Anal fistula

This code represents an abnormal, chronic tract or tunnel connecting the anal canal or rectum to the perianal skin. It typically results from an infection of the anal glands, leading to an abscess that drains spontaneously or is surgically incised, leaving a persistent communication. Patients often present with recurrent perianal discharge, pain, and swelling.

Assign this code for documented cases of anal fistula, regardless of its complexity (e.g., simple, complex, high, low). It is appropriate when the physician's documentation clearly identifies the presence of a fistula originating from the anal canal or rectum and exiting to the skin. Supporting documentation includes operative reports detailing fistula identification and repair, or clinic notes describing characteristic symptoms and physical exam findings.

• Do not use this code for pilonidal sinus with abscess, which has a separate classification.
• Ensure documentation specifies "anal fistula" and not merely a perianal abscess, as the latter is an acute condition that may or may not lead to a fistula.
• Consider sequencing this code as the primary diagnosis when the fistula is the main reason for the encounter, especially for surgical repair.