ICD-10 Code K29.8 – Duodenitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K29.8 – Duodenitis
What it is
Duodenitis means inflammation of the duodenum, the first part of the small intestine. Use this code when documentation identifies duodenal inflammation without a more specific underlying diagnosis.
Clinical signs
Clinical features vary; refer to documentation. Commonly recorded findings include upper abdominal discomfort, nausea, or endoscopic evidence of duodenal inflammation.
When to use this code
Use K29.8 when the provider documents duodenitis as the final diagnosis, including cases found on endoscopy or imaging. Code it when the record does not specify a different cause or more detailed duodenal condition. If the note links the inflammation to another confirmed disorder, follow that documentation instead.
Do not use for
Do not use this code for gastritis alone or for peptic ulcer disease unless duodenitis is clearly documented. Check documentation if the inflammation is part of a different primary gastrointestinal diagnosis.
Coding tip
Verify whether the provider described isolated duodenitis or a broader gastroduodenal condition before assigning K29.8.