ICD-10 Code K51.519 – Left sided colitis with unspecified complications (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K51.519 – Left sided colitis with unspecified complications
What it is
K51.519 identifies ulcerative colitis limited to the left side of the colon when the complication is not specified. Use it when documentation confirms left-sided disease but does not name the exact complication.
Clinical signs
Clinical features vary; refer to documentation. Commonly recorded findings include chronic bloody diarrhea, abdominal cramping, urgency, and inflammation limited to the left colon on endoscopy or imaging.
When to use this code
Use this code when the provider documents left-sided colitis or left-sided ulcerative colitis and also notes a complication, but the complication is not described clearly enough for a more specific code. It also fits when the record supports left-sided involvement and the chart does not identify the exact complication. Check documentation if the term “complicated” is used without detail.
Do not use for
Do not use K51.519 for ulcerative colitis affecting the entire colon, the rectum only, or when no complication is documented. If the complication is named specifically, code that more exact diagnosis instead.
Coding tip
Query for the missing complication when the note says “complicated” but does not define what is complicated.