The purpose of the Beta 2 Glycoprotein 1 Antibody (B2GP1) IgM test is to detect the presence of IgM antibodies against beta-2 glycoprotein 1 (B2GP1), a plasma protein. These antibodies are often associated with autoimmune disorders, particularly antiphospholipid syndrome (APS), a condition that can lead to the formation of blood clots (thrombosis) in the body.