ICD-10 Code K58.8 – Other irritable bowel syndrome (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K58.8 – Other irritable bowel syndrome
What it is
K58.8 identifies irritable bowel syndrome that does not fit the more specific IBS subtypes. Use it for a functional bowel disorder with recurrent abdominal discomfort and altered bowel habits when documentation supports IBS but not diarrhea-predominant, constipation-predominant, or mixed type.
Clinical signs
Clinical features vary; refer to documentation. Typical IBS findings include recurrent abdominal pain linked to bowel movements and changes in stool frequency or form, without evidence of structural disease.
When to use this code
Use K58.8 when the clinician documents IBS and specifies another or unspecified IBS type that is not captured by the more common subcategories. It also fits cases where the record clearly supports IBS but does not state the bowel-pattern subtype. Review the note carefully for any laterality or excluded diagnosis.
Do not use for
Do not use this code for constipation, diarrhea, or abdominal pain alone without a documented IBS diagnosis. If the chart identifies a specific IBS subtype, code that more precise option instead.
Coding tip
Code from the provider’s exact IBS wording, and query if the subtype is missing or unclear.