C34.01 ICD-10-CM Code: Malignant neoplasm of right main bronchus
C34.01 maps to CMS-HCC V28 20. 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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FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of respiratory and intrathoracic organs (C30-C39)
C34.01
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceMalignant neoplasm of right main bronchus
This code describes cancer that starts in the main airway (bronchus) on the right side of the lungs. It is a malignant tumor that originates in this specific location rather than spreading from elsewhere.
Buddy Insight
Right main bronchus cancer specifies laterality for central lung malignancy, which is important for surgical planning and radiation targeting.
CMS-HCC V28
MappedHCC 20
Code-level coefficient reference
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 009
Code-level coefficient reference
ESRD/PACE
MappedHCC 9
Code-level coefficient reference
RXHCC
MappedHCC 20
Code-level coefficient reference
Code Book Path
Inclusion Terms
Official- Malignant neoplasm of carinaInherited from C34.0
- Malignant neoplasm of hilus (of lung)Inherited from C34.0
Excludes 2
OfficialNo Excludes 2 notes are included in this display for C34.01. Check the code and parent instructions in the Code Book.
Related Codes
Includes
Official- malignant neoplasm of middle earInherited from C30-C39
Excludes 1
Official- mesothelioma (C45.-)Inherited from C30-C39, C34
- Kaposi's sarcoma of lung (C46.5-)Inherited from C30-C39, C34
- malignant carcinoid tumor of the bronchus and lung (C7A.090)Inherited from C30-C39, C34
Code First
OfficialNo Code First sequencing instructions are included in this display for C34.01. Check the code and parent instructions in the Code Book.
Use Additional
Official- code to identify:Inherited from C34
- exposure to environmental tobacco smoke (Z77.22)Inherited from C34
- exposure to tobacco smoke in the perinatal period (P96.81)Inherited from C34
- history of tobacco dependence (Z87.891)Inherited from C34
- occupational exposure to environmental tobacco smoke (Z57.31)Inherited from C34
- tobacco dependence (F17.-)Inherited from C34
- tobacco use (Z72.0)Inherited from C34
Code Also
OfficialNo Code Also instructions are included in this display for C34.01. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
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 C34.01 an HCC code?
Yes. C34.01 (Malignant neoplasm of right main bronchus) maps to HCC 20, Lung and Other Severe Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 1.136. 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: C34.01 is billable and maps to V28 HCC 20, Lung and Other Severe Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- C34.01
- Description
- Malignant neoplasm of right main bronchus
- HCC (V28)
- HCC 20 — Lung and Other Severe Cancers
- RAF reference coefficient
- 1.136
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
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 C34.01 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for C34.01
For C34.01, 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
C34.01 is the ICD-10-CM diagnosis code for malignant neoplasm of right main bronchus. This code describes cancer that starts in the main airway (bronchus) on the right side of the lungs. It is a malignant tumor that originates in this specific location rather than spreading from elsewhere. C34.01 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of respiratory and intrathoracic organs (c30-c39).
Under the CMS-HCC V28 risk adjustment model, C34.01 maps to Lung and Other Severe Cancers (HCC 20) with a source-labeled community, non-dual, aged reference coefficient of 1.136. No V24 mapping is shown for C34.01; 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.
Verify laterality is documented as right-sided in the medical record before assigning this code; do not assume based on imaging alone. For C34.01, 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 C34.01 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify laterality is documented as right-sided in the medical record before assigning this code; do not assume based on imaging alone
- •This is a more specific code than C34.9 (unspecified lung cancer), so use it when the main bronchus location is clearly documented by the provider
Clinical Significance
Right main bronchus cancer specifies laterality for central lung malignancy, which is important for surgical planning and radiation targeting. The right main bronchus is shorter and wider than the left, making it more susceptible to foreign body aspiration and potentially earlier symptom presentation. Right-sided tumors may involve the right upper lobe takeoff.
Documentation Requirements
- ✓Pathology with histological type and molecular markers (EGFR, ALK, PD-L1 for non-small cell)
- ✓Bronchoscopy or CT confirming right main bronchus as the tumor site
- ✓Documentation of laterality explicitly stated as right-sided
- ✓TNM staging with assessment of mediastinal node involvement
- ✓Surgical candidacy assessment including pulmonary function
Commonly Confused Codes
- •C34.02: Left main bronchus: Ensure laterality matches documentation
- •C34.11: Right upper lobe: Main bronchus is proximal to lobar bronchi; distinguish the exact location
- •C34.00: Unspecified main bronchus: Use C34.01 when right side is documented
- •C34.91: Right lung, unspecified part: C34.01 is more specific when main bronchus origin is confirmed