Optimising testing for phospholipid antibodies

Aim—To compare anticardiolipin (ACL) and anti-â2 glycoprotein 1 (â2gp1) enzyme linked immunosorbent assays (ELISAs) in the diagnosis of antiphospholipid syn-drome (APS) and to incorporate these results into a meta-analysis of published data. Method—Three representative commer-cial ACL ELISAs and an in house â2gp1 assay were optimised and then assessed on 124 sera from normal donors, patients with infection, or patients with APS. A Medline search was screened for papers meeting defined criteria to conduct a meta-analysis. The performance of the assays used in this study was included. Results—A non-quantitative ACL assay performed at least as well as the anti-â2gp1 assay in the diagnosis of APS. Meta-analysis confirmed that neither assay is perfect, although the anti-â2gp1 assay had a higher specificity and lower sensitivity than the ACL assay. Conclusions—The pooled data suggest that the ACL assay is used to investigate thrombosis without overt underlying pa-thology and that the improved specificity of the anti-â2gp1 assay is exploited where infection, connective tissue disease, or atheroma are present