K35: Acute appendicitis

Codes under K35 (Acute appendicitis). A ✓ marks a billable (fully specified) code; category codes without a ✓ are not billable on their own.

Code	Description	Billable
K35.2	Acute appendicitis with generalized peritonitis	—
K35.3	Acute appendicitis with localized peritonitis	—
K35.8	Other and unspecified acute appendicitis	—
K35.20	Acute appendicitis with generalized peritonitis, without abscess	—
K35.21	Acute appendicitis with generalized peritonitis, with abscess	—
K35.30	Acute appendicitis with localized peritonitis, without perforation or gangrene	✓
K35.31	Acute appendicitis with localized peritonitis and gangrene, without perforation	✓
K35.32	Acute appendicitis with perforation, localized peritonitis, and gangrene, without abscess	✓
K35.33	Acute appendicitis with perforation, localized peritonitis, and gangrene, with abscess	✓
K35.80	Unspecified acute appendicitis	✓
K35.89	Other acute appendicitis	—
K35.200	Acute appendicitis with generalized peritonitis, without perforation or abscess	✓
K35.201	Acute appendicitis with generalized peritonitis, with perforation, without abscess	✓
K35.209	Acute appendicitis with generalized peritonitis, without abscess, unspecified as to perforation	✓
K35.210	Acute appendicitis with generalized peritonitis, without perforation, with abscess	✓
K35.211	Acute appendicitis with generalized peritonitis, with perforation and abscess	✓
K35.219	Acute appendicitis with generalized peritonitis, with abscess, unspecified as to perforation	✓
K35.890	Other acute appendicitis without perforation or gangrene	✓
K35.891	Other acute appendicitis without perforation, with gangrene	✓

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Informational only, not coding or medical advice. Verify against the official ICD-10-CM (FY2026) and your payer's guidelines.

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