ICD-10-CM K35: Acute appendicitis

ICD-10-CM Diagnosis Code (2025)

Official Description for K35

Acute appendicitis

Coding Notes & Guidelines for K35

Inclusion Terms

(Acute) appendicitis with generalized peritonitis without rupture or perforation of appendix NOS

Inclusion Terms

Appendicitis (acute) with generalized (diffuse) peritonitis following rupture or perforation of appendix NOS

Inclusion Terms

(Acute) appendicitis with generalized peritonitis NOS

Inclusion Terms

(Acute) appendicitis with generalized peritonitis without rupture or perforation of appendix, with abscess

Inclusion Terms

Appendicitis (acute) with generalized (diffuse) peritonitis following rupture or perforation of appendix, with abscess

Inclusion Terms

(Acute) appendicitis with generalized peritonitis and abscess NOS

Inclusion Terms

Acute appendicitis with localized peritonitis NOS

Inclusion Terms
  • (Acute) appendicitis with perforation NOS
  • Perforated appendix NOS
  • Ruptured appendix (with localized peritonitis) NOS
Inclusion Terms
  • (Acute) appendicitis with (peritoneal) abscess NOS
  • Ruptured appendix with localized peritonitis and abscess
Inclusion Terms
  • Acute appendicitis NOS
  • Acute appendicitis without (localized) (generalized) peritonitis
Inclusion Terms

(Acute) appendicitis with gangrene NOS

Child Codes (More Specific Codes for K35):

K35.2 - Acute appendicitis with generalized peritonitis K35.20 - Acute appendicitis with generalized peritonitis, without abscess 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 abscess 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 peritonitis 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 appendicitis K35.80 - Unspecified acute appendicitis K35.89 - Other acute appendicitis K35.890 - Other acute appendicitis without perforation or gangrene K35.891 - Other acute appendicitis without perforation, with gangrene

About ICD-10-CM Code K35 (Acute appendicitis)

ICD-10-CM code K35 is a billable or specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. The 2025 edition of ICD-10-CM K35 became effective on October 1, 2024.

This page provides detailed information about K35 - Acute appendicitis. It includes common terminology, coding guidelines such as "Includes," "Excludes1," and "Excludes2" notes, and information on required 7th characters. Utilizing this information correctly is essential for accurate medical coding and claims submission for conditions like Acute appendicitis.