A rapid screen for lupus anticoagulant with good discrimination from oral anticoagulants, congenital factor deficiency and heparin, is provided by comparing a sensitive and an insensitive APTT reagent - Brancaccio,V.; Ames,P.R.; Glynn,J.; Iannaccone,L.; Mackie,I.J. (Blood Coagul Fibrinolysis, 1997)