2026 ICD-10-CM Diagnosis Code K55.9Vascular disorder of intestine, unspecified

ICD-10-CM Codes›K00–K95›K55-K64›K55

ICD-10-CM K55.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K55.9 is a billable ICD-10-CM diagnosis code for vascular disorder of intestine, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 393 through 395. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified gastrointestinal disorders.

Code Identity

ICD-10-CM Code
K55.9
Billable Status
Yes — Valid for Submission
Code Describes
Vascular disorder of intestine, unspecified
Short Description
Vascular disorder of intestine, unspecified
Same as the full description in the CMS dataset.
Parent Code
K55
Vascular disorders of intestine

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK55-K64Other diseases of intestines
CategoryK55Vascular disorders of intestine
This CodeK55.9Vascular disorder of intestine, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute diffuse ischemic enteritis
  • Acute diffuse ischemic enterocolitis
  • Acute GIT vascular insufficiency
  • Acute ischemic colitis
  • Acute ischemic enteritis
  • Acute ischemic enterocolitis
  • Acute vascular insufficiency of intestine
  • Alimentary tract pain due to vascular insufficiency
  • Disorder of vascular structure of duodenum
  • Focal segmental ischemia of small intestine
  • Ischemia of colostomy
  • Ischemia of stoma
  • Ischemic colitis
  • Ischemic enteritis of intestine
  • Ischemic enterocolitis
  • Ischemic gastroenteritis
  • Nongangrenous ischemic colitis
  • Noninfective enteritis and colitis
  • Vascular disorder of intestine
  • Vascular disorder of large intestine
  • Vascular disorder of small intestine
  • Vascular insufficiency of intestine

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Ischemic colitis
  • Ischemic enteritis
  • Ischemic enterocolitis

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)
      • ischemic
    • Disorder(of)
      • intestine, intestinal
        • vascular
    • Enteritis(acute) (diarrheal) (hemorrhagic) (noninfective)
      • ischemic
    • Enterocolitis
      • ischemic
    • Insufficiency, insufficient
      • vascular
        • intestine
    • Ischemia, ischemic
      • intestine (large) (small) (transient)
    • Syndrome
      • ischemic
        • bowel (transient)

Clinical ClassificationClinical

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

CCSR DIG025
Other specified and unspecified gastrointestinal disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Digestive Diseases

When you eat, your body breaks food down to a form it can use to build and nourish cells and provide energy. This process is called digestion.

Read the full article at MedlinePlus

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

Convert K55.9 to ICD-9-CMHistory

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

ICD-9-CM
557.9 Vasc insuff intest NOS
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 K55.9Overview

Is K55.9 (Vascular disorders of intestine) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report vascular disorder of intestine, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does K55.9 group to?

When vascular disorder of intestine, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 393, 394, 395, with relative weights from 0.6490 to 1.5993 depending on complications. Higher weights mean higher Medicare reimbursement.

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

Under the General Equivalence Mappings, vascular disorder of intestine, unspecified converts to ICD-9-CM 557.9 (vasc insuff intest NOS). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.