HCC coding determines how much Medicare pays for your patients. Here's everything medical coders and providers need to know about Hierarchical Condition Categories, RAF scores, and risk adjustment.
HCC stands for Hierarchical Condition Category. HCC coding is a risk adjustment methodology used by the Centers for Medicare & Medicaid Services (CMS) to calculate how much Medicare Advantage plans are paid for each enrollee.
In plain terms — HCC coding tells Medicare how sick your patients are. Sicker patients cost more to treat, so Medicare pays more for them. HCC coding is how that calculation happens.
Every ICD-10-CM diagnosis code maps to one of approximately 86 HCC categories under the current CMS-HCC Model V28. Each HCC category carries a Risk Adjustment Factor (RAF) score that determines its payment weight.
Key Insight: HCC coding is not just a billing function — it directly determines Medicare Advantage plan revenue. Accurate and complete HCC coding can mean hundreds of thousands of dollars in recovered or at-risk revenue for a health plan or provider organization.
The HCC risk adjustment process works like this:
The average Medicare Advantage enrollee has a RAF score around 1.0. A healthier patient might score 0.5 while a patient with multiple chronic conditions could score 3.0 or higher.
The Risk Adjustment Factor (RAF) score is the numeric value assigned to each HCC category. A RAF score of 1.0 means average cost. A score of 2.0 means the patient is expected to cost twice as much as average.
| RAF Score Range | Severity | Example Conditions |
|---|---|---|
| 1.0+ | High impact | Respirator dependence (1.974), Metastatic cancer (2.659), Quadriplegia (1.233) |
| 0.2 – 0.49 | Moderate impact | CHF (0.323), COPD (0.326), CKD Stage 5 (0.289), Schizophrenia (0.444) |
| < 0.2 | Lower impact | Diabetes without complications (0.105), Angina (0.096) |
CMS-HCC Model V28 is the current model effective for payment year 2026. Key changes from prior models include reorganized HCC categories, updated RAF scores, refined diabetes HCC hierarchy, and some codes removed from the model.
Important: CMS transitioned from V24 to V28 over three years (2024–2026). For 2026, V28 is fully in effect. Always verify your HCC references use V28 data, not the older V24 mappings.
| HCC | Category | RAF Score | Common Codes |
|---|---|---|---|
| HCC17 | Diabetes without Complication | 0.105 | E11.9, E10.9 |
| HCC18 | Diabetes with Chronic Complications | 0.302 | E11.21, E11.40, E11.51 |
| HCC85 | Congestive Heart Failure | 0.323 | I50.9, I50.20–I50.43 |
| HCC111 | COPD | 0.326 | J44.0, J44.1, J44.9 |
| HCC137 | CKD Stages 3–4 | 0.118 | N18.3, N18.4 |
| HCC136 | CKD Stage 5 / ESRD | 0.289 | N18.5, N18.6 |
| HCC96 | Specified Heart Arrhythmias | 0.175 | I48.0, I48.11, I48.91 |
| HCC58 | Major Depressive/Bipolar Disorders | 0.309 | F32.9, F33.0, F31.9 |
Medicare Advantage plans receive capitated payments from CMS based on the RAF scores of their enrolled population. Incomplete HCC coding directly reduces plan revenue.
Value-based contracts increasingly tie provider reimbursement to risk-adjusted quality metrics. Accurate HCC coding ensures providers are fairly compensated for the complexity of their patient population.
Audit Risk: CMS conducts RADV audits to verify HCC coding accuracy. Overcoding carries significant compliance risk including repayment obligations and potential False Claims Act liability.
ICD10Source shows HCC category and RAF score alongside every ICD-10-CM code — completely free. Search any code and instantly see its HCC category and RAF score color-coded by severity level.
The information in this guide is based on official U.S. government publications. Always verify coding information against the most current official sources before use in billing or clinical documentation.
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