This kit was based on Competitive-ELISA detection method. The microtiter plate provided in this kit has been pre-coated with Indoxyl Sulphate. During the reaction, Indoxyl Sulphate in the sample or standard competes with a fixed amount of Indoxyl Sulphate on the solid phase supporter for sites on the Biotinylated Detection Antibody specific to Indoxyl Sulphate. Excess conjugate and unbound sample or standard are washed from the plate, and HRP-Streptavidin (SABC) is added to each microplate well