Equilibrium shrinkage of a fibrin clot containing RBCs in the presence of increasing concentrations of 100 kDa dextran. Prediction from continuum theory is shown together with experimental data for both cross-linked and uncross-linked fibrin clots containing RBCs. The overall trend of increasing contraction with increasing dextran concentration is captured by a theory that accounts for depletion and electrostatic interactions in addition to fibrin clot elasticity, RBC bridging interactions, and RBC-fibrin adhesion.