2026 ICD-10-CM Diagnosis Code K51.511Left sided colitis with rectal bleeding

ICD-10-CM Codes›K00–K95›K50-K52›K51

ICD-10-CM K51.511
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K51.511 is a billable ICD-10-CM diagnosis code for left sided colitis with rectal bleeding. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 385 through 387. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Gastrointestinal hemorrhage and Regional enteritis and ulcerative colitis.

Code Identity

ICD-10-CM Code
K51.511
Billable Status
Yes — Valid for Submission
Code Describes
Left sided colitis with rectal bleeding
Short Description
Left sided colitis with rectal bleeding
Same as the full description in the CMS dataset.
Parent Code
K51.51
Left sided colitis with complications

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK50-K52Noninfective enteritis and colitis
CategoryK51Ulcerative colitis
This CodeK51.511Left sided colitis with rectal bleeding

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Colitis(acute) (catarrhal) (chronic) (noninfective) (hemorrhagic)
      • left sided
        • with
          • rectal bleeding

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR DIG021
Gastrointestinal hemorrhage
Default principal diagnosis: inpatient No · outpatient No
CCSR DIG011
Regional enteritis and ulcerative colitis
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Gastrointestinal Bleeding

Your digestive or gastrointestinal (GI) tract includes the esophagus, stomach, small intestine, large intestine or colon, rectum, and anus. Bleeding can come from any of these areas. The amount of bleeding can be so small that only a lab test can find it.

Read the full article at MedlinePlus

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

Convert K51.511 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
556.5 Lftsded ulcertve colitis
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About K51.511Overview

Is K51.511 (Left sided colitis with complications) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report left sided colitis with rectal bleeding on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does K51.511 group to?

When left sided colitis with rectal bleeding is the principal diagnosis on an inpatient stay, it groups to MS-DRG 385, 386, 387, with relative weights from 0.6813 to 1.5823 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of K51.511?

Under the General Equivalence Mappings, left sided colitis with rectal bleeding converts to ICD-9-CM 556.5 (lftsded ulcertve colitis). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.