Rather, it serves to inform clinicians of genetic variations in response to clopidogrel and to emphasize that clinicians should use this knowledge to make decisions about how to treat individual patients. At the present time, the evidence base is insufficient to recommend routine genetic testing in patients undergoing PCI. There may be a potential role for genetic testing for patients undergoing elective high-risk PCI procedures (eg, unprotected left main, bifurcating left main, or last patent coronary artery). 6.1.3. Platelet Function Testing: Recommendations Class IIb 1. Platelet function testing may be considered in pa- tients at high risk for poor clinical outcomes.829 (Level of Evidence: C) 2. In patients treated with clopidogrel with high plate- let reactivity, alternative agents, such as prasugrel or ticagrelor, might be considered.829 (Level of Evi- dence: C) Class III: NO BENEFIT 1. The routine clinical use of platelet function testing to screen patients treated with clopidogrel who are undergoing PCI is not recommended.829 (Level of Evidence: C) Platelet function testing to tailor antiplatelet therapy has received considerable interest. The GRAVITAS (Gauging Responsiveness With A VerifyNow Assay-Impact On Thrombosis And Safety) trial and several other ongoing trials test the concept that tailoring antiplatelet therapy based on platelet responsiveness assessed in an ex vivo P2Y12 assay will improve cardiovascular outcomes.830 In GRAVITAS, treatment with high-dose clopidogrel for 6 months in patients with high platelet reactivity on standard-dose clopidogrel was not beneficial. At the present time, the evidence base is insufficient to recommend routine platelet function testing. 