Open AccessUse of a new silica clotting time for diagnosing lupus anticoagulant in patients who meet the clinical criteria for antiphospholipid syndrome
Author(s) -
Grypiotis Panagiotis,
Ruffatti Amelia,
Pengo Vittorio,
Tonello Marta,
Biasiolo Alessandra,
Zamboni Daniela,
Cavazzana Anna,
Todesco Silvano
Publication year - 2006
Publication title -
journal of clinical laboratory analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 50
eISSN - 1098-2825
pISSN - 0887-8013
DOI - 10.1002/jcla.20093
Subject(s) - lupus anticoagulant , medicine , antiphospholipid syndrome , partial thromboplastin time , gastroenterology , odds ratio , confidence interval , thrombosis , coagulation
The silica clotting time (SCT) is a phospholipid‐dependent coagulation assay used for the laboratory diagnosis of lupus anticoagulant (LA) antibodies. The sensitivity and specificity of a new commercial SCT for identifying LA in patients who meet the clinical criteria for antiphospholipid syndrome (APS), and its association with thrombotic events were evaluated here. Forty‐five patients who met the clinical criteria for APS according to the Sapporo International Consensus Statement were examined. Sixty‐nine patients who did not meet the clinical criteria for APS, and 20 blood donors were used as controls. Plasma samples from the patients and controls were tested for LA using a new commercial SCT with low and high synthetic phospholipid concentrations. The results were compared with those obtained by diluted Russell's viper venom time (dRVVT) and activated partial thromboplastin time (APTT). SCT's sensitivity for identifying LA in patients who met the clinical criteria of APS was higher compared to APTT and dRVVT (53.3% vs. 31.1% and 31.1%), and the specificities of these assays were 96.6%, 100%, and 98.9%, respectively. When dRVVT was combined with SCT, and dRVVT was combined with APTT their sensitivities were 57.7% and 48.8%, and their specificities were 96.6% and 98.9%, respectively. A stepwise logistic regression analysis indicated that the combination of dRVVT with SCT was associated with total thrombotic events (odds ratio (OR)=11.5, 95% confidence interval (CI)=1.25–106.3, P =0.031) as well as with venous thrombosis (OR=4.09, 95% CI=1.16–14.43, P =0.028). According to our results, SCT is the most sensitive assay for identifying LA in patients who meet the clinical criteria for APS. Moreover, the highest sensitivity was reached with a combination of SCT and dRVVT. The method's association with total thrombotic events and venous thrombosis was in fact significant. J. Clin. Lab. Anal. 20:15–18, 2006. © 2006 Wiley‐Liss, Inc.