ICD-10 Code K51.818 – Other ulcerative colitis with other complication (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K51.818 – Other ulcerative colitis with other complication
What it is
This code identifies ulcerative colitis with an additional documented complication that does not fit a more specific K51.8x category. Use it when the chart states ulcerative colitis plus another complication, but not one named elsewhere.
Clinical signs
Clinical features vary; refer to documentation. Typical ulcerative colitis findings may include chronic bloody diarrhea, abdominal pain, urgency, and rectal bleeding, with the added complication noted in the record.
When to use this code
Use K51.818 when the provider documents ulcerative colitis and a separate complication, and no more specific code applies. Confirm the complication is part of the current assessment, not only a past history item. If the complication is named elsewhere in the code set, choose the more specific code instead.
Do not use for
Do not use this code for ulcerative colitis without a documented complication, or when the chart specifies a different ulcerative colitis subtype. Check documentation if the complication is unclear or not linked to the colitis.
Coding tip
Code the ulcerative colitis and the complication only when the provider clearly links them in the note.