What ICD-10-CM code should be reported for acute appendicitis with peritoneal abscess?

The appropriate ICD-10-CM code for acute appendicitis with peritoneal abscess is K35.3. This code specifically identifies acute appendicitis that has progressed to the formation of a peritoneal abscess, which is a significant complication indicating that the condition has worsened beyond simple inflammation.

The classification system for ICD-10-CM includes specific codes to describe the type and severity of appendicitis. K35.0 refers to acute appendicitis without mention of complications, K35.1 refers to acute appendicitis with generalized peritonitis, and K35.2 indicates acute appendicitis with localized peritonitis. None of these codes are appropriate for cases involving peritoneal abscess, which is why K35.3 is the correct code. It clearly denotes the presence of a serious complication related to appendicitis, providing precise information for medical coding and billing purposes.