Iron alters red blood cell morphology.

Under physiologic conditions a small percentage ( 3%) of red blood cells (RBCs) are irreversibly trapped within the fibrin clot mesh. By contrast, in prothrombotic states such as diabetes mellitus, significantly more RBCs are tightly bound to fibrin fibers. Such interactions affect clot properties, making it more resistant to fibrinolytic degradation. This phenomenon may explain thrombolytic resistance frequently seen in diabetic patients. In most cases these patients also have higher-than-usual levels of iron.