SEM-images of fibrin clots.

(A) Normal fibrin clots as control. (B) Clot formed from the patient's fibrinogen after 45 minutes of incubation with thrombin showing thin fibers forming a secondary network of spongelike structure. (C,D) Clots formed after 17 hours of incubation with thrombin, showing large pores bounded by smaller secondary, highly branched lacelike networks. Bar, 2 μm.