K51 Ulcerative colitis

Category / Non-billable header 63 subcodes

Block: Noninfective enteritis and colitis (K50-K52)

Excludes 1 (cannot be coded together)

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

Use Additional Code

  • 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)

Subcodes

Subcodes are listed below for reference. Detail pages are not available for chapters 11–22.

Code Description Billable
K51..0 Ulcerative (chronic) pancolitis No
K51..00 Ulcerative (chronic) pancolitis without complications Yes
K51..01 Ulcerative (chronic) pancolitis with complications No
K51..011 Ulcerative (chronic) pancolitis with rectal bleeding Yes
K51..012 Ulcerative (chronic) pancolitis with intestinal obstruction Yes
K51..013 Ulcerative (chronic) pancolitis with fistula Yes
K51..014 Ulcerative (chronic) pancolitis with abscess Yes
K51..018 Ulcerative (chronic) pancolitis with other complication Yes
K51..019 Ulcerative (chronic) pancolitis with unspecified complications Yes
K51..2 Ulcerative (chronic) proctitis No
K51..20 Ulcerative (chronic) proctitis without complications Yes
K51..21 Ulcerative (chronic) proctitis with complications No
K51..211 Ulcerative (chronic) proctitis with rectal bleeding Yes
K51..212 Ulcerative (chronic) proctitis with intestinal obstruction Yes
K51..213 Ulcerative (chronic) proctitis with fistula Yes
K51..214 Ulcerative (chronic) proctitis with abscess Yes
K51..218 Ulcerative (chronic) proctitis with other complication Yes
K51..219 Ulcerative (chronic) proctitis with unspecified complications Yes
K51..3 Ulcerative (chronic) rectosigmoiditis No
K51..30 Ulcerative (chronic) rectosigmoiditis without complications Yes
K51..31 Ulcerative (chronic) rectosigmoiditis with complications No
K51..311 Ulcerative (chronic) rectosigmoiditis with rectal bleeding Yes
K51..312 Ulcerative (chronic) rectosigmoiditis with intestinal obstruction Yes
K51..313 Ulcerative (chronic) rectosigmoiditis with fistula Yes
K51..314 Ulcerative (chronic) rectosigmoiditis with abscess Yes
K51..318 Ulcerative (chronic) rectosigmoiditis with other complication Yes
K51..319 Ulcerative (chronic) rectosigmoiditis with unspecified complications Yes
K51..4 Inflammatory polyps of colon No
K51..40 Inflammatory polyps of colon without complications Yes
K51..41 Inflammatory polyps of colon with complications No
K51..411 Inflammatory polyps of colon with rectal bleeding Yes
K51..412 Inflammatory polyps of colon with intestinal obstruction Yes
K51..413 Inflammatory polyps of colon with fistula Yes
K51..414 Inflammatory polyps of colon with abscess Yes
K51..418 Inflammatory polyps of colon with other complication Yes
K51..419 Inflammatory polyps of colon with unspecified complications Yes
K51..5 Left sided colitis No
K51..50 Left sided colitis without complications Yes
K51..51 Left sided colitis with complications No
K51..511 Left sided colitis with rectal bleeding Yes
K51..512 Left sided colitis with intestinal obstruction Yes
K51..513 Left sided colitis with fistula Yes
K51..514 Left sided colitis with abscess Yes
K51..518 Left sided colitis with other complication Yes
K51..519 Left sided colitis with unspecified complications Yes
K51..8 Other ulcerative colitis No
K51..80 Other ulcerative colitis without complications Yes
K51..81 Other ulcerative colitis with complications No
K51..811 Other ulcerative colitis with rectal bleeding Yes
K51..812 Other ulcerative colitis with intestinal obstruction Yes
K51..813 Other ulcerative colitis with fistula Yes
K51..814 Other ulcerative colitis with abscess Yes
K51..818 Other ulcerative colitis with other complication Yes
K51..819 Other ulcerative colitis with unspecified complications Yes
K51..9 Ulcerative colitis, unspecified No
K51..90 Ulcerative colitis, unspecified, without complications Yes
K51..91 Ulcerative colitis, unspecified, with complications No
K51..911 Ulcerative colitis, unspecified with rectal bleeding Yes
K51..912 Ulcerative colitis, unspecified with intestinal obstruction Yes
K51..913 Ulcerative colitis, unspecified with fistula Yes
K51..914 Ulcerative colitis, unspecified with abscess Yes
K51..918 Ulcerative colitis, unspecified with other complication Yes
K51..919 Ulcerative colitis, unspecified with unspecified complications Yes

Last reviewed: September 2026