ICD-10 C34.12
Billable / Specific HCC v28: 9 CCMalignant neoplasm of upper lobe, left bronchus or lung
About ICD-10-CM C34.12
ICD-10-CM code C34.12 represents Malignant neoplasm of upper lobe, left bronchus or lung. This is a billable/specific code in the Neoplasms chapter (block C34). The 2026 edition of ICD-10-CM C34.12 became effective on October 1, 2025.
Coding Tips for C34.12
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
C34.12 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.
C34.12 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.
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 upper lobe, left bronchus or lung. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for C34.12
Local Coverage Determinations (LCDs) from CMS MACs that list C34.12 as a covered diagnosis.
Showing top 10 of 1,447 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing C34.12.
5 Medicare
CPT Codes Commonly Billed with C34.12
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 0288U CMS LCD: Billing and Coding: MolDX: Predictive Classifiers for Early Stage Non-Small Cell Lung Cancer CMS LCD
- 81540 CMS LCD: Billing and Coding: MolDX: bioTheranostics Cancer TYPE ID� Update CMS LCD
- 94618 CMS LCD: Billing and Coding: Pulmonary Stress Testing CMS LCD
- 94619 CMS LCD: Billing and Coding: Pulmonary Stress Testing CMS LCD
- 94617 CMS LCD: Billing and Coding: Pulmonary Stress Testing CMS LCD
- 81378 CMS LCD: Billing and Coding: Molecular Pathology Procedures CMS LCD
- 81372 CMS LCD: Billing and Coding: Molecular Pathology Procedures CMS LCD
- 81373 CMS LCD: Billing and Coding: Molecular Pathology Procedures CMS LCD
- 81371 CMS LCD: Billing and Coding: Molecular Pathology Procedures CMS LCD
- 81536 CMS LCD: Billing and Coding: Molecular Pathology Procedures CMS LCD
Convert C34.12 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 |
|---|---|---|
| C34.12 | 1623 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To C34.12
Other codes in section C30-C39 (Malignant neoplasms of respiratory and intrathoracic organs).
ICD-10 C34.12, Billing FAQ
Is ICD-10 code C34.12 billable? +
Yes, C34.12 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
Does C34.12 affect Medicare Advantage HCC risk adjustment? +
Yes. C34.12 maps to CMS-HCC v28 category 9. Capture this diagnosis annually for accurate Medicare Advantage risk score.
Is C34.12 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 C34.12? +
Procedures frequently paired with C34.12 include: 0288U, 81540, 94618, 94619, 94617.
What ICD-9 codes does C34.12 map to? +
Per CMS GEMs, C34.12 maps to ICD-9 codes: 1623. 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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