2026 ICD-10-CM Diagnosis Code K55.21Angiodysplasia of colon with hemorrhage

ICD-10-CM Codes›K00–K95›K55-K64›K55

ICD-10-CM K55.21
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K55.21 is a billable ICD-10-CM diagnosis code for angiodysplasia of colon with hemorrhage. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 377 through 379. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. It does not count, however, when the principal diagnosis is one of 72 closely related codes. Coders also document this condition as angiodysplasia of colon. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Gastrointestinal hemorrhage, Other specified and unspecified gastrointestinal disorders, and Peripheral and visceral vascular disease.

Code Identity

ICD-10-CM Code
K55.21
Billable Status
Yes — Valid for Submission
Code Describes
Angiodysplasia of colon with hemorrhage
Short Description
Angiodysplasia of colon with hemorrhage
Same as the full description in the CMS dataset.
Parent Code
K55.2
Angiodysplasia of colon

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK55-K64Other diseases of intestines
CategoryK55Vascular disorders of intestine
This CodeK55.21Angiodysplasia of colon with hemorrhage

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Angiodysplasia of colon
  • Angiodysplasia of gastrointestinal tract
  • Angiodysplasia of intestine
  • Angiodysplasia of large intestine
  • Hemorrhage of colon
  • Hemorrhage of colon due to angiodysplasia of colon
  • Intestinal hemorrhage due to angiodysplasia of intestine
  • Vascular disorder of large intestine

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

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

CCSR DIG021
Gastrointestinal hemorrhage
Default principal diagnosis: inpatient No · outpatient No
CCSR DIG025
Other specified and unspecified gastrointestinal disorders
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR CIR026
Peripheral and visceral vascular disease
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Colonic Diseases

Your colon, also known as the large intestine, is part of your digestive system. It's a long, hollow tube at the end of your digestive tract where your body makes and stores stool. Many disorders affect the colon's ability to work properly. Some of these include:

Read the full article at MedlinePlus

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

Convert K55.21 to ICD-9-CMHistory

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

ICD-9-CM
569.85 Angio intes w hmrhg
Exact Match The mapping is direct, with no qualifiers.

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 K55.21Overview

What is the ICD-10 code for angiodysplasia of colon with hemorrhage?

The ICD-10-CM code for angiodysplasia of colon with hemorrhage is K55.21 (sometimes written as K5521). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is K55.21 (Angiodysplasia of colon) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report angiodysplasia of colon with hemorrhage on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does K55.21 group to?

When angiodysplasia of colon with hemorrhage is the principal diagnosis on an inpatient stay, it groups to MS-DRG 377, 378, 379, with relative weights from 0.6304 to 1.8280 depending on complications. Higher weights mean higher Medicare reimbursement.

Is K55.21 a CC or MCC?

CMS lists K55.21 as an MCC (major complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It does not count when the principal diagnosis is one of the 72 closely related codes in its exclusion list.

What is the ICD-9 equivalent of K55.21?

Under the General Equivalence Mappings, angiodysplasia of colon with hemorrhage converts to ICD-9-CM 569.85 (angio intes w hmrhg). The mapping is a direct match.