[Usefulness of silica clotting time for detection of lupus anticoagulants].
BACKGROUND
The presence of lupus anticoagulants (LA) is a strong risk factor for thrombosis in antiphospholipid syndrome. We investigated the usefulness of addition of silica clotting time (SCT) to the pre-existing dilute Russell's viper venom test (dRVVT) for detection of LA. Also, we analyzed differences in the thrombotic features and the characteristics of antiphospholipid antibodies between dRVVT and SCT.


METHODS
A total of 167 patients positive for LA or anti-cardiolipin (anti-CL) antibody and 76 healthy controls were enrolled. The dRVVT and SCT were used for detection of LA. Anti-CL, anti-beta2-glycoprotein I (anti-beta2 GPI) and anti-prothrombin (anti-PT) antibodies were measured using commercial ELISA kits.


RESULTS
In detection of thrombosis, the sensitivity of the combined test of SCT and dRVVT was 56.4%, which was higher than that of dRVVT alone (46.2%) or SCT alone (23.1%). The specificity of the combined test (80.9%) was comparable to that of dRVVT (81.9%). Also, odds ratio for predicting thrombosis was higher in the combined test than in dRVVT or SCT alone. When normalized LA ratio of the two tests was compared, the group of patients with higher ratio of SCT showed significantly higher prevalence of recurrent abortion and higher positivity of IgG types of anti-CL, anti-beta2 GPI and anti-PT than the group with higher ratio of dRVVT.


CONCLUSIONS
Addition of SCT to dRVVT can improve the detection sensitivity of thrombosis in LA test. And the high normalized LA ratio of SCT may be a useful parameter for detection of recurrent abortion.
Lee
Hye Ryun
HR
Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Korea.
Kim
Ji-Eun
JE
Ha
Soo-Hyun
SH
Kim
Hyun Kyung
HK
Park
Seonyang
S
Cho
Han-Ik
HI
D000328:Adult; D000368:Aged; D017153:Antibodies, Anticardiolipin / Q000032:analysis; D017152:Antibodies, Antiphospholipid / Q000032:analysis; D001780:Blood Coagulation Tests / Q000379:methods*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D016682:Lupus Coagulation Inhibitor / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011516:Prothrombin / Q000276:immunology; D011517:Prothrombin Time / Q000379:methods; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide / Q000737:chemistry*; D013927:Thrombosis / Q000175:diagnosis; D053482:beta 2-Glycoprotein I / Q000276:immunology
D017153:Antibodies, Anticardiolipin; D017152:Antibodies, Antiphospholipid; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D016682:Lupus Coagulation Inhibitor; D011933:Reagent Kits, Diagnostic; D053482:beta 2-Glycoprotein I; D012822:Silicon Dioxide; D011516:Prothrombin