2026 ICD-10-CM Diagnosis Code K59Other functional intestinal disorders

ICD-10-CM Codes›K00–K95›K55-K64›K59

ICD-10-CM K59
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K59 is a non-billable ICD-10-CM category code for other functional intestinal disorders, so it cannot be submitted on claims. Use a more specific code from this category instead, such as K59.00, K59.01, K59.02, and K59.03.

Code Identity

ICD-10-CM Code
K59
Billable Status
No — Non-Billable Category
Code Describes
Other functional intestinal disorders
Chapter
K55-K64
Other diseases of intestines

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK55-K64Other diseases of intestines
CategoryK59Other functional intestinal disorders
This CodeK59Other functional intestinal disorders

Specific Coding for Other functional intestinal disordersOverview

Non-specific codes like K59 require more characters. Use one of these billable codes instead:

  • K59.0 for Constipation

  • Use K59.00 for Constipation, unspecified

  • Use K59.01 for Slow transit constipation

  • Use K59.02 for Outlet dysfunction constipation

  • Use K59.03 for Drug induced constipation

  • Use K59.04 for Chronic idiopathic constipation

  • Use K59.09 for Other constipation

  • Use K59.1 for Functional diarrhea

  • Use K59.2 for Neurogenic bowel, not elsewhere classified

  • K59.3 for Megacolon, not elsewhere classified

  • Use K59.31 for Toxic megacolon

  • Use K59.39 for Other megacolon

  • Use K59.4 for Anal spasm

  • K59.8 for Other specified functional intestinal disorders

  • Use K59.81 for Ogilvie syndrome

  • Use K59.89 for Other specified functional intestinal disorders

  • Use K59.9 for Functional intestinal disorder, unspecified

Tabular List NotesGuidance

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

Type 1 Excludes

  • change in bowel habit NOS R19.4
  • intestinal malabsorption K90
  • psychogenic intestinal disorders F45.8

Type 2 Excludes

  • functional disorders of stomach K31

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.

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 K59Overview

Is K59 (Other functional intestinal disorders) a billable code?

No. This is a category header that groups the codes for other functional intestinal disorders, and headers cannot be submitted on claims. Claims for other functional intestinal disorders need a more specific code from this category, such as K59.00, K59.01, and K59.02.