ICD-10 Code K58 – Irritable bowel syndrome (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K58 – Irritable bowel syndrome
What it is
K58 identifies irritable bowel syndrome, a functional bowel disorder that causes chronic abdominal discomfort with altered bowel habits. It is used when symptoms fit IBS and no structural disease explains them.
Clinical signs
Typical features include recurrent abdominal pain, bloating, and diarrhea, constipation, or both. Clinical features vary; refer to documentation, and ensure the record supports a functional diagnosis rather than an inflammatory or obstructive condition.
When to use this code
Use K58 when the provider documents IBS, including IBS with diarrhea, constipation, or mixed pattern if the record supports the diagnosis. You may code it for outpatient visits, follow-up care, or evaluations where IBS is the primary documented condition.
Confirm that the note distinguishes IBS from other gastrointestinal disorders. If documentation is unclear, check documentation before assigning the code.
Do not use for
Do not use K58 for acute gastroenteritis, inflammatory bowel disease, or bowel obstruction. If the record does not clearly support IBS, check documentation rather than assuming the diagnosis.
Coding tip
Match the code to the provider’s exact IBS wording and documented subtype, if stated.