ICD-10 Code K31.9 – Disease of stomach and duodenum, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K31.9 – Disease of stomach and duodenum, unspecified
What it is
K31.9 is a nonspecific diagnosis for a disorder of the stomach or duodenum when the provider documents a disease but does not name a more exact condition. Use it when the record supports upper gastrointestinal disease, but details are incomplete.
Clinical signs
Clinical features vary; refer to documentation. Commonly, records may note epigastric pain, dyspepsia, nausea, bloating, or other upper abdominal complaints without a definitive labeled diagnosis.
When to use this code
Use K31.9 when the clinician documents a stomach or duodenal disorder but does not specify the exact disease, such as when the note says “gastric disorder” or “duodenal disease” without further detail. It also fits when available documentation confirms the site, but not the precise condition. If the provider later identifies a more specific disorder, update the code.
Do not use for
Do not use K31.9 if the chart identifies a specific condition, such as gastritis, ulcer disease, or functional dyspepsia. Also avoid it when the complaint is only a symptom and no stomach or duodenal disease is documented.
Coding tip
Query for specificity whenever the note is vague, because K31.9 is appropriate only when the documentation supports a gastric or duodenal disease without further detail.