2026 ICD-10-CM Diagnosis Code K58.9Irritable bowel syndrome, unspecified

ICD-10-CM Codes›K00–K95›K55-K64›K58

ICD-10-CM K58.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K58.9 is a billable ICD-10-CM diagnosis code for irritable bowel syndrome, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 391 through 392. Coders also document this condition as bowel spasm. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified gastrointestinal disorders.

Code Identity

ICD-10-CM Code
K58.9
Billable Status
Yes — Valid for Submission
Code Describes
Irritable bowel syndrome, unspecified
Short Description
Irritable bowel syndrome, unspecified
Same as the full description in the CMS dataset.
Parent Code
K58
Irritable bowel syndrome

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK55-K64Other diseases of intestines
CategoryK58Irritable bowel syndrome
This CodeK58.9Irritable bowel syndrome, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bowel spasm
  • Colonospasm
  • Enterospasm
  • Irritable bowel syndrome
  • Irritable bowel syndrome characterized by alternating bowel habit
  • Irritable bowel syndrome characterized by constipation
  • Irritable bowel syndrome variant of childhood
  • Irritable bowel syndrome variant of childhood with constipation

Tabular List NotesGuidance

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

Inclusion Terms

  • Irritable bowel syndrome NOS

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

Clinical InformationClinical

  • Irritable Bowel Syndrome

    a disorder with chronic or recurrent colonic symptoms without a clearcut etiology. this condition is characterized by chronic or recurrent abdominal pain, bloating, mucus in feces, and an erratic disturbance of defecation.

  • Colonospasm

    sudden, involuntary contraction of the smooth muscles of the colon.

Patient EducationClinical

Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a problem that affects the large intestine. It can cause abdominal cramping, bloating, and a change in bowel habits. Some people with the disorder have constipation. Some have diarrhea. Others go back and forth between the two.

Read the full article at MedlinePlus

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

Convert K58.9 to ICD-9-CMHistory

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

ICD-9-CM
564.1 Irritable bowel syndrome
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 2017–2024No changes
FY 2025RevisedCode revised
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About K58.9Overview

What is the ICD-10 code for irritable bowel syndrome, unspecified?

The ICD-10-CM code for irritable bowel syndrome, unspecified is K58.9 (sometimes written as K589). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is K58.9 (Irritable bowel syndrome) a billable code?

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

What MS-DRG does K58.9 group to?

When irritable bowel syndrome, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 391, 392, with relative weights from 0.7796 to 1.2683 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of K58.9?

Under the General Equivalence Mappings, irritable bowel syndrome, unspecified converts to ICD-9-CM 564.1 (irritable bowel syndrome). The mapping is approximate, so confirm the match fits the documentation.