Device Description
INTENDED USE
For the detection and semi-quantitation of IgG anti-β2GPl antibodies in individuals with systemic lupus
erythematosus (SLE) and lupus-like disorders (anti-phospholipid syndrome). For In Vitro Use Only.
SUMMARY OF THE TEST
Anti-phospholipid antibodies are a heterogeneous group of immunoglobulins that bind to several anionic phospholipids, including cardiolipin and phosphatidylserine. High serum levels of anti-phospholipid antibodies are frequently detected in patients with autoimmune (e.g., SLE) and non-autoimmune diseases, as well as in apparently healthy individuals. Patients with positive reactions to both anti-phospholipid and anti-β2GPl assays were more likely to have clinical complications than those positive for only one. Higher prevalence and mean serum levels of IgG anti-β2GPl antibodies have been reported in autoimmune patients. In addition, anti-β2GPl antibodies in SLE patients correlated with clinical manifestations of anti-phospholipid syndrome.
PRINCIPLE OF THE TEST
The test is an indirect ELISA. Diluted serum/plasma samples, calibrator sera, and controls are incubated in microwells coated with purified human β2GPl. After the removal of unbound serum or plasma proteins by washing, antibodies specific for human IgG, labeled with horseradish peroxidase (HRP), are added forming complexes with the β2GPl bound antibodies. Following another wash step, the bound enzyme-antibody conjugate is assayed by the addition of a single solution containing tetramethylbenzidine (TMB) and hydrogen peroxide (H2O2) as the chromogenic substrate. Color develops in the wells at an intensity proportional to the serum concentration of anti-β2GPl antibodies. Results are obtained by reading the O.D. of each well in a spectrophotometer. Calibrator sera are provided, with the IgG anti-β2GPl antibody concentrations expressed in G units. Controls and patient results are determined from the calibration curve. Refer to Product Package Insert.