Principle of Assay
Universal 1,25-Dihydroxy Vitamin D3 ELISA Kit (A326312) is a 2 hour competitive Enzyme-Linked Immunosorbent Assay (cELISA) designed for the in vitro quantitative determination of universal 1,25-Dihydroxy Vitamin D3 in serum, plasma, cell culture supernatant, cell or tissue lysate, and other biological fluids. A 96-well microtiter plate has been pre-coated with 1,25-Dihydroxy Vitamin D3. During the assay, 1,25-Dihydroxy Vitamin D3 present in the standards or samples competes with immobilized 1,25-Dihydroxy Vitamin D3 for binding to an assay-specific antibody. Following incubation, unbound components are removed by washing and HRP-Streptavidin conjugate is added to the wells. After further incubation and washing, TMB substrate solution is added to visualize the HRP enzymatic reaction. This produces a blue-coloured product that changes to yellow following addition of acidic stop solution. The intensity of the colour is measured at 450 nm using a microplate reader. The concentration of 1,25-Dihydroxy Vitamin D3 in the samples is inversely proportional to the OD450 value and is determined by comparison with the standard curve.