Tocilizumab is a recombinant, humanised, anti-human interleukin 6 (IL-6) receptor monoclonal antibody. Tocilizumab is mainly used for the treatment of rheumatoid arthritis (RA) and systemic juvenile idiopathic arthritis, a severe form of arthritis in children. BioSim™ Tocilizumab ELISA kit has been developed for specific quantification of Tocilizumab concentration in human serum or plasma with high sensitivity and reproducibility. Tocilizumab ELISA kit is based on the sandwich ELISA principle. Standards and samples (serum or plasma) are added in the microtiter plate coated with the reactant for Tocilizumab. After incubation, the wells are washed. The HRP conjugated probe is added and binds to Tocilizumab captured by the reactant on the surface of the wells. Following incubation wells are washed and the bound enzymatic activity is detected by addition of TMB chromogen substrate. Finally, the reaction is terminated with an acidic stop solution. The color developed is proportional to the amount of Tocilizumab in the sample or standard. Results of samples can be determined directly using the standard curve.