ICD-10 Code K63.8219 – Small intestinal bacterial overgrowth, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K63.8219 – Small intestinal bacterial overgrowth, unspecified
What it is
K63.8219 identifies small intestinal bacterial overgrowth when the record does not specify the cause or type. Use it for documented SIBO without a more detailed code option.
Clinical signs
Clinical features vary; refer to documentation. Commonly recorded findings include bloating, abdominal discomfort, gas, diarrhea, or malabsorption-related symptoms, but the diagnosis should be supported by the provider.
When to use this code
Use this code when the clinician documents small intestinal bacterial overgrowth and does not specify an underlying cause, such as an anatomic abnormality or other listed condition. It also fits when the note states SIBO or bacterial overgrowth of the small bowel without further detail.
If the chart includes a more specific etiology or subtype, code that documentation instead of this unspecified option. Check documentation when the wording is vague or abbreviated.
Do not use for
Do not use this code for generalized gastrointestinal symptoms without a documented diagnosis of SIBO. Do not assign it when the record supports a more specific small intestinal bacterial overgrowth code.
Coding tip
Query the provider if the note says “SIBO” but does not clarify whether it is unspecified or linked to a documented cause.