Background: Antibodies anticardiolipin (aCL) and anti-β2-glycoprotein I (aβ2GPI) are two of three laboratory criteria of antiphospholipid syndrome (APS). All of assays of antiphospholipid antibodies (aPL), coagulation assays as well as ELISAs, show methodological shortcomings, that affect their sensitivity and specificity. Therefore, we decided to validate these parameters for a new chemiluminescent examination (CLIA).
Methods: aCL and aβ2GPI antibodies were measured by ELISAs (AIDA, Bad Kreuznach, Germany) and aβ2GPI with CLIA kits (Werfen, Barcelona, Spain).
Results: When we evaluated both assays, the coefficient of variation for CLIA was slightly lower (9.04 - 12.74%) than for ELISA (11.05 - 15.3%) and the LOD was 0.2 U/L. The dilution series showed significant linearity for all CLIA methods, aCL IgG, aCL IgM, aβ2GPI IgG, and aβ2GPI IgM (0 - 3000 U/L), and method comparison studies revealed good agreement with the currently used ELISA (Kappa values ranging 0.534 - 0.936) without determination of aβ2GPI IgG. The determination aβ2GPI IgG by CLIA method shows higher positivity in 31 samples. These new aCL IgG, aCL IgM, aβ2GPI IgG, and aβ2GPI IgM tests have excellent analytical characteristics and allow fully automated and simultaneous analysis on an analyzer.
Conclusions: Chemiluminescent determination of an automated analyzer can improve the fundamental parameters of tests such as reproducibility between laboratories.