ICD-10-CM > K00-K95 > K35-K38 > K35 > K35.2 > K35.21 K35.21 Acute appendicitis with generalized peritonitis, with abscess Non-Billable/Non-Specific Codes K35.210Acute appendicitis with generalized peritonitis, without perforation, with abscessK35.211Acute appendicitis with generalized peritonitis, with perforation and abscessK35.219Acute appendicitis with generalized peritonitis, with abscess, unspecified as to perforation