Acute appendicitis (K35) ICD-10-CM
The K35 code range covers acute appendicitis with 20 ICD-10-CM diagnosis codes. 13 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Codes in the K35 Range 20 codes · 13 billable
- K35 Acute appendicitisNon-billable
- K35.2 Acute appendicitis with generalized peritonitisNon-billable
- K35.20 Acute appendicitis with generalized peritonitis, without abscessNon-billable
- 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
- K35.21 Acute appendicitis with generalized peritonitis, with abscessNon-billable
- 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
- K35.3 Acute appendicitis with localized peritonitisNon-billable
- 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
- K35.8 Other and unspecified acute appendicitisNon-billable
- K35.80 Unspecified acute appendicitis
- K35.89 Other acute appendicitisNon-billable
- K35.890 Other acute appendicitis without perforation or gangrene
- K35.891 Other acute appendicitis without perforation, with gangrene
About the K35 Code Range
The ICD-10 code K35 and its subcategories specifically identify different forms of acute appendicitis, ranging from simple inflammation to complicated cases with peritonitis, perforation, abscess, or gangrene. These codes are essential for precisely documenting the exact nature and severity of appendicitis in medical records.
The ICD-10 code for acute appendicitis K35 covers uncomplicated inflammation, while detailed codes like K35.2 refer to appendicitis with generalized peritonitis, including variations with or without abscess and perforation. For example, K35.209 describes acute appendicitis with generalized peritonitis without specifying perforation, linked to terms like "acute appendicitis with peritonitis." Codes such as K35.3 and its extensions address localized peritonitis cases, some involving gangrene or perforation, with various synonymous clinical terms like "perforation of appendix" and "ruptured suppurative appendicitis." Additionally, K35.8 and K35.89 classify unspecified or other acute appendicitis forms, including gangrenous appendicitis and suppurative appendicitis. Using these codes helps healthcare professionals and coders document the precise diagnosis for treatment decisions and accurate health data reporting.
Questions About This Page
How many billable codes are in the K35 range?
Of the 20 codes in this range, 13 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the K35 range classify?
The range classifies acute appendicitis. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
