INTENDED USE The IMUBIND® FSAP ELISA is intended for the measurement of factor seven activating protease in human plasma. The assay is intended for research use only.
EXPLANATION OF THE TEST Factor Seven Activating Protease (FSAP, Factor VII activating protease,FVII activating protease) is a potent activator of factor VII independent of tissue factor and an activator of pro-urokinase. Present in human plasma at a concentration of 12 ug/mL (1 PEU/mL)1, FSAP exists as a singlechain proenzyme with a molecular ratio of 64 kDa. The proenzyme can be activated by an autocatalytic mechanism or by urokinase generating an active two-chain form consisting of a 40 kDa heavy chain and a 30 kDa light chain which possesses the protease domain. The autoactivation is enhanced in the presence of heparin. Conversely, calcium ions stabilize single-chain FSAP and retards the autoactivation.2 FSAP playing a dual role, clot formation via factor VII activation and clot degradation via prourokinase activation, holds a key position in the delicate balance of the hemostatic system.
A mutant variant of FSAP with a single nucleotide polymorphism (SNP) has been identified, termed “Marburg I” (FSAP MI). The FSAP Marburg I variant shows a reduced ability to activate prourokinase, whereas its ability to activate Factor VII is normal.3 It seems likely that FSAP Marburg I, due to the resulting hemostatic imbalance, may promote the development of thromboembolic diseases. The FSAP Marburg I variant was found to have an effect upon the risk for cardiovascular heart disease
in those patients with elevated levels of cholesterol and triglyceride.4 In addition, the FSAP Marburg I variant was found to be a significant risk predictor for the evolution and progression of carotid stenosis5 and associated with idiopathic venous thromboembolism.6