K31.6
Fistula of stomach and duodenum
K31.6 (also written K316) is a billable ICD-10-CM diagnosis code for fistula of stomach and duodenum. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 26 codes in category K31 (Other diseases of stomach and duodenum). The Alphabetic Index lists it under 8 entries. Its coding notes include a Code also instruction and 11 Excludes2 entries.
Code also
Two codes may be needed to describe the condition. This note gives no sequencing order.
- , if applicable, disruption of internal operation (surgical) wound (T81.32-)
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (9 notes)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Gastrointestinal tract and Genitourinary system clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026Hospital CC
Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 10 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.
Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix CIncludes
Further defines or gives examples of the content of the category.
- functional disorders of stomach
Inclusion terms
Conditions classified to this code.
- Gastrocolic fistula
- Gastrojejunocolic fistula
Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 8 entries