Although the value of pharmacogenetic testing and comprehensive gene-based medication management is being recognized by clinicians, it is still not endorsed by many expert committees and third party payers for most prescription drugs. The purpose of this study is to meet the need for evidence that better demonstrates the impact of such comprehensive gene-based medication management on healthcare resource utilization (HRU), clinical decision-making, and patient outcomes. Therefore, the proposed study aims to assess the impact of the YouScript Personal Prescribing System on HRU, clinical decision-making, and clinical outcomes.