Decoding Pharmacogenomic Test Interpretation and Application to Patient Care

Abstract

Pharmacogenomics is a growing area of medicine, and pharmacists across clinical practice settings have the opportunity to individualize medication selection and dosing using genetic data. However, many practicing pharmacists may feel ill-equipped to interpret pharmacogenomic test results because of insufficient education and training. Evidence-based, updated, and freely available resources such as the Clinical Pharmacogenetics Implementation Consortium guidelines can help pharmacists interpret and apply pharmacogenomic test results to patient care. Although gaps for the application of pharmacogenomic information exist, this commentary aims to demystify the interpretation of pharmacogenomic test results and empower pharmacists to apply genetic data alongside other clinical variables to optimize medication-related outcomes for their patients. An "ABCD" framework is proposed to guide pharmacists through the steps: (1) Actionability - Are the gene(s) clinically relevant for the patient? (2) Be Mindful of Limitations - What are the caveats with pharmacogenomic test results and reports? (3) Clinical Practice Guidelines - How do you use pharmacogenomic test results to guide clinical decision-making? and (4) Document and Discuss - How do you educate the patient about their pharmacogenomic test results and document the results for future use? Key concepts are illustrated using a psychiatric patient case example.

Keywords: CPIC; gene; pharmacist; pharmacogenetics; pharmacogenomics; pharmacy.

Figure 1.

ABCDs of interpreting a pharmacogenomic test.

Figure 2.

Using the CPIC guideline from genotype to phenotype to clinical recommendation. Note the discrepancy in the CYP2C19*1/*17 phenotype between the CPIC guideline and the pharmacogenomic test laboratory report. In addition, note that the alleles tested for CYP2C9 are not comprehensive according to the Association for Molecular Pathology recommendations for alleles to test.