Implementation of pharmacogenomics into the clinical practice of therapeutics: issues for the clinician and the laboratorian.

Pharmacogenomics promises to improve therapeutic care by providing the right drug and dosage to the appropriate patient. Despite widespread interest in personalized medicine, the implementation of clinical pharmacogenomics has been slow. The major issue for clinicians is the lack of evidence that pharmacogenomic testing improves clinical outcomes and that testing is cost-effective. Only a few randomized clinical trials comparing pharmacogenomic testing with standard protocols have been conducted. The few studies that are available have either been underpowered or demonstrated only modest benefits. Nevertheless, if clinical decisions are made regarding therapeutic selection and dosing, pharmacogenomic testing may be justified. Issues for the clinical laboratories (who are responsible for providing pharmacogenomic services) to consider, include the availability of US FDA-cleared tests, the absence of reimbursement codes, the need for genotyping accuracy and the need to find clinical expertise to interpret laboratory results. From the clinical laboratory perspective, testing can be better implemented when these barriers are resolved or minimized. Clinical pharmacogenomics also offers a new field for translational research and teaching at various levels.