Rat alpha Crosslaps / alpha CTx ELISA Kit (A78986) employs the competitive enzyme immunoassay technique for the quantitative measurement of rat alpha Crosslaps / alpha CTx in serum, plasma, tissue homogenates, and other biological fluids. The 96-well microtiter plate has been pre-coated with alpha Crosslaps / alpha CTx antigen. During the incubation, alpha Crosslaps / alpha CTx present in the samples or standards competes with the fixed amount of immobilized alpha Crosslaps / alpha CTx for binding sites on the Biotinylated Anti-alpha Crosslaps / alpha CTx Antibody. The more alpha Crosslaps / alpha CTx present in a sample or standard, the less Biotinylated Anti-alpha Crosslaps / alpha CTx Antibody that binds to the plate. Following incubation, unbound Biotinylated Anti-alpha Crosslaps / alpha CTx Antibody is removed by washing, and an HRP-Streptavidin conjugate is added to the wells and the microtiter plate is incubated. Following incubation and washing, TMB substrate solution is then used to visualize the HRP enzymatic reaction by catalysis to produce a blue-coloured product that changes to yellow after addition of acidic stop solution. The density of yellow is inversely proportional to the amount of alpha Crosslaps / alpha CTx present in each sample or standard. The concentration of alpha Crosslaps / alpha CTx can then be calculated by reading the O.D. absorbance at 450nm in a microplate reader and referring to the standard curve.