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How is an HCC determined?

  • The CMS-HCC diagnostic classification system begins by classifying all ICD-10-CM diagnosis codes into diagnostic-related groups (DRG), which represent well-specified medical conditions or sets of conditions. Each code maps to a single DRG. DRGs are further aggregated into Condition Categories (CC), which describe a broader set of similar diseases. CCs are related clinically and with respect to cost. Hierarchies are imposed among related CCs, so that a person is coded for only the most severe manifestation among related diseases. After imposing hierarchies, CCs become Hierarchical Condition Categories (HCC). Because HCCs accumulate, a single individual may be coded for none, one, or more than one HCC.