Coagulation tests and anti-phospholipid antibodies in patients positive for lupus anticoagulant

We examined activated partial thromboplastin time, kaolin clotting time, mi xing with normal plasma in kaolin clotting time, dilute Russell's viper ven om time, dilute Russell's viper venom time at high lipid concentrations, an tiphospholipid antibodies, and anti-cardiolipin-beta 2-glycoprotein I compl ex antibody in 135 patients with prolongation of activated partial thrombop lastin time and diagnosed 86 patients positive for lupus anticoagulant. The sensitivity of activated partial thromboplastin time and dilute Russell's viper venom time/dilute Russell's viper venom time-high lipid concentration s ratio for lupus anticoagulant were markedly high, but the specificity of activated partial thromboplastin time for lupus anticoagulant was not marke dly high. The specificity, but not the sensitivity, of kaolin clotting time -mixing with normal plasma in kaolin clotting time was markedly high. In su mmary, dilute Russell's viper venom time to dilute Russell's viper venom ti me-high lipid concentrations ratio gave high sensitivity as well as specifi city, being the only assay to confirm this. Of the patients positive for lu pus anticoagulant, 25% were positive for anti-phospholipid antibodies and 1 7% were positive for anti-cardiolipin-beta 2-glycoprotein I complex antibod y. Of the lu pus anticoagulant-positive patients with thrombosis, 35% were positive for anti-phospholipid antibodies, 35% were positive for anti-cardi olipin-beta 2-glycoprotein I complex antibody, 60% were positive for both a nti-phospholipid antibodies and anticardiolipin-beta 2-glycoprotein I compl ex antibody, and only 17% were negative for anti-phospholipid antibodies an d anticardiolipin-beta 2-glycoprotein I complex antibody. These findings su ggest that lupus anticoagulant can be diagnosed by dilute Russell's viper v enom time/dilute Russell's viper venom time-high lipid concentrations ratio , and that thrombosis in lupus anticoagulant-positive may be predictable fr om both anti-phospholipid antibodies and anti-cardiolipin-beta 2-glycoprote in I complex antibody. Plasma tissue type plasminogen activator level in lu pus anticoagulant patients was significantly increased, and plasma tissue t ype plasminogen activator and fibrin-D-dimer levels in lupus anticoagulant- positive patients with thrombosis were significantly higher than in those w ithout thrombosis suggesting that the diagnosis of thrombosis by hemostatic markers might be important in lupus anticoagulant.