2027 ICD-10-CM Diagnosis Code K51Ulcerative colitis

ICD-10-CM Codes›K00–K95›K50-K52›K51

ICD-10-CM K51
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

K51 is a non-billable ICD-10-CM category code for ulcerative colitis, so it cannot be submitted on claims. Use a more specific code from this category instead, such as K51.00, K51.011, K51.012, and K51.013.

Code Identity

ICD-10-CM Code
K51
Billable Status
No — Non-Billable Category
Code Describes
Ulcerative colitis
Short Description
Ulcerative colitis
Same as the full description in the CMS dataset.
Chapter
K50-K52
Noninfective enteritis and colitis

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK50-K52Noninfective enteritis and colitis
CategoryK51Ulcerative colitis
This CodeK51Ulcerative colitis

Specific Coding for Ulcerative colitisOverview

Non-specific codes like K51 require more characters. Use one of these billable codes instead:

  • K51.0 for Ulcerative (chronic) pancolitis

  • Use K51.00 for Ulcerative (chronic) pancolitis without complications

  • K51.01 for Ulcerative (chronic) pancolitis with complications

  • K51.2 for Ulcerative (chronic) proctitis

  • Use K51.20 for Ulcerative (chronic) proctitis without complications

  • K51.21 for Ulcerative (chronic) proctitis with complications

  • K51.3 for Ulcerative (chronic) rectosigmoiditis

  • Use K51.30 for Ulcerative (chronic) rectosigmoiditis without complications

  • K51.31 for Ulcerative (chronic) rectosigmoiditis with complications

  • K51.4 for Inflammatory polyps of colon

  • Use K51.40 for Inflammatory polyps of colon without complications

  • K51.41 for Inflammatory polyps of colon with complications

  • K51.5 for Left sided colitis

  • Use K51.50 for Left sided colitis without complications

  • K51.51 for Left sided colitis with complications

  • K51.8 for Other ulcerative colitis

  • Use K51.80 for Other ulcerative colitis without complications

  • K51.81 for Other ulcerative colitis with complications

  • K51.9 for Ulcerative colitis, unspecified

  • Use K51.90 for Ulcerative colitis, unspecified, without complications

  • K51.91 for Ulcerative colitis, unspecified, with complications

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to K51: its own notes plus those printed at block K50-K52 and Chapter 11. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Block K50-K52 Noninfective enteritis and colitis applies to 91 codes
  • noninfective inflammatory bowel disease

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

On K51 itself
  • Crohn's disease [regional enteritis] (K50.-)
From Block K50-K52 Noninfective enteritis and colitis applies to 91 codes

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 11 (K00-K95) Diseases of the digestive system applies to 863 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

  • 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)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name K51, its category, or a range that includes it.

Excludes1 3

These codes carry an Excludes1 note naming K51: they are not reported together with it, unless the two conditions are unrelated.

  • K50 Crohn's disease [regional enteritis]
    ulcerative colitis (K51.-)
  • K62.6 Ulcer of anus and rectum
    ulcerative colitis (K51.-)
  • K63.3 Ulcer of intestine
    ulcerative colitis (K51.-)

Code First 4

These codes say to code first a condition named in the note, and K51 is one of the conditions named.

  • F54 Psychological and behavioral factors associated with disorders or diseases classified elsewhere
    ulcerative colitis (K51.-)
  • K60.3 Anal fistula
    ulcerative colitis (K51.-)
  • K60.4 Rectal fistula
    ulcerative colitis (K51.-)
  • K60.5 Anorectal fistula
    ulcerative colitis (K51.-)

Code Also 2

These codes say K51 may also be needed to fully describe the condition. The note gives no sequencing direction.

  • M07 Enteropathic arthropathies
    ulcerative colitis (K51.-)
  • M08 Juvenile arthritis
    ulcerative colitis (K51.-)

Clinical InformationClinical

  • Colitis, Ulcerative

    inflammation of the colon that is predominantly confined to the mucosa. its major symptoms include diarrhea, rectal bleeding, the passage of mucus, and abdominal pain.

Patient EducationClinical

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 the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About K51Overview

What is the ICD-10 code for ulcerative colitis?

K51 is the ICD-10-CM category for ulcerative colitis, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is K51 (Ulcerative colitis) a billable code?

No. This is a category header that groups the codes for ulcerative colitis, and headers cannot be submitted on claims. Claims for ulcerative colitis need a more specific code from this category, such as K51.00, K51.011, and K51.012.

Can K51 be reported with a code from K50?

Not as a rule. The Excludes1 note on K51 lists "Crohn's disease [regional enteritis] (K50.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

Does K51 need an additional code?

When the condition applies, yes. The Use Additional Code note reads: 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). The additional code is reported after K51.