K59.8 Other specified functional intestinal disorders

The ICD-10-CM code for Other specified functional intestinal disorders is K59.8 (FY2026). It is a non-billable category code — select a more specific code below for claims.

Classification

Chapter

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

Section

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

Category K59

18 codes (14 billable)

FY2026 Status

Stable since FY2024

U.S. Hospital Utilization

• An estimated 7,665 U.S. inpatient stays in 2020 included K59.8 among the documented diagnoses.
• 1,975 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)