ICD-10-CM 2027
ICD-10 code for duodenum fistula
From the official ICD-10-CM alphabetic index entry “Fistula (cutaneous) › duodenum”. Page updated September 29, 2026.
About coding duodenum fistula
The ICD-10-CM code for duodenum fistula is K31.6 (Fistula of stomach and duodenum).
Within K31 (other diseases of stomach and duodenum), K31.6 is specifically for fistula of stomach and duodenum. Related codes cover acute dilatation of stomach (K31.0), adult hypertrophic pyloric stenosis (K31.1), Hourglass stricture and stenosis of stomach (K31.2), Pylorospasm, not elsewhere classified (K31.3), gastric diverticulum (K31.4), obstruction of duodenum (K31.5), polyp of stomach and duodenum (K31.7), other specified diseases of stomach and duodenum (K31.8) and 3 more.
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.
In MS-DRG v44.0, it is part of the grouping logic for DRG 391 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders with MCC, relative weight 1.2392) and DRG 392 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders without MCC, relative weight 0.7645), in MDC 06 (Diseases and Disorders of the Digestive System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Common questions about duodenum fistula ICD-10 codes
What is the ICD-10 code for duodenum fistula?
- K31.6 — Fistula of stomach and duodenum.
Is K31.6 billable?
- Yes. K31.6 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can K31.6 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict K31.6 as a principal diagnosis.
Is K31.6 a CC or MCC?
- K31.6 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.