GPVI deficiency leads to abolished PS exposure under flow. Whole blood from control, GP6^hom, and GP6^het individuals was recalcified and perfused over a collagen surface cocoated with tissue factor. Quantification of surface area coverage (SAC), PS exposure, and fibrin surface area coverage is shown. Data are shown as mean ± SD; control = 4, GP6^het = 3, and GP6^hom = 6. ****P < .0001, **P < .01. Representative bright-field and Alexa Fluor 647-Annexin A5 images taken after 6 minutes of blood perfusion are shown from a control and a GP6^hom subject on a collagen surface. Scale bars, 50 μm.