MCMCB Pro
K51

K51Ulcerative colitis

Non-billable headerICD-10-CM

K51 is a non-billable header ICD-10-CM code for ulcerative colitis. It cannot be billed on its own: choose one of the more specific child codes below.

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

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

Use additional code

Add a secondary code to capture the detail described below.

  • 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)

Other codes that can never be billed with K51

These codes carry an Excludes1 note pointing at K51. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading K51 alone.

  • R58Hemorrhage, not elsewhere classified
  • K50Crohn's disease [regional enteritis]
  • K62.6Ulcer of anus and rectum
  • K63.0Abscess of intestine
  • K63.2Fistula of intestine
  • K63.3Ulcer of intestine

Risk adjustment

K51 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Code to one of these instead K51

7 child codes. Green means billable.

Questions about K51

Is K51 a billable ICD-10-CM code?
No. K51 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does K51 sit in the tabular list?
Diseases of the digestive system (K00-K95), in the block Noninfective enteritis and colitis (K50-K52).
What cannot be coded together with K51?
K51 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.