Platelet function in response to a single concentration of agonists. Analysis of a single concentration of agonist selected retrospectively to provide optimal capture of variation responses in 50 donors from cohort 1. (A) Variation in fibrinogen binding and P-selectin exposure responses. (B) PCA scree plot demonstrating percentage variability captured by each PC; 85% variability is captured in just 2 PCs. (C) Biplot of first 2 PCs. (D) Heat map resulting from hierarchical clustering response to single concentrations of agonist. Each column represents a response variable, and each row represents a donor. Red cells represent high responders, and blue cells represent low responders. Donors are clustered into 3 groups: high, medium, and low responders. Annotations on the right side indicate the original clusters identified in the main text (Figure 4) that use the sensitivity and capacity metrics, for comparison.