In vitro fibrinogen binding. Whole blood was drawn into citrate from a retro-orbital sinus of anesthetized animals. Whole blood was stimulated with 10μM ADP, 1 U/mL thrombin, or 1mM MnCl₂ and then incubated with Oregon green-fibrinogen for 20 minutes at room temperature. FL1 was read using a FACScan (BD Biosciences). Results are shown for blood from hTg^WT animals (black line) and hTg^G233V animals (gray line) without agonist or in the presence of ADP, thrombin, or MnCl₂. hTg^G233V platelets are severely impaired in their ability to respond to either ADP or thrombin.