All ICD10 Codes
K51Not billable, use a more specific code below

Ulcerative colitis

In Noninfective enteritis and colitis (K50-K52), chapter 11: Diseases of the Digestive System

49 billable codes under K51: all are a CC; all map to HCC 81 (Ulcerative Colitis), HCC 78 (Intestinal Obstruction/Perforation).A CC or MCC (major CC) is a secondary diagnosis that raises the MS-DRG payment. An HCC counts toward a Medicare Advantage patient's risk score.

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Instructional notes

Excludes1: not coded here, use a different code

  • Crohn's disease [regional enteritis] (K50.-)

Use additional code: add a second code for this, listed after this one

  • code to identify any associated fistulas, if applicable:
  • anal fistula (K60.3-)
  • anorectal fistula (K60.5-)
  • rectal fistula (K60.4-)
  • code to identify manifestations, such as:
  • pyoderma gangrenosum (L88)

Also applies, from Noninfective enteritis and colitis (K50-K52)

These notes sit on K50-K52 and apply to every code under it, including K51.

Includes: conditions that are coded here

  • noninfective inflammatory bowel disease

Excludes1: not coded here, use a different code

  • irritable bowel syndrome (K58.-)
  • megacolon (K59.3-)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

There are no chapter-specific rules for Chapter 11 yet, so the general rules in Section I.B apply.

Read Section I.C.11 (page 58)

All codes under K51

K51 can't be used on a claim. Pick a billable code below; grey headings group them.

K51 MS-DRGs

As the principal diagnosis, all 49 billable codes under K51 group to MS-DRG 385, 386, or 387 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

Other codes that refer to K51

Notes on these codes point to K51.

  • F54 Code First: ulcerative colitis (K51.-)
  • K50 Excludes1: ulcerative colitis (K51.-)
  • K60.3 Code First: ulcerative colitis (K51.-)
  • K60.4 Code First: ulcerative colitis (K51.-)
  • K60.5 Code First: ulcerative colitis (K51.-)
  • K62.6 Excludes1: ulcerative colitis (K51.-)
  • K63.3 Excludes1: ulcerative colitis (K51.-)
  • M07 Code Also: ulcerative colitis (K51.-)
  • M08 Code Also: ulcerative colitis (K51.-)

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

Ulcerative Colitis

Ulcerative colitis (UC) is a disease that causes inflammation and sores, called ulcers, in the lining of the rectum and colon. It is one of a group of diseases called inflammatory bowel disease.

Read more about ulcerative colitis on MedlinePlus

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.