Real-world evidence of lupus anticoagulant testing: simultaneous positivity of diluted Russell's viper venom time and silica clotting time increases thrombotic risk prediction

Abstract

Lupus anticoagulant (LA) is composed of heterogeneous autoantibodies, which have a close association with thrombotic events. Due to its heterogeneity, two methods for increasing sensitivity are recommended for LA. An investigation of the thrombotic risk and anticardiolipin (aCL) and anti-beta 2-glycoprotein I (aB2GPI) antibody profiles was conducted based on the results of using two parallel methods (dilute Russell viper venom time (dRVVT), silica clotting time (SCT)) in a real world clinical laboratory. Of 5120 patients, 684 patients (13%) were LA positive, and 422 patients (8%) experienced thrombotic events including pregnancy complication. Development of thrombotic events was more likely to occur in patients who were positive for both dRVVT and SCT compared with those who were positive for dRVVT or SCT only. In addition, significantly higher positive rates of aCL and aB2GPI and the persistently positive rate of LA at intervals of 12 weeks or longer were observed in patients who were positive for both dRVVT and SCT compared with those who were positive for dRVVT or SCT only. Considering three laboratory tests (LA, aCL, and aB2GPI), high thrombotic risk was observed for patients with both dRVVT and SCT positive LA results. A report on LA results that divides LA positive into two types (LA-single positive and LA-both positive) may be beneficial to clinicians in detection of high-risk thrombotic patients.