Detection of phosphatidylserine expression with FITC-labeled annexin V on platelets activated in whole blood by CRP-XL. The annexin V⁺ events comprised a distinct population of platelets, increasing in number dose-dependently. The first and second histograms, from the left, are without CRP-XL and annexin V and without CRP-XL, respectively, and then 0.05, 0.5, 1.0, and 10 μg/mL CRP-XL.