Principle of Assay
Human Cytokeratin 18 ELISA Kit (High Sensitivity) (A334954) is a 4 hour sandwich Enzyme-Linked Immunosorbent Assay (sELISA) designed for the in vitro quantitative determination of human Cytokeratin 18 in serum, plasma, cell culture supernatant, cell or tissue lysate, and other biological fluids. A 96-well microtiter plate has been pre-coated with an antibody specific for Cytokeratin 18. Standards and samples are added to the wells, where Cytokeratin 18 binds to the immobilized capture antibody. Following incubation, unbound components are removed by washing and a biotinylated detection antibody specific for Cytokeratin 18 is added to the wells. The detection antibody binds the captured Cytokeratin 18 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 Cytokeratin 18 captured in each well. The concentration of Cytokeratin 18 is calculated by reading the absorbance at 450 nm and comparing the values with the standard curve.