ICD-10 Code K58.2 – Mixed irritable bowel syndrome (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K58.2 – Mixed irritable bowel syndrome
What it is
K58.2 identifies mixed irritable bowel syndrome, a functional bowel disorder with both constipation and diarrhea patterns. Use it when the chart documents alternating bowel habits without another clear organic cause.
Clinical signs
Clinical features vary; refer to documentation. Commonly recorded findings include recurrent abdominal pain with alternating loose stools and constipation, bloating, and symptom fluctuation over time.
When to use this code
Use K58.2 when the provider documents IBS with mixed bowel habits or alternating constipation and diarrhea. The diagnosis should be supported by the record, such as a stated clinical assessment or prior confirmed IBS history. If the note only says “IBS,” check documentation for the subtype.
Do not use for
Do not use this code for constipation-only or diarrhea-only IBS, or for bowel symptoms caused by infection, inflammatory bowel disease, or other identified gastrointestinal disorders. Check documentation if the cause is unclear.
Coding tip
Code the documented IBS subtype exactly; if mixed pattern is not stated, verify the provider’s assessment before assigning K58.2.