4056 – Anti-Phosphatidylserin

Highlights

• Use of highly purified bovine phosphatidylserine and human β2-glycoprotein I as coating antigens
• Quantitative determination of IgG and/or IgM antibodies in human serum
• Supports the diagnosis of anti-phospholipid antibody syndrome (APAS) and related autoimmune disorders
• Differentiates autoimmune phospholipid antibodies from those seen in infectious diseases
• Detects disease-relevant autoantibodies recognizing phospholipid–protein complexes
• Detects tTG IgG autoantibodies, including in IgA-deficient celiac patients
• Manual test for professional in vitro diagnostic use
• CE marked

Intended Purpose

The Anti-Phosphatidylserine is a quantitative enzyme-linked immunosorbent assay (ELISA) for the determination of IgG and/or IgM antibodies against phosphatidyl-serine in human serum. The assay is intended as an aid in the diagnosis of anti-phospholipid antibody syndrome (APAS) in conjunction with clinical evaluation and other laboratory findings. The immunoassay is designed for manual professional in vitro diagnostic use.

Diagnostic Relevance

Anti-phospholipid antibody syndrome (APAS) is an autoimmune disorder characterized by clinical manifestations such as arterial or venous thrombosis, thrombocytopenia, and recurrent fetal loss. APAS may occur as a primary disorder or secondary to systemic lupus erythematosus (SLE). The presence of autoantibodies against negatively charged phospholipids, including phosphatidyl-serine, serves as a key biomarker for the disease and is critical in establishing diagnosis and monitoring disease progression.

Phospholipid autoantibodies in autoimmune patients often recognize phospholipids in association with plasma protein cofactors, such as β2-glycoprotein I (β2 GP-I). This 50 kDa serum protein modulates platelet aggregation and coagulation. The positively charged fifth domain of β2 GP-I binds negatively charged phosphatidyl-serine, triggering conformational changes in the protein and exposing new epitopes that autoimmune phospholipid autoantibodies specifically target. Detection of these autoantibodies allows for differentiation of APAS-related antibodies from transient phospholipid antibodies seen in certain infectious diseases.

The Anti-Phosphatidylserine assay offers a highly sensitive and specific method for the detection and quantification of anti-phosphatidyl-serine autoantibodies in human serum, supporting clinicians in risk assessment, disease monitoring, and patient management. This assay is particularly valuable when used in conjunction with other serological tests, clinical evaluations, and imaging studies to provide a comprehensive assessment of autoimmune thrombotic risk.