INOSITHIN NEUTRALIZATION TEST TO MEASURE LUPUS ANTICOAGULANTS

The inosithin neutralization test was performed in 14 patients in whom lupus anticoagulant was detected. To test its specificity, it was also performed in 10 patients with severe hemophilia and in three patients with Factor VIII inhibitors. Prolonged kaolin clotting time was corrected by adding varying amounts of inosithin (Asolectin, 0.19 to 100 mug), a soybean-derived phospholipid, in all patients with lupus anticoagulant but not in patients with hemophilia or in two patients with Factor VIII inhibitors. In one patient, both Factor VIII inhibitors and lupus anticoagulant were present. The concentration of lupus anticoagulant in a patient was expressed as the amount of inosithin (measured in micrograms) required to normalize the prolonged kaolin clotting time. This amount correlated significantly with the occurrence of thrombosis and/or recurrent abortion. The inosithin neutralization test is useful to measure lupus anticoagulant.