ICD-10 Code K51.013 – Ulcerative (chronic) pancolitis with fistula (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K51.013 – Ulcerative (chronic) pancolitis with fistula
What it is
K51.013 identifies chronic ulcerative colitis affecting the entire colon, with a fistula present. Use it when documentation shows pancolitis and an abnormal connection between the bowel and another structure.
Clinical signs
Typical findings include chronic inflammatory bowel disease with diffuse colonic involvement and a documented fistula. Clinical features vary; refer to documentation for the fistula location and whether the disease is active or chronic.
When to use this code
Use this code when the record specifically states ulcerative colitis involving the whole colon and confirms a fistula. It may appear in gastroenterology, surgical, or discharge documentation. If fistula type or extent is unclear, check documentation.
Do not use for
Do not use it for ulcerative colitis without pancolitis, or for Crohn disease with fistula. Do not assign it if the chart mentions fistula only as a suspected finding.
Coding tip
Verify both elements—pancolitis and fistula—before coding, because either missing detail changes the code selection.