ICD-10-CM Code K59.1
Functional diarrhea
Diagnosis information
Billable
Yes
Valid for claim submission
Chapter
K00–K95
Diseases of the digestive system
Risk adjustment
None
Not risk-adjustable (V28)
More codes in the K59 category
Other billable ICD-10-CM codes in the same category as K59.1. Coding to the highest specificity the documentation supports is what keeps a claim clean — pick the child code that most precisely matches the diagnosis.
- K59.00Constipation, unspecified
- K59.01Slow transit constipation
- K59.02Outlet dysfunction constipation
- K59.03Drug induced constipation
- K59.04Chronic idiopathic constipation
- K59.09Other constipation
- K59.2Neurogenic bowel, not elsewhere classified
- K59.31Toxic megacolon
- K59.39Other megacolon
- K59.4Anal spasm
- K59.81Ogilvie syndrome
- K59.89Other specified functional intestinal disorders
Documentation & coding notes
- K59.1 is a billable/specific ICD-10-CM code — it can be reported as a primary or secondary diagnosis when the documentation supports it. Code to the highest level of specificity the record allows.
- Always verify the code against the current ICD-10-CM Official Guidelines and the payer's coverage policy before submitting — coverage, medical necessity edits, and sequencing rules vary by payer.
Related K00–K95 codes
Questions about coding K59.1?
Ask D3 — free AI backed by CMS, ICD-10-CM, and major-payer data. Get a cited answer in seconds, no signup.
Medical coding disclaimer
ICD-10-CM codes and descriptions shown are from the CMS FY2026 official code set and HCC mappings from the CMS-HCC V28 model (payment year 2026), shown for educational reference. Official Guidelines, payer coverage, medical-necessity edits, and sequencing rules vary. Always verify with the current ICD-10-CM Official Guidelines and the payer before submitting claims. D3rx is not responsible for coding or billing outcomes.