In simple words: This code refers to a sudden inflammation of the appendix, a small pouch attached to the large intestine, without specifying any further details about complications like infection or rupture.

Unspecified acute appendicitis. This code is used when the documentation does not specify whether there is peritonitis, perforation, abscess, or gangrene associated with the acute appendicitis.

Example 1: A 15-year-old patient presents with acute abdominal pain migrating to the right lower quadrant, nausea, and vomiting. The physician suspects acute appendicitis, but imaging and clinical findings are inconclusive regarding peritonitis, perforation, or gangrene. K35.80 is used until further clarification., A 25-year-old patient reports sudden onset of right lower quadrant abdominal pain. Physical exam findings suggest appendicitis, but the extent of the inflammation is not immediately clear from the initial examination. K35.80 is assigned pending further diagnostic workup., A patient with a history of abdominal pain is admitted for an appendectomy. The operative report notes acute appendicitis but does not specify the presence or absence of peritonitis or perforation. In this case, K35.80 may be applied if the other documentation does not provide those details.

Documentation should include details of the present illness, including onset, location, character, and radiation of pain, associated symptoms, physical examination findings, and results of imaging studies (e.g., ultrasound, CT scan). Lab results, including white blood cell count, are also relevant.