November 25, 2025
The Centers for Medicare and Medicaid Services (CMS) is implementing significant changes to the HCC risk adjustment model, transitioning from v24 to v28. This phased transition is reshaping how diagnoses are mapped to HCC codes, how RAF scores are calculated, and ultimately how Medicare Advantage and ACO organizations are reimbursed.
The v28 model introduces several major changes. Many existing HCC codes are being consolidated or eliminated, reducing the total number of payment HCCs. New codes are being added to reflect evolving clinical understanding. Coefficient values are being recalibrated, meaning that the same diagnosis may generate different reimbursement under the new model.
For ACOs and Medicare Advantage plans, these changes have immediate financial implications. Organizations that have optimized their coding practices around the v24 model may see shifts in their RAF scores — some positive, some negative. The transition demands a comprehensive reassessment of risk adjustment strategies.
AI-powered risk adjustment tools are uniquely positioned to help organizations navigate this transition. Machine learning models can be rapidly updated to reflect new HCC mappings, identify documentation opportunities under the v28 framework, and quantify the financial impact of coding changes across the entire patient population.
Organizations should begin preparing now by conducting gap analyses between v24 and v28 coding, training clinicians on new documentation requirements, and implementing AI tools that automate condition capture under the evolving framework. Those who adapt proactively will maintain or improve their financial position through the transition.