ICD-10 Code K51.813 – Other ulcerative colitis with fistula (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K51.813 – Other ulcerative colitis with fistula
What it is
K51.813 identifies ulcerative colitis, a chronic inflammatory bowel disease, when a fistula is documented. Use it for cases that are not classified as another specific ulcerative colitis subtype.
Clinical signs
Clinical features may include chronic diarrhea, rectal bleeding, abdominal pain, and evidence of an abnormal connection between bowel segments or nearby organs. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider documents ulcerative colitis and a fistula, and the record does not specify a more exact ulcerative colitis category. It may appear in problem lists, discharge summaries, or specialist notes. Verify that the fistula is part of the documented diagnosis.
Do not use for
Do not use it for Crohn disease with fistula or for ulcerative colitis without a documented fistula. Check documentation if the fistula type or IBD subtype is unclear.
Coding tip
Assign the code only when both ulcerative colitis and fistula are clearly documented together.