DxCodebookFY2027 · Oct 1, 2026 – Sep 30, 2027

Category · FY2027

K31 Other diseases of stomach and duodenum

  • Header · not billable

K31 is not billable. The category heads 26 billable codes in FY2027, grouped under 12 subdivisions.

FY2027 changes under K31: 1 billable code added. All FY2027 changes.

Index → code

Where it sits

  1. Chapter 11 Diseases of the digestive system (K00-K95)
  2. K20-K31 Diseases of esophagus, stomach and duodenum (K20-K31)
  3. K31 Other diseases of stomach and duodenum
Billable codes
26
Subdivisions
12
CC / MCC codes
5 / 2
HCC V28 codes
0
New FY2027
1
Index entries
175

Codes in K31

  1. K31.0
    Acute dilatation of stomach
    BillableCC
    Inclusion terms 1

    Inclusion terms

    • Acute distention of stomach
  2. K31.1
    Adult hypertrophic pyloric stenosis
    BillableCC
    Inclusion terms 3, Excludes1 1

    Inclusion terms

    • Acquired hypertrophic pyloric stenosis
    • Adult pyloric stenosis
    • Pyloric stenosis NOS

    Excludes1

    • congenital pyloric stenosis (Q40.0) Q40.0
  3. K31.B
    Hypertrophic pyloric stenosis, in childhood New FY2027
    BillableCC
    Inclusion terms 3, Excludes1 1

    Inclusion terms

    • Infantile hypertrophic pyloric stenosis
    • Pediatric hypertrophic pyloric stenosis
    • Pediatric pyloric stenosis

    Excludes1

    • congenital pyloric stenosis (Q40.0) Q40.0
  4. K31.2
    Hourglass stricture and stenosis of stomach
    Billable
    Excludes1 2

    Excludes1

    • congenital hourglass stomach (Q40.2) Q40.2
    • hourglass contraction of stomach (K31.89) K31.89
  5. K31.3
    Pylorospasm, not elsewhere classified
    Billable
    Excludes1 3

    Excludes1

    • congenital or infantile pylorospasm (Q40.0) Q40.0
    • neurotic pylorospasm (F45.8) F45.8
    • psychogenic pylorospasm (F45.8) F45.8
  6. K31.4
    Gastric diverticulum
    Billable
    Excludes1 1

    Excludes1

    • congenital diverticulum of stomach (Q40.2) Q40.2
  7. K31.5
    Obstruction of duodenum
    BillableCC
    Inclusion terms 5, Excludes1 1

    Inclusion terms

    • Constriction of duodenum
    • Duodenal ileus (chronic)
    • Stenosis of duodenum
    • Stricture of duodenum
    • Volvulus of duodenum

    Excludes1

    • congenital stenosis of duodenum (Q41.0) Q41.0
  8. K31.6
    Fistula of stomach and duodenum
    BillableCC
    Inclusion terms 2, Code also 1

    Inclusion terms

    • Gastrocolic fistula
    • Gastrojejunocolic fistula

    Code also

    • , if applicable, disruption of internal operation (surgical) wound (T81.32-) T81.32
  9. K31.7
    Polyp of stomach and duodenum
    Billable
    Excludes1 1

    Excludes1

    • adenomatous polyp of stomach (D13.1) D13.1
  10. K31.8
    Other specified diseases of stomach and duodenum
    Header
  11. K31.81
    Angiodysplasia of stomach and duodenum
    Header
  12. K31.811
    Angiodysplasia of stomach and duodenum with bleeding
    BillableMCC
  13. K31.819
    Angiodysplasia of stomach and duodenum without bleeding
    Billable
    Inclusion terms 1

    Inclusion terms

    • Angiodysplasia of stomach and duodenum NOS
  14. K31.82
    Dieulafoy lesion (hemorrhagic) of stomach and duodenum
    BillableMCC
    Excludes2 1

    Excludes2

    • Dieulafoy lesion of intestine (K63.81) K63.81
  15. K31.83
    Achlorhydria
    Billable
  16. K31.84
    Gastroparesis
    Billable
    Inclusion terms 1, Code first 4

    Inclusion terms

    • Gastroparalysis

    Code first

  17. K31.89
    Other diseases of stomach and duodenum
    Billable
  18. K31.9
    Disease of stomach and duodenum, unspecified
    Billable
  19. K31.A
    Gastric intestinal metaplasia
    Header
  20. K31.A0
    Gastric intestinal metaplasia, unspecified
    Billable
    Inclusion terms 2

    Inclusion terms

    • Gastric intestinal metaplasia indefinite for dysplasia
    • Gastric intestinal metaplasia NOS
  21. K31.A1
    Gastric intestinal metaplasia without dysplasia
    Header
  22. K31.A11
    Gastric intestinal metaplasia without dysplasia, involving the antrum
    Billable
  23. K31.A12
    Gastric intestinal metaplasia without dysplasia, involving the body (corpus)
    Billable
  24. K31.A13
    Gastric intestinal metaplasia without dysplasia, involving the fundus
    Billable
  25. K31.A14
    Gastric intestinal metaplasia without dysplasia, involving the cardia
    Billable
  26. K31.A15
    Gastric intestinal metaplasia without dysplasia, involving multiple sites
    Billable
  27. K31.A19
    Gastric intestinal metaplasia without dysplasia, unspecified site
    Billable
  28. K31.A2
    Gastric intestinal metaplasia with dysplasia
    Header
  29. K31.A21
    Gastric intestinal metaplasia with low grade dysplasia
    Billable
  30. K31.A22
    Gastric intestinal metaplasia with high grade dysplasia
    Billable
  31. K31.A29
    Gastric intestinal metaplasia with dysplasia, unspecified
    Billable

CC/MCC: as a secondary diagnosis, unless the principal diagnosis is on the code’s PDX exclusion list (MS-DRG v44 Appendix C; list on the code card).

Sources of each column.

Instructions

At K31

Includes

  • functional disorders of stomach

Excludes2

Notes that also apply

Block K20-K31 instructions (Excludes2 1): printed on the block page.

Chapter 11 instructions (Excludes2 8): printed on the chapter 11 page.

Index entries

  • Gastrectasis → K31.0
  • Bilocular stomach → K31.2
  • Cascade stomach → K31.2
  • Pylorospasm (reflex) NEC → K31.3
  • Watermelon stomach → K31.819
  • Achlorhydria, achlorhydric (neurogenic) → K31.83
  • Anacidity, gastric → K31.83
  • Gastroparalysis → K31.84
  • Gastroparesis → K31.84
  • Achylia gastrica → K31.89
  • Fish hook stomach → K31.89
  • Gastroliths → K31.89
  • Gastromalacia → K31.89
  • Gastroptosis → K31.89
  • Gastrospasm (neurogenic) (reflex) → K31.89
  • Gastrostenosis → K31.89
  • Gastrosuccorrhea (continuous) (intermittent) → K31.89
  • Hyperacidity (gastric) → K31.89
  • Hyperchlorhydria → K31.89
  • Hypoacidity, gastric → K31.89
  • Hypochlorhydria → K31.89
  • Megalogastria (acquired) → K31.89
  • Reichmann's disease or syndrome → K31.89
  • Rossbach's disease → K31.89
  • Subacidity, gastric → K31.89
  • Tachygastria → K31.89
  • Gastropathy → K31.9
  • Disease, diseasedBouchard's (myopathic dilatation of the stomach) → K31.0
  • Potain'ssyndrome (gastrectasis with dyspepsia) → K31.0
  • SyndromePotain's → K31.0
  • Constrictionpylorus (adult hypertrophic) → K31.1
  • Hypertrophy, hypertrophicpylorus (adult) (muscle) (sphincter) → K31.1
  • Obstruction, obstructed, obstructivegastric outlet → K31.1
  • Occlusion, occludedpylorus, adult → K31.1
  • Stenosis, stenotic (cicatricial)pylorus (hypertrophic) (acquired) → K31.1
  • Stricturepylorus (hypertrophic) → K31.1
  • Deformitycascade, stomach → K31.2
  • Stenosis, stenotic (cicatricial)stomach, hourglass → K31.2
  • Stricturehourglass, of stomach → K31.2
  • Spasm(s), spastic, spasticitypylorus NEC → K31.3

135 more, longer entries are not listed; the search box finds them by word.

NCHS Alphabetic Index. Index first, then the Tabular List.

Hierarchy