Clinical performance of anticardiolipin and antiβ2 glycoprotein I antibodies using a new automated chemiluminescent assay: superior thrombotic prediction of combined results measured by two different methods.

The anticardiolipin (aCL) and antibeta2-glycoprotein I (aβ2GPI) antibodies are used to diagnosis antiphospholipid syndrome. It would be possible to use two or more methods to improve the diagnostic sensitivity of aCL and aβ2GPI. In this study, we investigated the laboratory performance of a new chemiluminescent assay and explored whether the combined results of aCL and aβ2GPI measured by two different methods predict thrombotic risk better. The cut-off values were assessed with 99 healthy controls. The coefficient of variations was determined using control materials. Using the plasma of 109 patients, AcuStar chemiluminescent assay and QUANTA Lite ELISA were carried out according to the manufacturers' instructions. The AcuStar cut-off points were 13.5 U/ml for aCL IgG, 19.1 U/ml for aCL IgM, 16.3 U/ml for aβ2GPI IgG and 12.6 U/ml for aβ2GPI IgM. Total coefficient of variations ranged from 4.6 to 8.8%. For both aCL and aβ2GPI, the AcuStar odds ratio for thrombosis prediction was higher than that of QUANTA Lite. When the results for both AcuStar and QUANTA Lite are positive, the odds ratios of aCL and aβ2GPI were higher than that interpreted by a single positive result each. The new automated chemiluminescent assay exhibited good precision, concordance rate, and clinical performance. The combined results of aCL and aβ2GPI as measured by two different methods are expected to increase the prediction power for thrombosis.