ICD-10 C19
Billable / Specific HCC v28: 11 CCMalignant neoplasm of rectosigmoid junction
About ICD-10-CM C19
ICD-10-CM code C19 represents Malignant neoplasm of rectosigmoid junction. This is a billable/specific code in the Neoplasms chapter (block C19). The 2026 edition of ICD-10-CM C19 became effective on October 1, 2025.
Coding Tips for C19
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
C19 is a CMS-HCC v28 risk-adjustment code (category 11). To count for the patient Risk Adjustment Factor (RAF), document the diagnosis with MEAT language each calendar year: Monitored, Evaluated, Assessed, Treated. A diagnosis on the problem list alone does not satisfy CMS RADV audit standards. Include the diagnosis in the assessment with current status and current treatment plan.
C19 is designated CC for MS-DRG grouping. On inpatient claims, this code can shift the DRG to the with-CC variant when documented as a present-on-admission secondary diagnosis. Hospital CDI programs flag CC opportunities during chart review. Failure to capture this code may leave 30 to 80 percent of the inpatient stay revenue unrealized.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under C19. Per CMS ICD-10-CM Tabular 2026.
- Malignant neoplasm of colon with rectum
- Malignant neoplasm of rectosigmoid (colon)
Type 1 Excludes
Pure excludes, these codes can never be coded together with C19. The conditions are mutually exclusive (e.g., congenital vs acquired forms).
- malignant carcinoid tumors of the colon (C7A.02-)
Medicare Advantage HCC Impact
Capture this diagnosis annually for accurate risk adjustment. Missed HCC captures are the #1 revenue leak in Medicare Advantage risk programs.
Inpatient DRG Impact, CC
codes Malignant neoplasm of rectosigmoid junction. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for C19
Local Coverage Determinations (LCDs) from CMS MACs that list C19 as a covered diagnosis.
Showing top 10 of 1,759 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing C19.
1 Aetna
3 Cigna
5 Medicare
CPT Codes Commonly Billed with C19
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 44408 CMS LCD: Billing and Coding: Diagnostic Colonoscopy CMS LCD
- 45379 CMS LCD: Billing and Coding: Diagnostic Colonoscopy CMS LCD
- 44406 CMS LCD: Billing and Coding: Diagnostic Colonoscopy CMS LCD
- 45390 CMS LCD: Billing and Coding: Diagnostic Colonoscopy CMS LCD
- 45392 CMS LCD: Billing and Coding: Diagnostic Colonoscopy CMS LCD
- 44394 CMS LCD: Billing and Coding: Diagnostic Colonoscopy CMS LCD
- 44402 CMS LCD: Billing and Coding: Diagnostic Colonoscopy CMS LCD
- 44390 CMS LCD: Billing and Coding: Diagnostic Colonoscopy CMS LCD
- 44405 CMS LCD: Billing and Coding: Diagnostic Colonoscopy CMS LCD
- 44388 CMS LCD: Billing and Coding: Diagnostic Colonoscopy CMS LCD
Convert C19 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| C19 | 1540 | 00000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To C19
Other codes in section C15-C26 (Malignant neoplasms of digestive organs).
ICD-10 C19, Billing FAQ
Is ICD-10 code C19 billable? +
Yes, C19 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to C19? +
ICD-10 C19 includes: Malignant neoplasm of colon with rectum; Malignant neoplasm of rectosigmoid (colon).
What codes are Type 1 Excludes for C19? +
Type 1 Excludes (never code together with C19): malignant carcinoid tumors of the colon (C7A.02-)
Does C19 affect Medicare Advantage HCC risk adjustment? +
Yes. C19 maps to CMS-HCC v28 category 11. Capture this diagnosis annually for accurate Medicare Advantage risk score.
Is C19 a CC or MCC for inpatient DRG? +
Yes, this code is designated as CC. Documenting as a secondary diagnosis on inpatient claims can shift the DRG to a higher-weighted category.
What CPT codes are commonly billed with C19? +
Procedures frequently paired with C19 include: 44408, 45379, 44406, 45390, 45392.
What ICD-9 codes does C19 map to? +
Per CMS GEMs, C19 maps to ICD-9 codes: 1540. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on June 1, 2026.
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