K59.1

Billable
ChapterK00–K95
Ranksubcategory
Official Description

Functional diarrhea

Metadata & Insights
  • •2026 ICD-10-CM Edition - Effective October 1, 2025.
  • •Billable/specific code (valid for reimbursement).
  • •Chapter 11: Diseases of the Digestive System (K00-K95).

Instructional Notes

Excludes1(Not coded here)
  • diarrhea NOS (R19.7)
  • irritable bowel syndrome with diarrhea (K58.0)
General instructions are available for the parent sections:
View CH11 NotesView K59 Notes

Clinical Hierarchy

CH11Diseases of the digestive system (K00-K95)
K55-K64Other diseases of intestines (K55-K64)
K59Other functional intestinal disorders
K59.1Functional diarrhea

Applicable Ancestor Context

The following parent sections contain instructions or notes that apply to K59.1:

categoryK59
Other functional intestinal disorders
View context instructions
chapterCH11
Diseases of the digestive system (K00-K95)
View context instructions

Alphabetic Index Mentions

These are Diagnosis Index lookup paths that route to K59.1. Use them as entry terms for search, then confirm final coding instructions in the Tabular List and notes above.

2 raw paths
Diarrhea, diarrheal (disease) (infantile) (inflammatory)2 unique routes
functional→K59.1
neurogenic→K59.1

MS-DRG Classification

2026 v43.1

This code is grouped within the following Diagnosis Related Group(s) for clinical reimbursement:

DRG 391
Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders with MCC
DRG 392
Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders without MCC

Cross Reference

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