V24 to V28

CMS-HCC V28: Phased Implementation, RAF Impacts, and Major Coding Shifts 

The CMS-HCC Version 28 Risk Adjustment Model is one of the most significant updates in Medicare Advantage (MA) payment methodology in recent years. This phased rollout brings with it sweeping changes in diagnosis mapping, HCC structure, and RAF calculations that will impact provider documentation, MAO revenue, and CMS payments. 

Here’s what MA plans, coders, and providers need to know. 

🔄 Phased Implementation Timeline 

  • PY 2024: 67% RAF scores from V24, 33% from V28 

  • PY 2025: 33% RAF scores from V24, 67% from V28 

  • PY 2026: 100% RAF scores based on V28 

MAOs need dual-model readiness now to manage this transition. Health plans must revise analytics models, retrain staff, and prepare providers for documentation expectations aligned to the V28 logic. Since scoring methodologies will blend in 2024 and 2025, dual-mapped submissions and comparative impact assessments are essential. 

📈 Key Model Updates in V28 

  • Uses 2018 diagnosis and 2019 expenditure data, creating more current alignment 

  • Enhanced model reflects clinically stable and predictive diagnoses, improving precision 

  • Stronger mapping with modern ICD-10 code structure results in greater granularity and fewer misclassifications 

These upgrades ensure risk scoring keeps pace with evolving coding standards and clinical guidelines. 

🔢 Diagnosis & HCC Category Changes 

  1. Diagnoses Mapped

    • The number of diagnoses mapped to HCCs has decreased from 9,797 in V24 to 7,770 in V28. This reduction ensures only clinically relevant and cost-predictive diagnoses are retained.

  2. Payment HCCs Expanded

    • V24 had 86 payment HCC categories.

    • V28 expands this to 115, allowing for more nuanced representation of patient conditions and risk.

  3. New HCCs Added in V28

    • 209 new ICD-10-CM codes have been mapped to HCCs in V28.

    • Many of these are focused on capturing conditions with stronger predictive value, including behavioral health and rare diseases.

  4. Significant Removals

    • V28 removes 2,236 ICD-10-CM codes that were previously mapped to HCCs in V24.

    • These codes were excluded for having weak associations with future healthcare costs or poor documentation support

Fewer mapped diagnoses in V28 reflect CMS's goal of eliminating codes with poor predictive value and ensuring every code that contributes to the RAF score has strong clinical justification. 

➕ Notable New HCC Additions 

  • HCC 298 – Retinal Vein Occlusion 

  • HCC 279 – Severe Persistent Asthma 

  • HCC 153 – Eating Disorders (Anorexia, Bulimia) 

  • HCC 22 – Benign Carcinoid Tumor 

  • HCC 17 – Malignant Pleural Effusion 

These additions better capture high-acuity patients whose conditions were previously unrecognized under the payment model. 

🚫 Removed HCCs (Examples) 

  • HCC 21 – Protein Calorie Malnutrition 

  • HCC 23 – Parathyroid & Metabolic Diseases 

  • HCC 88 – Angina Pectoris 

  • HCC 59 – Mild Major Depression, Substance Abuse 

  • HCC 134/135 – Dialysis Status, Acute Renal Failure 

Removing these codes improves model integrity but may reduce scores for members with low-cost, non-predictive conditions. Providers must stay informed to avoid coding obsolete diagnoses. 

♻ Renumbering and Group Expansion 

  • Neoplasm group expanded from 5 to 7 HCCs, creating better differentiation across tumor types 

  • Other categories, such as vascular and endocrine conditions, were similarly expanded and refined 

🔀 Dual HCC Mapping (Examples) 

  • Diabetes with macular edema → HCC 37 + HCC 298 

  • Heart-lung transplant complications → HCC 221 + HCC 276 

Dual-mapped codes reflect the complexity of some conditions that span multiple organ systems or complications. They provide richer context for RAF calculation and stratification. 

📆 Constraining and RAF Score Impacts 

  • V28 constrains RAF values by grouping diagnoses with similar cost profiles 

  • Equal coefficient values now apply to some conditions regardless of severity or complications 

  • For example, diabetes with and without complications may now carry the same RAF 

  • CMS projects an average RAF decrease of 3.12% for MA plans in 2024 

  • Estimated $11B in Medicare Trust Fund savings expected from V28 changes in 2024 alone 

Plans must recalibrate revenue expectations and prepare coding workflows that prioritize fully supported, risk-adjustable diagnoses. 

📅 Key Changes in V28 Summary 

  • HCCs increased from 86 to 115, reflecting updated clinical classification 

  • 2,294 ICD-10-CM codes removed from contributing to RAF 

  • 268 new codes added, 40% related to perinatal and congenital categories 

  • Conditions with inflated RAFs in V24 (e.g., Protein Calorie Malnutrition, T2DM without complications) have been reduced or removed 

🧱 Implications for Providers and MAOs 

  • Precise, compliant ICD-10-CM coding is now mission critical 

  • Provider documentation must clearly support code selection and demonstrate condition severity 

MAOs must: 

  • Expand chart review programs 

  • Strengthen clinical documentation improvement (CDI) initiatives 

  • Integrate model-specific education for coding teams 

  • Financial impact will vary based on member case mix, provider readiness, and coding accuracy 

✅ Final Word 

CMS-HCC V28 transforms how Medicare Advantage risk scores are derived. With increased specificity, updated mappings, and new RAF logic, the model rewards accurate, clinically supported documentation. 

Plans and providers who start preparing now will not only ensure compliance, but also protect risk-adjusted revenue in 2024, 2025, and beyond.