Description(s):
Serum Amyloid A (SAA) is an apolipoprotein which binds to lipids to form lipoprotein. This protein is secreted by the liver during the acute phase of inflammation. SAA levels increase within hours after an inflammatory stimulus and the level of response varies depending on the inflammatory stimuli. Because of this, SAA can be used a marker for inflammatory diseases such as amyloidosis, atherosclerosis, and rheumatoid arthritis.
Principle
The wells of the plate are coated with capture antibody specific to SAA. In this assay, the test sample initially reacts with the solid phase capture antibody, resulting in SAA being bound to the well. The wells are then washed to remove unbound proteins, and biotin-linked antibodies are added to bind to the immobilized SAA. After washing away the unbound antibodies, Streptavidin-HRP conjugate is added to form a complex with the antibody-bound SAA. After incubation, the wells are washed to remove unbound Streptavidin-HRP conjugate. TMB substrate is then added and forms a blue color when the HRP-linked antibodies are detected. The reaction is then terminated with Stop Solution, which changes the color from blue to yellow. The SAA concentration in each well is directly proportional to its color intensity and can be quantified by measuring its optical density at 450 nm (OD450) in a microplate reader.
