Common measures describing fibrin clot structure and function. A key measure reflecting an average pore size within a fibrin network, based on hydraulic conductivity is clot permeability or permeation (K_s; panel A). Q denotes the flow rate; L, the length of a fibrin gel; µ, the viscosity of liquid (in poise); A, the cross-sectional area (in cm²), Δp, a differential pressure (in dyne/cm²), and t the percolating time. Reduced K_s as a typical feature of the prothrombotic fibrin clot phenotype is usually associated with lower fibrin fibre diameter, lower pore size, and increased number of fibrin branch points visualized using confocal (panel B) and scanning electron microscopy (panel C). Faster fibrinogen polymerization results in the formation of a denser fibrin network (higher clot turbidity), which is relatively resistant to fibrinolysis as reflected by prolonged clot lysis time (CLT; panel D), or real-time clot lysis assessed using confocal microscopy (panel E).