Both TF and FXII are critical for fibrin accumulation at sites of hemostatic plug formation. (A-D) Platelet (anti–GPIX-AF488) and fibrin (anti–fibrin-AF647) accumulation at injury sites in littermate control (top panel) and TF^low mice (bottom panel). (A) Representative images showing surface view for fibrin ring (blue) around platelet plug (gray). (B) Sum fluorescence intensity (SFI) ± standard error of the mean (SEM) for fibrin signal. (TF^low, n = 15 injuries in 3 mice; and control, n = 14 injuries in 3 mice). (C) SFI ± SEM for platelet signal. (TF^low, n = 15 injuries in 3 mice; and control, n = 11 injuries in 3 mice). (D) Plug density as determined by the ratio between anti-GPIX SFI and plug volume. (TF^low, n = 12 injuries in 3 mice; and control, n = 11 injuries in 3 mice). (E-H) Platelet (anti–GPIX-AF488) and fibrin (anti–fibrin-AF647) accumulation at injury sites in WT (top panel) and F12^−/−mice (bottom panel). (E) Representative images. (F) SFI ± SEM for fibrin signal. (F12^−/−, n = 19 injuries in 4 mice; and WT, n =19 injuries in 3 mice). (G) SFI ± SEM for platelet signal. (F12^−/−, n = 22 injuries in 4 mice; and WT, n = 20 injuries in 3 mice). (H) Plug density. (F12^−/−, n = 22 injuries in 4 mice; and WT, n = 20 injuries in 3 mice). Statistical significance was determined for fluorescence signals of the last 3D stack acquired during the observation period. ns, not significant; ∗P < .05; ∗∗∗P < .001. Scale bar indicates 50 μm.