Beta 2-Glycoprotein 1 Screen ELISA is a solid phase enzyme immunoassay employing native _2-glycoproteinI highly purified from human plasma for the combined quantitative and qualitative detection of IgA, IgG and IgM antibodies against _2-glycoprotein I in human serum. Anti-_2-glycoprotein I antibodies recognize specific epitopes on human _2-glycoprotein I which are expressed only when _2-glycoprotein I interacts with lipid membranes or when absorbed to other surfaces (e.g. microtiter plate). The assay is an aid in the diagnosis and risk of primary and secondary antiphospholipid syndrome (APS).