ICD-10 Code K51.50 – Left sided colitis without complications (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K51.50 – Left sided colitis without complications
What it is
K51.50 identifies ulcerative colitis limited to the left side of the colon, without documented complications. Use it when the record specifies left-sided involvement and does not describe bleeding, obstruction, or other complications.
Clinical signs
Typical findings include chronic or recurrent diarrhea, abdominal cramping, and rectal bleeding. Endoscopic or pathology reports may show continuous inflammation from the rectum through the descending colon; clinical features vary, refer to documentation.
When to use this code
Use K51.50 when the provider documents left-sided ulcerative colitis, distal colitis, or similar wording and no complication is recorded. It also fits when the note clearly limits disease to the left colon and the encounter is for ongoing management or evaluation.
If the chart states ulcerative colitis but does not specify location, check documentation before coding. Code the most specific confirmed site available, and do not assume extent from symptoms alone.
Do not use for
Do not use this code for pancolitis, proctitis, or unspecified ulcerative colitis. Also avoid it when complications are documented, such as obstruction or fistula; check documentation for the correct code.
Coding tip
Look for anatomic location in the assessment, colonoscopy, or pathology report before assigning K51.50.