Other diseases of stomach and duodenum (K31) ICD-10-CM
The K31 code range covers other diseases of stomach and duodenum with 32 ICD-10-CM diagnosis codes. 26 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
Includes
This note appears immediately under a three character code title to further define, or give examples of, the content of the category.
- functional disorders of stomach
Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
Codes in the K31 Range 32 codes · 26 billable
- K31 Other diseases of stomach and duodenumNon-billable
- K31.0 Acute dilatation of stomach
- K31.1 Adult hypertrophic pyloric stenosis
- K31.2 Hourglass stricture and stenosis of stomach
- K31.3 Pylorospasm, not elsewhere classified
- K31.4 Gastric diverticulum
- K31.5 Obstruction of duodenum
- K31.6 Fistula of stomach and duodenum
- K31.7 Polyp of stomach and duodenum
- K31.8 Other specified diseases of stomach and duodenumNon-billable
- K31.81 Angiodysplasia of stomach and duodenumNon-billable
- K31.811 Angiodysplasia of stomach and duodenum with bleeding
- K31.819 Angiodysplasia of stomach and duodenum without bleeding
- K31.82 Dieulafoy lesion (hemorrhagic) of stomach and duodenum
- K31.83 Achlorhydria
- K31.84 Gastroparesis
- K31.89 Other diseases of stomach and duodenum
- K31.9 Disease of stomach and duodenum, unspecified
- K31.A Gastric intestinal metaplasiaNon-billable
- K31.A0 Gastric intestinal metaplasia, unspecified
- K31.A1 Gastric intestinal metaplasia without dysplasiaNon-billable
- K31.A11 Gastric intestinal metaplasia without dysplasia, involving the antrum
- K31.A12 Gastric intestinal metaplasia without dysplasia, involving the body (corpus)
- K31.A13 Gastric intestinal metaplasia without dysplasia, involving the fundus
- K31.A14 Gastric intestinal metaplasia without dysplasia, involving the cardia
- K31.A15 Gastric intestinal metaplasia without dysplasia, involving multiple sites
- K31.A19 Gastric intestinal metaplasia without dysplasia, unspecified site
- K31.A2 Gastric intestinal metaplasia with dysplasiaNon-billable
- K31.A21 Gastric intestinal metaplasia with low grade dysplasia
- K31.A22 Gastric intestinal metaplasia with high grade dysplasia
- K31.A29 Gastric intestinal metaplasia with dysplasia, unspecified
- K31.B Hypertrophic pyloric stenosis, in childhood New
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the K31 range.
Achlorhydria
A lack of HYDROCHLORIC ACID in GASTRIC JUICE despite stimulation of gastric secretion.
Diverticulum, Stomach
Saccular, outward protrusion of all or a portion of the wall of the STOMACH.
Gastric Antral Vascular Ectasia
A distinct vascular lesion in the PYLORIC ANTRUM that is characterized by tortuous dilated blood vessels (ectasia) radiating outward from the PYLORUS. The vessel pattern resembles the stripes on the surface of a watermelon. This lesion causes both acute and chronic GASTROINTESTINAL HEMORRHAGE.
Gastroparesis
Chronic delayed gastric emptying. Gastroparesis may be caused by motor dysfunction or paralysis of STOMACH muscles or may be associated with other systemic diseases such as DIABETES MELLITUS.
Intestinal Metaplasia of Gastric Mucosa
A morphologic finding indicating the replacement of part of the gastric mucosal epithelium with intestinal-type epithelium. Using immunohistochemical staining, gastric intestinal metaplasia is classified as complete or incomplete. Complete intestinal metaplasia is defined by the decreased expression of gastric mucins and expression of the intestinal mucin MUC2. Incomplete intestinal metaplasia is defined by the co-expression of both gastric mucins and MUC2.
Pyloric Stenosis, Hypertrophic
Narrowing of the pyloric canal due to HYPERTROPHY of the surrounding circular muscle. It is usually seen in infants or young children.
Pylorospasm
Involuntary spasms of the pylorus.
About the K31 Code Range
These conditions affect the stomach or duodenum and include dilation, narrowing, obstruction, polyps, and other specified diseases.
K31 separates conditions such as acute stomach dilation, adult pyloric stenosis, duodenal obstruction, and stomach or duodenal polyps. K31.8 groups other specified diseases. Within it, angiodysplasia separates into K31.811 with bleeding and K31.819 without bleeding.
K31.A covers gastric intestinal metaplasia. Its subdivisions distinguish whether dysplasia is present, then identify the stomach site or dysplasia grade. K31.B identifies hypertrophic pyloric stenosis in childhood, apart from the adult condition.
FY 2027 changes: The FY 2027 ICD-10-CM update, effective October 1, 2026, added K31.B.
Questions About This Page
How many billable codes are in the K31 range?
Of the 32 codes in this range, 26 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the K31 range classify?
The range classifies other diseases of stomach and duodenum. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
