Activation of the coagulation process will lead to the cleavage of fibrinogen to fibrin. The fibrin molecule that results will be cross-linked via D-domain by Factor XIII, producing a stable fibrin clot. Exacerbation of this process can lead to major clot and thrombi formation, which, if not controlled, can be fatal. Activation of the fibrinolytic system results in the conversion of plasminogen into the active protease, plasmin. Plasmin cleaves fibrinogen and fibrin into fragments D and E. Plasmin will release fibrin degradation products with cross-linked D-domains, the smallest unit of which is the D-dimer. Thus, detection of D-dimers is an indication of reactive fibrinolysis. Elevated levels of D-dimer is indicative of the presence of a clot and has been reported in certain pathological conditions such as Pulmonary Embolism (PE), Deep Vein Thrombosis (DVT), and Disseminated Intravascular Coagulation (DIC).