ICD-10 M05.79
Billable / Specific HCC v28: 40Rheumatoid arthritis with rheumatoid factor of multiple sites without organ or systems involvement
About ICD-10-CM M05.79
ICD-10-CM code M05.79 represents Rheumatoid arthritis with rheumatoid factor of multiple sites without organ or systems involvement. This is a billable/specific code in the Musculoskeletal and Connective Tissue chapter (block M05). The 2026 edition of ICD-10-CM M05.79 became effective on October 1, 2025.
Coding Tips for M05.79
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
M05.79 is a CMS-HCC v28 risk-adjustment code (category 40). 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.
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.
Medicare LCD Coverage for M05.79
Local Coverage Determinations (LCDs) from CMS MACs that list M05.79 as a covered diagnosis.
Showing top 10 of 470 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing M05.79.
1 Cigna
5 Medicare
CPT Codes Commonly Billed with M05.79
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 99205 New patient office visit — complex/high-risk: uncontrolled diabetes, heart failure, COPD exacerbation, cancer, MS, RA, CKD, CAD, recurrent depression, epilepsy, lupus, syncope, cognitive decline Primary Care
- 99215 Established patient — high complexity: HF exacerbation, COPD exacerbation, cancer management, MS, advanced CKD, uncontrolled diabetes, recurrent syncope, respiratory failure, liver cirrhosis Primary Care
- 81599 CMS LCD: Billing and Coding: MolDX: Molecular Biomarker Testing to Guide Targeted Therapy Selection in Rheumatoid Arthritis CMS LCD
- 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
Convert M05.79 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 |
|---|---|---|
| M05.79 | 7140 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To M05.79
Other codes in section M05-M14 (Inflammatory polyarthropathies).
ICD-10 M05.79, Billing FAQ
Is ICD-10 code M05.79 billable? +
Yes, M05.79 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
Does M05.79 affect Medicare Advantage HCC risk adjustment? +
Yes. M05.79 maps to CMS-HCC v28 category 40. Capture this diagnosis annually for accurate Medicare Advantage risk score.
What CPT codes are commonly billed with M05.79? +
Procedures frequently paired with M05.79 include: 99205, 99215, 81599, 27134, 27132.
What ICD-9 codes does M05.79 map to? +
Per CMS GEMs, M05.79 maps to ICD-9 codes: 7140. 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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