The Beta-2 Glycoprotein 1 IgG test is an automated immunoassay used to detect IgG-class autoantibodies directed against beta-2 glycoprotein 1, a key plasma protein. Elevated levels of these autoantibodies are strongly associated with antiphospholipid syndrome (APS), a systemic autoimmune condition characterized by recurrent arterial or venous thrombosis and adverse pregnancy outcomes. Along with lupus anticoagulant and anticardiolipin antibodies, this test serves as a major diagnostic criterion for APS. Identifying these antibodies helps clinicians stratify thrombotic risk, evaluate unexplained blood clotting events, and guide long-term management and therapeutic anticoagulation strategies for affected patients.