ICD-10 Code K31 – Other diseases of stomach and duodenum (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K31 – Other diseases of stomach and duodenum
What it is
K31 is a broad ICD-10-CM category for stomach and duodenal disorders that do not fit a more specific code. Use it only when the record supports a qualifying condition and no narrower diagnosis is documented.
Clinical signs
Clinical features vary; refer to documentation. Commonly, records describe upper abdominal symptoms, abnormal endoscopic findings, or a diagnosed non-specific gastric or duodenal disorder.
When to use this code
Use K31 when the provider documents a stomach or duodenal disease that is not otherwise classified and no more specific code applies. It may also fit when the chart names a disorder in this category without enough detail for a specific code. Check documentation for the exact diagnosis before assigning it.
Do not use for
Do not use K31 when the condition has a more specific ICD-10-CM code, such as a defined ulcer, gastritis, or neoplasm. Avoid it for symptoms alone or when the record is too vague to confirm a disease.
Coding tip
Always search for a more specific stomach or duodenal diagnosis first; K31 is a residual category.