K58.9 Irritable bowel syndrome, unspecified

The ICD-10-CM code for Irritable bowel syndrome, unspecified is K58.9 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

11: Diseases of the digestive system (K00-K95)

Section

K55-K64: Other diseases of intestines (K55-K64)

Category K58

6 codes (5 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to K58.9:

• Irritable, irritability › bowel (syndrome)
• Irritable, irritability › colon
• Spasm (s), spastic, spasticity › colon
• Colitis (acute) (catarrhal) (chronic) (noninfective) (hemorrhagic) › spastic
• Irritable, irritability › without diarrhea
• Hypermobility, hypermotility › ileum
• Hypermobility, hypermotility › intestine
• Colic (bilious) (infantile) (intestinal) (recurrent) (spasmodic) › mucous

Inclusion Terms

• Irritable bowel syndrome NOS

U.S. Hospital Utilization

• An estimated 193,180 U.S. inpatient stays in 2023 included K58.9 among the documented diagnoses.
• 1,225 stays listed it as the principal diagnosis.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Official Coding Guidelines

Chapter 11 reserved for future expansion

11. Chapter 11: Diseases of the Digestive System (K00-K95) Reserved for future guideline expansion

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)