Sensitivity of assay to P2Y₁₂ inhibition. Pretreatment of whole blood with the P2Y₁₂ receptor blocker PAM (3 μM) inhibited the platelet response to (A) 1 μg/mL collagen, (B) PAR4-AP, or (C) U46619. Data reported as mean ± SEM (n = 6). *P < .05 by 2-way ANOVA vs vehicle (0.5% DMSO).