Platelets from a patient with Glanzmann thrombasthenia have decreased platelet spreading and platelet-platelet interactions on collagen.

Control platelets (A) and platelets from a patient with Glanzmann thrombasthenia (B) were anticoagulated with ACD, washed twice, and resuspended in HBMT buffer (100 000/μL). Platelets were added to channels in the collagen-coated microchamber, incubated for 60 minutes at 22°C, and analyzed by differential interference microscopy. Control platelets demonstrate platelet-platelet interactions and platelet spreading. The patient's platelets demonstrate few platelet-platelet interactions, a relatively uniformly scattered pattern of platelet deposition, and less platelet spreading. Scale bars represent 10 μm.