ICD-10 C33
Billable / Specific HCC v28: 9 CCMalignant neoplasm of trachea
About ICD-10-CM C33
ICD-10-CM code C33 represents Malignant neoplasm of trachea. This is a billable/specific code in the Neoplasms chapter (block C33). The 2026 edition of ICD-10-CM C33 became effective on October 1, 2025.
Coding Tips for C33
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
C33 is a CMS-HCC v28 risk-adjustment code (category 9). 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.
C33 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.
Use Additional Code
When coding C33, also report these additional codes when applicable.
- code to identify:
- exposure to environmental tobacco smoke (Z77.22)
- exposure to tobacco smoke in the perinatal period (P96.81)
- history of tobacco dependence (Z87.891)
- occupational exposure to environmental tobacco smoke (Z57.31)
- tobacco dependence (F17.-)
- tobacco use (Z72.0)
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 trachea. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for C33
Local Coverage Determinations (LCDs) from CMS MACs that list C33 as a covered diagnosis.
Showing top 10 of 1,526 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing C33.
2 Cigna
5 Medicare
CPT Codes Commonly Billed with C33
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 81540 CMS LCD: Billing and Coding: MolDX: bioTheranostics Cancer TYPE ID� Update CMS LCD
- 94726 CMS LCD: Billing and Coding: Respiratory Therapy (Respiratory Care) CMS LCD
- 94004 CMS LCD: Billing and Coding: Respiratory Therapy (Respiratory Care) CMS LCD
- 94621 CMS LCD: Billing and Coding: Respiratory Therapy (Respiratory Care) CMS LCD
- 94011 CMS LCD: Billing and Coding: Respiratory Therapy (Respiratory Care) CMS LCD
- 94003 CMS LCD: Billing and Coding: Respiratory Therapy (Respiratory Care) CMS LCD
- 94668 CMS LCD: Billing and Coding: Respiratory Therapy (Respiratory Care) CMS LCD
- 94070 CMS LCD: Billing and Coding: Respiratory Therapy (Respiratory Care) CMS LCD
- 94664 CMS LCD: Billing and Coding: Respiratory Therapy (Respiratory Care) CMS LCD
- 94012 CMS LCD: Billing and Coding: Respiratory Therapy (Respiratory Care) CMS LCD
Convert C33 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 |
|---|---|---|
| C33 | 1620 | 00000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To C33
Other codes in section C30-C39 (Malignant neoplasms of respiratory and intrathoracic organs).
ICD-10 C33, Billing FAQ
Is ICD-10 code C33 billable? +
Yes, C33 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
Does C33 affect Medicare Advantage HCC risk adjustment? +
Yes. C33 maps to CMS-HCC v28 category 9. Capture this diagnosis annually for accurate Medicare Advantage risk score.
Is C33 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 C33? +
Procedures frequently paired with C33 include: 81540, 94726, 94004, 94621, 94011.
What ICD-9 codes does C33 map to? +
Per CMS GEMs, C33 maps to ICD-9 codes: 1620. 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 May 31, 2026.
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