The shift to CMS’s updated risk adjustment model, HCC Version 28 (V28), has officially taken hold in 2025. Although the payment model won’t be fully implemented until 2026, the diagnoses captured this year will directly affect future reimbursement—making 2025 a critical turning point for Medicare Advantage organizations.
Why the Transition to V28?
CMS designed the new model to improve accuracy in how patient complexity is measured. V28 is based on more current data and ICD-10 code sets, reflecting real-world clinical patterns and treatment costs more effectively than its predecessor, V24.
While the number of HCC categories increased from 86 to 115, the total number of ICD-10 codes that map to HCCs dropped by about 20 percent. Many diagnoses that previously impacted risk scores—especially those that are well-controlled, temporary, or less predictive of cost—no longer count. In contrast, a smaller set of newly emphasized chronic conditions and severity-specific codes have become more important than ever.
What’s Out, What’s In
Conditions removed from HCC mapping include stable angina, mild or remission-stage mental health conditions, uncomplicated substance use disorders, and some acute or post-procedural conditions. These were deemed to have limited impact on future healthcare costs.
In their place, the model now emphasizes high-cost and high-severity conditions. Examples include severe persistent asthma, advanced-stage heart failure, specific stages of chronic kidney disease, and newly recognized rare diseases. Several existing HCCs were also subdivided by severity, reinforcing the need for detailed documentation.
Coding in 2025: All V28, All the Time
Even though reimbursement in 2025 still reflects a blend of V24 and V28, only V28-mapped codes count for risk scoring going forward. This means provider documentation must align with the new mapping now—no exceptions.
Organizations that have not yet adapted to the model’s specificity requirements may see unexpected declines in RAF scores, even if patient acuity hasn’t changed. The resulting revenue dip is by design; CMS is recalibrating payments to match true risk and reduce historical overpayments. But without careful documentation and diagnosis capture, the financial impact could be greater than necessary.
Meeting the Moment with Precision
Success under V28 requires updated workflows, strong clinical documentation, and a renewed focus on diagnostic accuracy. Education around new HCC requirements—particularly when it comes to staging, severity, and specificity—is essential. So is integrating coding support and review processes that catch underreported conditions.
Looking Ahead
The V28 model challenges providers and health plans to step up their documentation game, but it also presents a valuable opportunity. By improving the quality and accuracy of condition capture, organizations can ensure patients’ true complexity is reflected—supporting better care coordination and appropriate reimbursement.
The bottom line: RAF scores may be leaner under V28, but they’re also more accurate. The organizations that will thrive in this environment are those that document smarter, adapt quickly, and invest in sustainable coding practices that align with the reality of today’s value-based care landscape.
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