ICD-10 Code K61.3 – Ischiorectal abscess (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K61.3 – Ischiorectal abscess
What it is
K61.3 identifies an abscess in the ischiorectal fossa, a deep space beside the anal canal. It means there is a localized collection of pus in this anorectal region.
Clinical signs
Patients may have deep perianal pain, swelling, and tenderness, sometimes with fever or difficulty sitting. Clinical features vary; refer to documentation.
When to use this code
Use K61.3 when the provider documents an ischiorectal abscess, ischiorectal fossa abscess, or equivalent wording. Code it when the diagnosis is confirmed and the record clearly identifies this specific anorectal location.
If the note only says “perianal abscess” or another anorectal abscess site, check documentation before assigning K61.3. You should not assume the ischiorectal space unless it is stated.
Do not use for
Do not use this code for a nonspecific abscess without location, or for other perirectal or perianal abscess sites. Check documentation if the anatomic site is unclear.
Coding tip
Match the code to the exact abscess location; the anatomic term in the provider note should drive selection.