2026 ICD-10-CM Diagnosis Code K58.1Irritable bowel syndrome with constipation

ICD-10-CM Codes›K00–K95›K55-K64›K58

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

K58.1 is a billable ICD-10-CM diagnosis code for irritable bowel syndrome with constipation. 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified gastrointestinal disorders.

Code Identity

ICD-10-CM Code
K58.1
Billable Status
Yes — Valid for Submission
Code Describes
Irritable bowel syndrome with constipation
Short Description
Irritable bowel syndrome with constipation
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 CodeK58.1Irritable bowel syndrome with constipation

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.

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 K58.1 to ICD-9-CMHistory

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

ICD-9-CM
564.1 Irritable bowel syndrome
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.
ICD-9-CM
564.09 Constipation NEC
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.

Code History & ChangesHistory

Replacement K58.1 replaces the following previously assigned code(s):

  • K58.9 - Irritable bowel syndrome without diarrhea
  • K58.9 - Irritable bowel syndrome, unspecified
  • K59.00 - Constipation, unspecified
FY 2019AddedAdded to the ICD-10-CM code setEffective October 1, 2018.
FY 2020–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About K58.1Overview

What is the ICD-10 code for irritable bowel syndrome with constipation?

The ICD-10-CM code for irritable bowel syndrome with constipation is K58.1 (sometimes written as K581). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is K58.1 (Irritable bowel syndrome) a billable code?

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

What MS-DRG does K58.1 group to?

When irritable bowel syndrome with constipation 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 K58.1?

Under the General Equivalence Mappings, irritable bowel syndrome with constipation converts to ICD-9-CM 564.1 (irritable bowel syndrome) and 564.09 (constipation NEC). The mapping is approximate, so confirm the match fits the documentation.