Acute Appendicitis ICD-10-CM Codes

What ICD-10 Codes are Used for Acute Appendicitis 

Here are several acute appendicitis ICD codes you can use for patients with acute appendicitis:

• K35.20 - Acute appendicitis with generalized peritonitis, without abscess

This ICD-10 code is meant to be used on a patient confirmed to have acute appendicitis (the inflammation of the appendix) and generalized peritonitis (the inflammation of the peritoneum). Despite having these, the patient has no abscesses.

• K35.21 - Acute appendicitis with generalized peritonitis, with abscess

This is the same as Item 1, but this time, there is an abscess.

• K35.30 - Acute appendicitis with localized peritonitis, without perforation or gangrene

This ICD-10 code is meant to be used on a patient with acute appendicitis with localized peritonitis (this type of peritonitis is confined in a certain region of the peritoneal cavity). Despite having both of these, the patient has no perforation (holes) and gangrene (tissue death due to bacterial infections/lack of blood flow).

• K35.31 - Acute appendicitis with localized peritonitis and gangrene, without perforation

This is the same as Item 3, but this time, the patient has gangrene but no perforations.

• K35.32 - Acute appendicitis with perforation, localized peritonitis, and gangrene, without abscess

This is the same as Item 3, but this time, the patient has perforations and gangrene, but there are no abscesses.

• K35.33 - Acute appendicitis with perforation, localized peritonitis, and gangrene, with abscess

This is the same as Item 5, but the patient has abscesses this time.

Are these acute appendicitis ICD codes billable?

Yes. All the aforementioned acute appendicitis-related ICD-10 codes are valid and billable.

Clinical information

• Appendicitis is the inflammation of the appendix. 
• The appendix is this small, worm-shaped muscular structure located on the first part of the large intestine. 
• The appendix's function is unknown, but recent efforts in research suggest that the appendix might be serving as a reservoir for beneficial gut flora, but this remains to be fully proven and finalized.
• If the appendix becomes inflamed, it will cause pain in the lower right abdomen. 
• If left unchecked and treated, the pain will heighten over time and may lead to complications such as abscesses, perforations, peritonitis, and gangrene. 

Synonyms include:

• Acute appendicitis with generalized peritonitis
• Acute appendicitis with peritonitis
• Acute obstructive appendicitis
• Acute obstructive appendicitis with perforation AND peritonitis
• Acute perforated appendicitis
• Acute appendicitis with localized peritonitis
• Rupture of appendix
• Ruptured suppurative appendicitis
• Suppurative appendicitis
• Abscess of appendix
• Acute fulminating appendicitis
• Acute gangrenous appendicitis
• Gangrenous appendicitis