ICD-10 Code K58.0 – Irritable bowel syndrome with diarrhea (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K58.0 – Irritable bowel syndrome with diarrhea
What it is
K58.0 identifies irritable bowel syndrome when diarrhea is the predominant bowel pattern. It is a functional gastrointestinal disorder, meaning symptoms occur without a structural cause documented in routine evaluation.
Clinical signs
Typical features include recurrent abdominal pain linked with loose stools, urgency, and relief or change in pain after bowel movements. Clinical features vary; refer to documentation.
When to use this code
Use K58.0 when the provider documents IBS with diarrhea, diarrhea-predominant IBS, or a similar equivalent term. Code it only when the record supports IBS and diarrhea as the dominant symptom pattern. If the note does not clearly specify the subtype, check documentation.
Do not use for
Do not use this code for infectious diarrhea, inflammatory bowel disease, or nonspecific abdominal pain without an IBS diagnosis. Do not assume IBS-D if the chart only says “IBS” without a diarrhea-predominant description.
Coding tip
Match the code to the provider’s exact IBS subtype wording and avoid defaulting to K58.0 unless diarrhea is clearly documented.