Korean J Lab Med.  2009 Dec;29(6):497-504. 10.3343/kjlm.2009.29.6.497.

Usefulness of Silica Clotting Time for Detection of Lupus Anticoagulants

• Lee HR
• Kim JE
• Ha SH
• Kim HK
• Park S
• Cho HI

• KMID: 1781601
• DOI: http://doi.org/10.3343/kjlm.2009.29.6.497

Abstract

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.

Keyword

Dilute Russell's viper venom test (dRVVT); Silica clotting time (SCT); Antiphospholipid antibody; Antiphospholipid syndrome; Vascular thrombosis; Pregnancy morbidity

MeSH Terms

Adult
Aged
Antibodies, Anticardiolipin/analysis
Antibodies, Antiphospholipid/analysis
Blood Coagulation Tests/*methods
Female
Humans
Immunoglobulin G/analysis
Immunoglobulin M/analysis
Lupus Coagulation Inhibitor/*blood
Male
Middle Aged
Prothrombin/immunology
Prothrombin Time/methods
Reagent Kits, Diagnostic
Sensitivity and Specificity
Silicon Dioxide/*chemistry
Thrombosis/diagnosis
beta 2-Glycoprotein I/immunology