Principle of Assay
Human SFRP4 ELISA Kit (A77315) is a 4 hour sandwich Enzyme-Linked Immunosorbent Assay (sELISA) designed for the in vitro quantitative determination of human SFRP4 in serum, plasma, tissue homogenates, and other biological fluids. A 96-well microtiter plate has been pre-coated with an antibody specific for SFRP4. Standards and samples are added to the wells, where SFRP4 binds to the immobilized capture antibody. Following incubation, unbound components are removed by washing and a biotinylated detection antibody specific for SFRP4 is added to the wells. The detection antibody binds the captured SFRP4 to form an antibody-antigen-antibody sandwich complex. After further incubation and washing, HRP-Streptavidin conjugate is added to the wells. TMB substrate solution is then 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 yellow colour is directly proportional to the amount of SFRP4 captured in each well. The concentration of SFRP4 is calculated by reading the absorbance at 450 nm and comparing the values with the standard curve.