2026 ICD-10-CM Diagnosis Code K55.019Acute (reversible) ischemia of small intestine, extent unspecified

ICD-10-CM Codes›K00–K95›K55-K64›K55

ICD-10-CM K55.019
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K55.019 is a billable ICD-10-CM diagnosis code for acute (reversible) ischemia of small intestine, extent 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. Coders also document this condition as acute GIT vascular insufficiency. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified gastrointestinal disorders and Peripheral and visceral vascular disease.

Code Identity

ICD-10-CM Code
K55.019
Billable Status
Yes — Valid for Submission
Code Describes
Acute (reversible) ischemia of small intestine, extent unspecified
Short Description
Acute ischemia of small intestine, extent unspecified
Parent Code
K55.01
Acute (reversible) ischemia of small intestine

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK55-K64Other diseases of intestines
CategoryK55Vascular disorders of intestine
This CodeK55.019Acute (reversible) ischemia of small intestine, extent unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute GIT vascular insufficiency
  • Acute ischemia of small intestine due to thrombosis of mesenteric vein
  • Acute thrombosis of mesenteric vein
  • Acute vascular insufficiency of intestine
  • Acute visceral ischemia
  • Thrombosis of mesenteric vein
  • Visceral ischemia

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.

    • Enteritis(acute) (diarrheal) (hemorrhagic) (noninfective)
      • fulminant
    • Enteritis(acute) (diarrheal) (hemorrhagic) (noninfective)
      • ischemic
        • acute
    • Ischemia, ischemic
      • intestine (large) (small) (transient)
        • acute
          • small
    • Ischemia, ischemic
      • small bowel
        • acute

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
CCSR CIR026
Peripheral and visceral vascular disease
Default principal diagnosis: inpatient No · outpatient No

Convert K55.019 to ICD-9-CMHistory

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

ICD-9-CM
557.0 Ac vasc insuff intestine
Approximate The match is approximate rather than exact.

Code History & ChangesHistory

Replacement K55.019 replaces the following previously assigned code(s):

  • K55.0 - Acute vascular disorders of intestine
FY 2018AddedAdded to the ICD-10-CM code setEffective October 1, 2017.
FY 2019–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About K55.019Overview

Is K55.019 (Acute (reversible) ischemia of small intestine) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report acute (reversible) ischemia of small intestine, extent unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does K55.019 group to?

When acute (reversible) ischemia of small intestine, extent 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 K55.019?

Under the General Equivalence Mappings, acute (reversible) ischemia of small intestine, extent unspecified converts to ICD-9-CM 557.0 (ac vasc insuff intestine). 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.