Thrombotic risk assessment and analytical performance of the chemiluminescent analyzer IDS-iSYS for the detection of anti-cardiolipin and anti-beta 2 glycoprotein I autoantibodies

Patients with antiphospholipid antibodies (APLA) are predisposed to develop thrombosis, however the standardization of anti-cardiolipin (aCL) and anti-beta 2 glycoprotein I (β2-GPI) Ab assays are challenging. Therefore we decided to test the performance of a new chemiluminescent assay (CLIA), and assayed aCL and aβ2-GPI IgG/M in serum from 120 healthy individuals, 108 patients with idiopathic venous thrombosis, 78 patients with antiphospholipid syndrome (APS), and 64 non-thrombotic APLA-carriers using CLIA IDS-iSYS. Very good (aCL/aβ2-GPI IgG) to moderate (aCL/aβ2-GPI IgM) agreement with a commercial and an in house ELISA assay were observed and, in particular, CLIA demonstrated the highest sensitivity in aβ2-GPI IgG detection. Finally, aCL/aβ2-GPI Ab capacity to predict the thrombotic risk was tested showing for CLIA a significant odds ratio (OR) when considering double positivity for aCL/aβ2-GPI IgG, aCL IgG at high levels, and aβ2-GPI IgG at high levels. In conclusion, CLIA improves aβ2-GPI IgG detection and thrombotic risk assessment.