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ICD-10-CM K50.813: Crohn's disease of both small and large intestine with fistula

K50.813 is the billable ICD-10-CM code for crohn's disease of both small and large intestine with fistula, in category K50 (Crohn's disease [regional enteritis]) of the Noninfective enteritis and colitis section. As a principal diagnosis it groups to MS-DRG 385 Inflammatory Bowel Disease with MCC, MS-DRG 386 Inflammatory Bowel Disease with CC, MS-DRG 387 Inflammatory Bowel Disease without CC/MCC (MDC 06 MDC 06: Diseases and Disorders of the Digestive System). It maps to HCC 80 (Crohn's Disease (Regional Enteritis)) in CMS-HCC V28. As a secondary diagnosis it is a CC, excluded with 77 principal diagnoses. 30 LCD billing and coding articles list it as covered.

Compiled from CMS files by the QuickIntell RCM Editorial Team · Data effective · Method: reference methodology · Report a data correction

Data currency: ICD-10-CM code descriptions: FY2027 (effective October 1, 2026); IPPS Table 5 (MS-DRG weights): v44 FY2027 (final rule + CN3) (effective October 1, 2026); ICD-10-CM to HCC mapping: PY2027 initial ICD-10-CM mappings (dates of service 2026) (payment year 2027); Medicare Coverage Database billing and coding articles: MCD release October 8, 2026 (effective October 4, 2026). Next CMS release: FY2028 code files, effective October 1, 2027 for the ICD-10-CM code descriptions; FY2028 final rule (August 2027), effective October 1, 2027; an April 1 interim grouper update when CMS issues one for the IPPS Table 5 (MS-DRG weights); PY2028 advance notice (February 2027) and the PY2027 midyear final mapping (spring 2027) for the ICD-10-CM to HCC mapping; weekly, every Thursday for the Medicare Coverage Database billing and coding articles.

Code
K50.813
billable FY2027 ICD-10-CM code
Category
K50 Crohn's disease [regional enteritis]
Chapter
11: Diseases of the digestive system (K00-K95)
CC/MCC (MS-DRG v44)
CC
CMS-HCC V28
HCC 80
POA reporting
Required

Tabular list notes for K50.813

The tabular list has no notes on K50.813 itself; the notes below apply from its parent headings.

Inherited from K50 (Crohn's disease [regional enteritis])

Includes
  • granulomatous enteritis
Excludes1 (never coded together)
  • ulcerative colitis (K51.-)
Use additional code
  • code to identify any associated fistulas, if applicable:
  • anal fistula (K60.3-)
  • anorectal fistula (K60.5-)
  • rectal fistula (K60.4-)
  • code to identify manifestations, such as:
  • pyoderma gangrenosum (L88)

MS-DRG grouping when K50.813 is the principal diagnosis

MS-DRG v44 groups for K50.813 as principal diagnosis
MDCMS-DRGs
06 MDC 06: Diseases and Disorders of the Digestive System385386387

The final group also depends on procedures, secondary diagnoses and discharge status; the MS-DRG lookup for K50.813 shows the full grouping logic.

CC/MCC status and inpatient edits

As a secondary diagnosis, K50.813 is a CC under MS-DRG v44, unless the principal diagnosis is one of the 77 codes in its exclusion list. Check K50.813 against a principal diagnosis.

  • Present on admission: a POA indicator is required on inpatient claims.

CMS-HCC V28 risk adjustment

In the PY2027 mapping, K50.813 maps to HCC 80 (Crohn's Disease (Regional Enteritis)). The HCC lookup shows the RAF weight and the hierarchy.

LCD billing and coding articles that list K50.813

30 current Medicare billing and coding articles list K50.813 among the diagnoses that support medical necessity for the services they cover.

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Frequently asked questions

What does ICD-10-CM K50.813 mean?

K50.813 means crohn's disease of both small and large intestine with fistula. It is one of 25 billable codes under K50, crohn's disease [regional enteritis].

Which MS-DRG does K50.813 group to?

As the principal diagnosis, K50.813 groups to MS-DRG 385 Inflammatory Bowel Disease with MCC, MS-DRG 386 Inflammatory Bowel Disease with CC, MS-DRG 387 Inflammatory Bowel Disease without CC/MCC (MDC 06 MDC 06: Diseases and Disorders of the Digestive System) under MS-DRG v44, before procedures and secondary diagnoses are applied.

Does K50.813 map to an HCC?

Yes: HCC 80, Crohn's Disease (Regional Enteritis), in the PY2027 CMS-HCC V28 mapping.

Is K50.813 a CC or MCC?

K50.813 is a CC under MS-DRG v44; 77 principal diagnoses exclude it.

Sources

Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-10. Verify against the primary file before billing or contracting decisions. The reference methodology explains how each figure is computed from these files.

Disclaimer

The descriptor and notes are reproduced from the FY2027 ICD-10-CM files; MS-DRG, CC/MCC and HCC facts come from the CMS FY2027 and PY2027 tables. Code from the medical record and the ICD-10-CM Official Guidelines. Not legal, clinical or billing advice.

Found a figure that does not match the CMS file? Report a data correction with the CMS file and the value you expected; the request reaches the editorial team through the contact form.