ICD-10-CM > K00-K95 > K35-K38 > K35 > K35.8 K35.8 Other and unspecified acute appendicitis Non-Billable/Non-Specific Codes K35.80Unspecified acute appendicitisK35.89Other acute appendicitisK35.890Other acute appendicitis without perforation or gangreneK35.891Other acute appendicitis without perforation, with gangrene