Antiphospholipid antibodies, Ig G

IgG-class antiphospholipid autoantibodies are produced against antigens of structural components of cell membranes – phospholipids. The main role of antiphospholipid antibodies is related to disturbances in blood clotting. APS affects the membranes of endothelial cells (the inner lining of blood vessels), thereby activating coagulation processes and leading to thrombus formation. This test is used in the diagnosis of antiphospholipid syndrome, which manifests in women as recurrent pregnancy loss. In men, antiphospholipid syndrome can cause deep vein thrombosis, and is often associated with complications of ischemic heart disease and other manifestations of atherosclerosis.

The antiphospholipid antibody test is needed to detect specific phospholipid-associated proteins that the body produces against itself as part of an autoimmune response to phospholipids. Phospholipids are an essential component of the body’s cells, forming part of cell membranes and platelets. Essentially, they are fat molecules that play a key role in blood clotting, although the exact mechanism of their influence is still unclear. Antiphospholipid antibodies increase the risk of clotting disorders and thrombosis in arteries and veins, potentially leading to strokes and heart attacks.

Antiphospholipid antibodies are also associated with thrombocytopenia (low platelet count), the risk of recurrent miscarriages (especially in the second and third trimesters), premature births, and pregnancy-related complications such as preeclampsia.

The presence of these antibodies is part of a symptom complex called antiphospholipid syndrome (APS), or Hughes–Stovin syndrome. It also includes thrombosis, obstetric complications (miscarriages, recurrent pregnancy loss), and thrombocytopenia. APS can be associated with other autoimmune diseases, particularly systemic lupus erythematosus (secondary APS), or may develop without concomitant pathologies (primary APS).

However, antiphospholipid antibodies often appear in other autoimmune disorders, such as systemic lupus erythematosus; they may also be observed in HIV infection, certain cancers, or during medication intake (e.g., phenothiazines or novocainamide). Therefore, testing for anticardiolipin antibodies is considered an additional test and alone is not a definitive criterion for APS – APS diagnosis must be comprehensive and include multiple clinical indicators.

Preparation:

• Blood sample should be taken on an empty stomach. The last meal should be at least 8 hours before visiting the test center.
• Avoid smoking for at least one hour before the test.

Recommendations:

• Avoid physical exertion before the test. Take a 10–20 minute rest before sample collection to relax.
• ​​​​​​​Postpone testing immediately after paraclinical procedures (X-ray, CT, MRI) or physiotherapy, as they may affect test results.