Thrombin itself is impossible to quantitate because it lasts only seconds in the blood circulation. Thus, it is necessary to use a surrogate marker. This peptide is released into the plasma and has a half life of 90 minutes, compared to the half life of thrombin which is 30 seconds. As thrombin is generated, natural inhibitors attempt to prevent clot formation by complexing with thrombin to remove it from the circulation. Thus, in a compensated system, small amounts of thrombin are removed appropriately.
Elevated TATs indicates thrombin generation and an attempt to remove excess thrombin.
With the consumption of fibrinogen, the body may compensate by increasing fibrinogen levels slightly above the normal range. Elevated SFM levels increases blood viscosity, is seen as fibrin deposition on endothelial cells in the micro-circulation, and lead to chronic illnesses. When there is a burst of Thrombin, Factor XIII is activated to XIIIa, which crosslinks SFM into insoluble cross-linked fibrin strands, leading to a blood clot. Increased SFM indicates that the normal removal of thrombin is saturated or no longer working properly and that there is enough activation of the clotting mechanism to generate fibrin or potentially form a blood clot, ie, the hypercoagulable or prethrombotic state. They can be ordered through any hospital or on an outpatient basis.