Comparison of time courses of area coverage of platelets adhering to vWF- and collagen-coated surfaces. Values for the percentage of area covered by fluorescent platelets were plotted as a function of the time after the start of blood flow. Adhesion was observed under flow rates of 200/s (▪), 400/s (▴), 800/s (▾), 1,600/s (♦), and 3,200/s (•). Adhesion on the collagen-coated surface increased biphasically, but adhesion on the vWF-coated surface increased linearly.