ICD-10 C49.21
Billable / Specific HCC v28: 10 CCMalignant neoplasm of connective and soft tissue of right lower limb, including hip
About ICD-10-CM C49.21
ICD-10-CM code C49.21 represents Malignant neoplasm of connective and soft tissue of right lower limb, including hip. This is a billable/specific code in the Neoplasms chapter (block C49). The 2026 edition of ICD-10-CM C49.21 became effective on October 1, 2025.
Coding Tips for C49.21
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
C49.21 is a CMS-HCC v28 risk-adjustment code (category 10). 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.
C49.21 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 connective and soft tissue of right lower limb, including hip. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for C49.21
Local Coverage Determinations (LCDs) from CMS MACs that list C49.21 as a covered diagnosis.
Showing top 10 of 873 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing C49.21.
5 Medicare
CPT Codes Commonly Billed with C49.21
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 27134 CMS LCD: Billing and Coding: Major Joint Replacement (Hip and Knee) CMS LCD
- 27132 CMS LCD: Billing and Coding: Major Joint Replacement (Hip and Knee) CMS LCD
- 27138 CMS LCD: Billing and Coding: Major Joint Replacement (Hip and Knee) CMS LCD
- 27137 CMS LCD: Billing and Coding: Major Joint Replacement (Hip and Knee) CMS LCD
- 27487 CMS LCD: Billing and Coding: Major Joint Replacement (Hip and Knee) CMS LCD
- 27486 CMS LCD: Billing and Coding: Major Joint Replacement (Hip and Knee) CMS LCD
- 27445 CMS LCD: Billing and Coding: Total Joint Arthroplasty CMS LCD
- 0054T CMS LCD: Billing and Coding: Total Joint Arthroplasty CMS LCD
- 20985 CMS LCD: Billing and Coding: Total Joint Arthroplasty CMS LCD
- S2900 CMS LCD: Billing and Coding: Total Joint Arthroplasty CMS LCD
Convert C49.21 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 |
|---|---|---|
| C49.21 | 1713 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To C49.21
Other codes in section C45-C49 (Malignant neoplasms of mesothelial and soft tissue).
ICD-10 C49.21, Billing FAQ
Is ICD-10 code C49.21 billable? +
Yes, C49.21 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
Does C49.21 affect Medicare Advantage HCC risk adjustment? +
Yes. C49.21 maps to CMS-HCC v28 category 10. Capture this diagnosis annually for accurate Medicare Advantage risk score.
Is C49.21 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 C49.21? +
Procedures frequently paired with C49.21 include: 27134, 27132, 27138, 27137, 27487.
What ICD-9 codes does C49.21 map to? +
Per CMS GEMs, C49.21 maps to ICD-9 codes: 1713. 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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