Comparison of Two Point-of-Care CYP2C19 Genotyping Assays for Genotype-Guided Antiplatelet Therapy.

BACKGROUND: CYP2C19 polymorphisms contribute about 12% of the variability in the antiplatelet effect of clopidogrel, which is commonly prescribed for patients undergoing percutaneous coronary intervention. For these patients, rapid turnaround time of CYP2C19 genotyping may be critical. We validated and compared the performance of two point-of-care CYP2C19 genotype tests, Nanosphere Verigene CYP2C19 Nucleic Acid Test and Spartan RX CYP2C19 System. MATERIALS AND METHODS: Our CLIA certified Molecular Diagnostic Laboratory performed 99 Verigene tests and 108 Spartan RX CYP2C19 assays. We compared performance and genotype results between the two platforms, across runs, and among technologists. Based on our validation results, we started offering CYP2C19 genotyping using the Spartan RX CYP2C19 assay for post-percutaneous coronary intervention patients. RESULTS: Laboratory validation genotype results were consistent between both assays when the assays produced results (100% accuracy); however, the Verigene CYP2C19 had a 33% no call rate. In contrast, Spartan consistently showed accurate results. Using a newly established clinical workflow, we assayed 342 post-percutaneous coronary intervention patients with the Spartan test. Within one hour of submitting patient samples, ordering physicians were notified of any clinically significant results and provided clinical decision support. CONCLUSIONS: Every approach has its limitations, but our practice of using the Spartan RX CYP2C19 test in our acute cardiac workflow provides accurate and rapid results to guide clinical decision-making at the point-of-care. Prospective follow-up is ongoing to evaluate outcomes and effectiveness of CYP2C19 testing.