4050 – Anti-Phospholipid screen

Intended Purpose

The Anti-Phospholipid screen is a quantitative immunoassay for the determination of IgG and / or IgM antibodies against phospholipides (cardiolipin, phosphatidyl-serine, -inositol, -ethanolamine, phosphatidic acid and ß2-glycoprotein I) in human serum. The Anti-Phospholipid screen is intended as an aid in the diagnosis of anti-phospholipid antibody syndrome (APAS) in conjunction with other clinical and laboratory findings. The immunoassay is designed for manual professional in vitro diagnostic use.

Diagnostic Relevance

APAS, an autoimmune disorder evident by clinical symptoms such as thrombocytopenia, arterial (venous) thrombosis, and recurrent foetal loss, as well as systemic lupus erythematosus (SLE) are characterized by the presence of autoantibodies reactive to negatively charged phospholipids. The detection of such autoantibodies is well established and plays an essential role in the diagnostics of systemic autoimmune diseases.

In autoimmune patients, phospholipid antibodies seem to recognize phospholipids associated with plasma protein cofactors, e.g. ß₂ glycoprotein-I (ß₂ GP-I), a serum protein with a molecular weight of ca. 50 kDa, that affects platelet aggregation and coagulation. Negatively charged phospholipids such as Cardiolipin interact with the positively charged fifth domain of ß₂ GP-I, an interaction that leads to conformational changes of the protein and the creation of new epitopes recognized by autoimmune phospholipid autoantibodies.