PAR-1 density on human platelets.

PAR-1 density was determined on resting platelets from 100 healthy volunteers by quantitative flow cytometry using mAb WEDE15 directed against both cleaved and intact PAR-1. The number of PAR-1 receptors at visit 1 (y-axis) is plotted against the number at visit 2 (x-axis), and shows significant concordance (r² = 76%,P < .001). Values ranged from 804 to 1713 sites/platelet (mean, 1262 ± 198 sites/platelet).