Published guidelines and updates to the U.S. product labeling represent significant advances to our ability to implement pharmacogenomic testing into clinical practice and how to use some this information when it is available. However, information to support whether testing should be completed for gene variants that influence drug metabolism is still lacking. The lack of data examining whether patient care that integrates pharmacogenomic test information for many of these drugs results in better or safer treatment outcomes remain a significant barrier to widespread use and coverage by insurance providers. As of 2012, 8 of 27 reviewed pharmacogenomic tests, including carbamazepine and tetrabenazine, were covered by leading U.S. insurance companies.52 The covered tests included CYP2D6 for tetrabenezine and HLA-B*1502 for carbamazepine. The coverage policies were mostly based on the evidence included in pharmacogenomics guidelines and FDA-approved product labeling. This indicates that as guidelines and labeling increase, so will the likelihood of reimbursement. Certainly, there are many clinical examples that highlight individual instances where using such information has provided knowledge that improved care; however, how testing performs on a larger scale is
