peritonitis, without perforation or abscess
What it is
This code identifies acute inflammation of the appendix with generalized peritonitis, but without documented perforation or abscess. Use it when the record clearly supports diffuse peritoneal involvement and does not describe a rupture or localized collection.
Clinical signs
Typical findings include acute abdominal pain, guarding, rebound tenderness, and generalized peritoneal irritation. Clinical features vary; refer to documentation for the surgeon’s or clinician’s description of peritonitis and any imaging or operative findings.
When to use this code
Use K35.200 when the provider documents acute appendicitis with generalized peritonitis and explicitly states there is no perforation or abscess. It may also fit operative, imaging, or discharge documentation that confirms diffuse peritoneal inflammation without a stated rupture. If the record is unclear, check documentation.
Do not use for
Do not use this code if the chart documents perforation, appendiceal abscess, or a different type of appendicitis. If generalized peritonitis is not documented, or the diagnosis is uncertain, check documentation before coding.
Coding tip
Match the code to the provider’s exact wording and avoid assuming perforation or abscess when they are not stated.