The kit specifically detects the endogenous secreted form of RAGE (i.e. esRAGE) in human plasma and serum samples. The esRAGE protein has been implicated in physiological changes associated with diabetes, Alzheimer''s, and vascular disease. The microplate is pre-coated with primary anti-esRAGE antibody. The secondary esRAGE antibody conjugated to HRP is added for detection. After incubation, 3,3'',5,5''-tetramethylbenzidine (TMB) and hydrogen peroxide are added as a colorimetric substrate for color development. Color is measured at 450 nm.