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

K50.813 maps to CMS-HCC V28 80 (RAF 0.550). Documentation must support MEAT. MEAT criteria · RAF calculator · HCC Buddy coding tools

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FY 2026 Apr update / Diseases of the digestive system (K00-K95) / Noninfective enteritis and colitis (K50-K52)

K50.813

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Crohn's disease of both small and large intestine with fistula

Crohn's disease affecting both the small and large intestines with an abnormal tunnel-like connection (fistula) between intestinal structures or other organs.

Buddy the Bee presenting code insight

Buddy Insight

Crohn's disease of both small and large intestine with fistula indicates penetrating ileocolonic disease, which is the most common disease phenotype to develop fistulas.

CMS-HCC V28

HCC 80

RAF 0.550

CMS-HCC V24

HCC 35

RAF 0.308

ACA/HHS

HCC 48

Varies by metal level

ESRD/PACE

HCC 35

RAF 0.048

RXHCC

HCC 67

RAF 0.494

Code Book Path

Official
K50.8Crohn's disease of both small and large intestine
K50.81Crohn's disease of both small and large intestine with complications
K50.813Crohn's disease of both small and large intestine with fistula

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for K50.813 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for K50.813 in this effective period.

Related Child Codes

Official
K50.811Crohn's disease of both small and large intestine with rectal bleeding
K50.812Crohn's disease of both small and large intestine with intestinal obstruction
K50.814Crohn's disease of both small and large intestine with abscess
K50.818Crohn's disease of both small and large intestine with other complication
K50.819Crohn's disease of both small and large intestine with unspecified complications

Includes

Official

ICD-10-CM does not list Includes notes for K50.813 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for K50.813 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for K50.813 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for K50.813 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for K50.813 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Provider documentation of Crohn's disease involving both small and large intestine with fistula
Confirmation of both anatomic sites being affected
Type and location of fistula documented
Diagnostic method confirming fistula (MRI pelvis, CT, fistulogram, examination under anesthesia)

MEAT Support

HCC Buddy guidance
Provider documentation of Crohn's disease involving both small and large intestine with fistula
Confirmation of both anatomic sites being affected
Type and location of fistula documented
Diagnostic method confirming fistula (MRI pelvis, CT, fistulogram, examination under anesthesia)

Audit Caution

HCC Buddy guidance
Not specifying ileocolonic involvement when both sites are documented
Coding the fistula separately instead of using the combination code
Confusing fistula with abscess — though they often coexist, they are different complications
Using a site-unspecified code when the ileocolonic location is clearly documented

Common Mistakes

HCC Buddy guidance
K50.80 — Crohn's disease of both sites without complications: no fistula present
K50.013 — Crohn's disease of small intestine with fistula: small intestine only
K50.113 — Crohn's disease of large intestine with fistula: large intestine only
K50.814 — Crohn's disease of both sites with abscess: abscess vs. fistula

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is K50.813 an HCC code?

Yes. K50.813 (Crohn's disease of both small and large intestine with fistula) maps to Crohn's Disease (Regional Enteritis) under the CMS-HCC V28 risk adjustment model (and Inflammatory Bowel Disease under V24), with a community non-dual aged RAF of 0.550. It is billable for payment year 2026.

Coder answer: K50.813 is billable and maps to V28 HCC 80, Crohn's Disease (Regional Enteritis). Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
K50.813
Description
Crohn's disease of both small and large intestine with fistula
HCC (V28)
HCC 80 — Crohn's Disease (Regional Enteritis)
RAF
0.550
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 80, Crohn's Disease (Regional Enteritis)
0.550
V24HCC 35, Inflammatory Bowel Disease
0.308
ESRDHCC 35, Inflammatory Bowel Disease
0.048
RxHCCHCC 67, Inflammatory Bowel Disease
0.494

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work K50.813 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for K50.813

For K50.813 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

  • MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
  • EEvaluate: test results, medication response, or physical findings reviewed by the provider
  • AAssess: explicit mention in the assessment or plan with acknowledgment of status
  • TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed K50.813 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

K50.813 is the ICD-10-CM diagnosis code for crohn's disease of both small and large intestine with fistula. Crohn's disease affecting both the small and large intestines with an abnormal tunnel-like connection (fistula) between intestinal structures or other organs. K50.813 sits in the ICD-10-CM chapter for diseases of the digestive system (k00-k95), within the section covering noninfective enteritis and colitis (k50-k52).

Under the CMS-HCC V28 risk adjustment model, K50.813 maps to Crohn's Disease (Regional Enteritis) (HCC 80) with a community, non-dual, aged base RAF weight of 0.550. Under the older CMS-HCC V24 model, K50.813 maps to Inflammatory Bowel Disease (HCC 35) with a community, non-dual, aged base RAF weight of 0.308. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

Document the specific type and location of fistula when available for complete clinical picture. Because K50.813 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for K50.813 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Document the specific type and location of fistula when available for complete clinical picture
  • •Fistulas in ileocolonic disease are common and may require surgical intervention

Clinical Significance

Crohn's disease of both small and large intestine with fistula indicates penetrating ileocolonic disease, which is the most common disease phenotype to develop fistulas. Fistulas in ileocolonic Crohn's may be enteroenteric, enterocutaneous, or involve the bladder, vagina, or skin. This complication often requires combination therapy with biologics and surgical intervention.

Documentation Requirements

  • ✓Provider documentation of Crohn's disease involving both small and large intestine with fistula
  • ✓Confirmation of both anatomic sites being affected
  • ✓Type and location of fistula documented
  • ✓Diagnostic method confirming fistula (MRI pelvis, CT, fistulogram, examination under anesthesia)
  • ✓Treatment plan (biologics, seton placement, surgical intervention)

Commonly Confused Codes

  • •K50.80: Crohn's disease of both sites without complications: no fistula present
  • •K50.013: Crohn's disease of small intestine with fistula: small intestine only
  • •K50.113: Crohn's disease of large intestine with fistula: large intestine only
  • •K50.814: Crohn's disease of both sites with abscess: abscess vs. fistula
  • •K63.2: Fistula of intestine: not attributed to Crohn's disease

Child Codes

K50.811Crohn's disease of both small and large intestine with rectal bleeding
HCC 80
K50.812Crohn's disease of both small and large intestine with intestinal obstruction
HCC 78
K50.813Crohn's disease of both small and large intestine with fistula
HCC 80
K50.814Crohn's disease of both small and large intestine with abscess
HCC 80
K50.818Crohn's disease of both small and large intestine with other complication
HCC 80
K50.819Crohn's disease of both small and large intestine with unspecified complications
HCC 80

Code Hierarchy

└K50Crohn's disease [regional enteritis]└K50.8Crohn's disease of both small and large intestine└K50.81Crohn's disease of both small and large intestine with complications└K50.813Crohn's disease of both small and large intestine with fistula
└K50.813Crohn's disease of both small and large intestine with fistula

Because K50.813 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

K50.813 maps to CMS-HCC V28 category 80, Crohn's Disease (Regional Enteritis). See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. Because K50.813 carries a payment HCC, you can see what it adds to a RAF score and check the documentation the chart needs before it is submitted.

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Open K50.813 in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 7 days to try everything, no card required.

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