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C26.0 ICD-10-CM Code: Malignant neoplasm of intestinal tract, part unspecified

C26.0 maps to CMS-HCC V28 22. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC coding software

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Code lookupC26.0

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of digestive organs (C15-C26)

C26.0

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

Malignant neoplasm of intestinal tract, part unspecified

Cancer of the intestinal tract where the specific part of the intestines affected is not clearly identified.

Buddy the Bee presenting code insight

Buddy Insight

This code represents malignant neoplasm of the intestinal tract when the specific segment (small intestine, colon, rectum) cannot be determined.

OverviewRisk ModelsCode BookDocumentationAuditNotesEdition comparison

CMS-HCC V28

HCC 22

Coefficient HCC 22: 0.363 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

HCC 011

Code-level coefficient reference

ESRD/PACE

HCC 11

Code-level coefficient reference

RXHCC

N/A

—

Not mapped

Code Book Path

Official
C26Malignant neoplasm of other and ill-defined digestive organsC26.0Malignant neoplasm of intestinal tract, part unspecified

Inclusion Terms

Official
  • Malignant neoplasm of intestine NOS

Excludes 2

Official
  • gastrointestinal stromal tumors (C49.A-)Inherited from C15-C26

Related Codes

Official
C26.1Malignant neoplasm of spleenC26.9Malignant neoplasm of ill-defined sites within the digestive system

Includes

Official

No Includes notes are included in this display for C26.0. Check the code and parent instructions in the Code Book.

Excludes 1

Official
  • Kaposi's sarcoma of gastrointestinal sites (C46.4)Inherited from C15-C26, C26
  • malignant neoplasm of peritoneum and retroperitoneum (C48.-)Inherited from C15-C26, C26

Code First

Official

No Code First sequencing instructions are included in this display for C26.0. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for C26.0. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for C26.0. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance
Pathology confirmation of intestinal malignancy
Documentation that specific intestinal segment cannot be identified
Evidence of provider query for anatomical specificity
Imaging and endoscopy reports reviewed for location detail

MEAT Support

HCC Buddy guidance
Pathology confirmation of intestinal malignancy
Documentation that specific intestinal segment cannot be identified
Evidence of provider query for anatomical specificity
Imaging and endoscopy reports reviewed for location detail

Audit Caution

HCC Buddy guidance
Using this code when colonoscopy or imaging clearly identifies the segment — always code to highest specificity
Not querying the provider when surgical or endoscopy reports are available with location detail
Confusing this with C26.9 (ill-defined digestive system) which is even less specific
Missing the opportunity to capture a more specific code that would still map to the same HCC

Common Mistakes

HCC Buddy guidance
C18.9 — Malignant neoplasm of colon, unspecified: If the tumor is known to be colonic, use C18.9 instead
C17.9 — Malignant neoplasm of small intestine, unspecified: Use when small intestine origin is confirmed
C20 — Malignant neoplasm of rectum: Rectal cancers have distinct treatment protocols and should not default to C26.0
C26.9 — Ill-defined digestive system: C26.0 is specific to intestinal tract; C26.9 covers broader digestive system

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 C26.0 an HCC code?

Yes. C26.0 (Malignant neoplasm of intestinal tract, part unspecified) maps to HCC 22, Bladder, Colorectal, and Other Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.363. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: C26.0 is billable and maps to V28 HCC 22, Bladder, Colorectal, and Other Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
C26.0
Description
Malignant neoplasm of intestinal tract, part unspecified
HCC (V28)
HCC 22 — Bladder, Colorectal, and Other Cancers
RAF reference coefficient
0.363
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 22, Bladder, Colorectal, and Other Cancers
0.363
ESRDHCC 11, Colorectal/Bladder/and Other Cancers
Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. 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 context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work C26.0 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for C26.0

For C26.0, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

  • 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

Coder workflow notes

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What This Code Means

C26.0 is the ICD-10-CM diagnosis code for malignant neoplasm of intestinal tract, part unspecified. Cancer of the intestinal tract where the specific part of the intestines affected is not clearly identified. C26.0 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of digestive organs (c15-c26).

Under the CMS-HCC V28 risk adjustment model, C26.0 maps to Bladder, Colorectal, and Other Cancers (HCC 22) with a source-labeled community, non-dual, aged reference coefficient of 0.363. No V24 mapping is shown for C26.0; use the applicable model and payment year when reviewing the V28 mapping. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

This code indicates insufficient specificity; attempt to determine if cancer is in small intestine, colon, or rectum. For C26.0, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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, source-labeled coefficient references, and MEAT documentation criteria for C26.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •This code indicates insufficient specificity; attempt to determine if cancer is in small intestine, colon, or rectum
  • •Review pathology reports and imaging studies to identify the precise intestinal location

Clinical Significance

This code represents malignant neoplasm of the intestinal tract when the specific segment (small intestine, colon, rectum) cannot be determined. This is a clinically significant gap in documentation because treatment protocols and prognosis differ dramatically between intestinal segments. It carries a lower HCC weight than pancreatic or lung cancers but still impacts risk adjustment.

Documentation Requirements

  • ✓Pathology confirmation of intestinal malignancy
  • ✓Documentation that specific intestinal segment cannot be identified
  • ✓Evidence of provider query for anatomical specificity
  • ✓Imaging and endoscopy reports reviewed for location detail
  • ✓Treatment status and disease stage

Commonly Confused Codes

  • •C18.9: Malignant neoplasm of colon, unspecified: If the tumor is known to be colonic, use C18.9 instead
  • •C17.9: Malignant neoplasm of small intestine, unspecified: Use when small intestine origin is confirmed
  • •C20: Malignant neoplasm of rectum: Rectal cancers have distinct treatment protocols and should not default to C26.0
  • •C26.9: Ill-defined digestive system: C26.0 is specific to intestinal tract; C26.9 covers broader digestive system

Child Codes

C26.0Malignant neoplasm of intestinal tract, part unspecified
HCC 22
C26.1Malignant neoplasm of spleen
HCC 22
C26.9Malignant neoplasm of ill-defined sites within the digestive system
HCC 22

Code Hierarchy

└C26Malignant neoplasm of other and ill-defined digestive organs└C26.0Malignant neoplasm of intestinal tract, part unspecified
└C26.0Malignant neoplasm of intestinal tract, part unspecified

Also searched as

  • C26 0
  • C260

For C26.0, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

C26.0 maps to CMS-HCC V28 category 22, Bladder, Colorectal, and Other Cancers. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for C26.0. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

More on C26.0

Referenced in blog posts

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