[Lupus anticoagulant screening: comparison of 5 tests (author's transl)]

Five tests were carried out on 15 lupus anticoagulant plasmas: activated partial thromboplastin time with a commercial reagent (APTT); kaolin partial thromboplastin time with a human brain extract (KPTT-H); tissue thromboplastin inhibition test (TTI); Russell's viper venom time without phospholipid (RVVT); assay of phospholipid-related procoagulant activity (PPA). One of our criteria for diagnosis of lupus anticoagulant was a prolonged APTT; hence this test was abnormal in all 15 plasmas. An abnormal TTI was observed for the 15 lupus anticoagulants while PTT-H was abnormal in only 13 cases, RVVT in 11 cases and PPA assay in 12 cases. In another study evaluating the specificity of TTI and PPA assay, the TTI appeared to be influenced by factor II, V, VII, and X deficiencies, but not by factor VIII: C, IX, XI, and XII deficiencies, or by anti-factor VIII: C anticoagulants. Furthermore, the TTI displayed a weak sensitivity to heparin. On the other hand, the PPA assay was influenced by anti-factor VIII: C anticoagulants of high potency and was found to be more sensitive to heparin than the TTI. Our overall results emphasize the value of TTI as a screening test for the lupus anticoagulant.