Shear-dependent PS exposure and microvesiculation are tightly coupled. Thrombin-stimulated mouse (0.2 U/mL) and human (10 U/mL) platelets were subjected to shear or thrombin alone or thrombin + shear and analyzed for PS exposure (Annexin V binding) and MV release using flow cytometry. (A) Histograms showing Annexin V binding and gating of events with high (G1), intermediate (G2), and baseline (G3) fluorescence intensity. (B-C) SSC vs FSC density plots showing the light scatter characteristics of the ungated and gated events from either (B) mouse or (C) human platelets. (D) Quantification of platelets and MVs that were within G1, G2, and G3 gates (mean ± SEM, n = 3 for mouse, n = 5 for human).