Beta-2 glycoprotein 1 antibodies are most frequently detected in the blood of patients with antiphospholipid syndrome (APS). Current diagnostic criteria for APS are based upon both clinical findings and the persistent presence of one or more antiphospholipid antibodies in the circulation. If a high concentration of beta-2 glycoprotein 1 antibody is detected initially and then again 12 weeks later in a person with signs and symptoms of APS, then it is likely that the person has the disorder. This is especially true if other antiphospholipid antibodies are also detected. This is a confirmatory test, and it is possible to have the antibodies and never have clinical features of APS. Because lots of people are tested with other clinical syndromes, the overall likelihood of having APS with a positive B2GP1 antibody is approximately 32% (i.e. the majority of the patients will have been tested erroneously and will not have APS).. This test detects and measures one or more classes (IgG, IgM, or very rarely IgA) of beta-2 glycoprotein 1 antibodies. Beta-2 glycoprotein 1 antibody is a protein c-factro that binds to phospholipids.. Beta-2 glycoprotein 1 antibody is an autoantibody that is associated with inappropriate blood clotting. This test detects and measures one or more classes (IgG, IgM, or IgA) of beta-2 glycoprotein 1 antibodies..