title: Diluted Russell viper-venom time improves identification of antiphospholipid syndrome in a lupus anticoagulant-positive patient population.
abstract: The objective of this retrospective study was to evaluate the potential ability of diluted Russell viper-venom time (dRVVT) to identify antiphospholipid syndrome (APS) in a lupus anticoagulant (LA)-positive patient population, already selected by other LA clotting tests. Our cohort of positive LA patients was first identified in our outpatients population by the following sensitive LA-detecting tests: Rosner index, diluted prothrombin time (dPT) and Rosove index. Then the 227 consecutive LA-positive patients were tested for dRVVT with the same blood sample. Anticardiolipin (aCL) and anti-beta(2)-glycoprotein-I (beta(2)GPI) autoantibodies assays were also performed. APS using Sapporo clinical criteria revised at Sydney, was found in 116 of these 227 consecutive LA-positive patients. Results of the different tests were analysed statistically. Using univariate analysis, dRVVT, dPT, IgG aCL and IgG anti-beta(2)GPI autoantibodies were significantly associated with APS. The receiver operating-characteristics (ROC) curve defined the best cut-off value for dRVVT ratio at 1.61 with a good specificity (78%) and a lower sensitivity (53%). A multivariate analysis using a binary logistic procedure, retained the dRVVT ratio (> or = 1.61) and IgG anti-beta(2)GPI autoantibodies (> 15 USG) as being associated with APS (p = 0.018; odds ratio [OR] 2.39; 95% confidence interval [CI] 1.2-4.7, and p = 0.0001; OR 3.2; 95% CI 1.5-6.5, respectively). To conclude, these results agree with the need for LA criteria favouring specificity over sensitivity. The use of a threshold around 1.6 for dRVVT ratio should help discriminate APS from non-APS patients.
authors.affiliation: Internal Medicine Department, CHRU Lille, Huriez Hospital, rue Polonovski, 59035, Lille Cedex, France. m-lambert@chru-lille.fr
authors.forename: Marc
authors.initials: M
authors.lastname: Lambert
authors.forename: Gisele
authors.initials: G
authors.lastname: Ferrard-Sasson
authors.forename: Sylvain
authors.initials: S
authors.lastname: Dubucquoi
authors.forename: Eric
authors.initials: E
authors.lastname: Hachulla
authors.forename: Lionel
authors.initials: L
authors.lastname: Prin
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Hatron
authors.forename: Jenny
authors.initials: J
authors.lastname: Goudemand
authors.forename: Marie-Claire
authors.initials: MC
authors.lastname: Boffa
authors.forename: Claudine
authors.initials: C
authors.lastname: Caron
mesh_terms: D000328:Adult; D016736:Antiphospholipid Syndrome / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D001780:Blood Coagulation Tests / Q000379:methods*; D005260:Female; D006801:Humans; D007155:Immunologic Factors / Q000097:blood* / Q000276:immunology; D016682:Lupus Coagulation Inhibitor / Q000097:blood* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D014757:Viper Venoms
chemical_list: D007155:Immunologic Factors; D016682:Lupus Coagulation Inhibitor; D014757:Viper Venoms