At arterial and venous shear, platelet-dependent fibrin clot size increases as fibrinogen γ′ levels increase within the (patho)physiological range. Following kinetics experiments assessing fibrin deposition, 5 end point images were taken at different locations around the microspot. (A-J) Clots formed under arterial shear (500s⁻¹) and K-T venous shear (150s⁻¹). (A-E,K-O) Experiments carried out using repleted plasma. (F-J,P-T) Experiments carried out using LEADS plasma samples.(A,F,K,P) Representative images of depth-coded z-stack images from above. Images are 213 × 213 μm. (B,G,L,Q) Representative images of depth-coded z-stack images from the side. Images 50 × 213 μm. (C,H,M,R) Total fibrin volume of end point clots. (D,I,N,S) Maximum height of end point clots. (E,J,O,T) Distribution of fibrin represented by area of fibrin per slice vs distance from the clotting surface. Data are mean ± SD. *P < .05, **P < .01, ***P < .001, ****P < .0001, 1-way ANOVA, followed by Tukey’s multiple-comparisons test (C-D,M-N); unpaired Student t test (H-I,R-S).