Device Description
INTENDED USE
Detection and semi-quantitation of anti-phosphatidylserine antibodies in individuals with systemic lupus erythematosus (SLE) and lupus-like disorders (anti-phospholipid syndrome). For In Vitro Diagnostic Use.
SUMMARY AND EXPLANATION OF THE ANTI-PHOSPHATIDYLSERINE TEST
High serum levels of anti-phospholipid antibodies are frequently detected in patients with autoimmune (i.e., SLE) and non-autoimmune diseases, as well as in apparently healthy individuals. These antibodies have been associated with an increased risk for recurrent arterial and venous thrombotic events, thrombocytopenia and fetal loss. Phosphatidylserine is a more physiologically relevant phospholipid due to its presence in cell membranes of endothelial cells and platelets.
PRINCIPLE OF THE TEST
The test is an indirect ELISA. Diluted serum/plasma samples, calibrator sera, and controls are incubated in phosphatidylserine coated microwells. β2-glycoprotein I is provided in the sample diluent. After the removal of unbound serum/plasma proteins by washing, antibodies specific for human IgG or IgM, labeled with horseradish peroxidase (HRP), are added forming complexes with the phosphatidylserine bound antibodies. Two enzyme-conjugated antibody solutions are provided, one specific for human IgG antibodies and one specific for human IgM antibodies. Following another washing 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-phosphatidylserine (aPS) antibodies. Results are obtained by reading the O.D. of each well in a spectrophotometer. Calibrator sera are provided for both IgG and IgM antibody concentrations expressed in GPS or MPS units. Control and patient results are determined from the calibration curve. Refer to Package Insert.