Lupus anticoagulant 2017-02-12T13:19:32Z Presence of lupus anticoagulant (LA) autoantibodies. LA represent a heterogeneous group of autoantibodies, IgG, IgM, or a mixture of both classes, that interfere with standard phospholipid-based coagulant tests (this is only an in vitro phenomenon, LA do not cause reduction of coagulation in vivo). The antibodies are directed against plasma proteins which also bind to phospholipid surfaces. Most individuals with lupus anticoagulant do not have lupus erythematosus or other systemic autoimmune disorders. One of the tests for lupus anticoagulant is the dilute Russell's viper venom time (dRVVT). Autoimmune antibody positivity