Variability and diagnostic utility of antiphospholipid antibodies including lupus anticoagulants

Summary Antiphospholipid antibodies (a PL ) comprise a heterogeneous group of antibodies directed against phospholipids and/or protein‐complexed phospholipids. a PL are associated with the serious autoimmune condition ‘antiphosholipid (antibody) syndrome’ ( APS ) and can be defined by either ‘solid‐phase’ assays that identify anticardiolipin antibodies (a CL ) and anti‐β2‐glycoprotein I antibodies (a B 2 GPI ) or ‘liquid‐phase’ assays that identify lupus anticoagulants ( LA s). There is a lack of standardization associated with all forms of a PL testing; however, intermethod and interlaboratory variation using a CL and a B 2 GPI assays is generally higher than that for LA testing by d RVVT (dilute russell viper venom time) procedures. Compared with either a CL or a B 2 GPI , LA is also more strongly associated with clinically adverse findings of APS , including thrombosis and obstetric morbidity. This review explores the potential reasons for the above findings and concludes that ultimately a more holistic approach to a PL / APS investigations is needed.