IFN-γ is a cytokine that is primarily secreted by activated T cells and natural killer (NK) cells and plays an important role in activating innate/adaptive immunity. It also has been recognized as an indicator of T cell activation suggesting IFN-γ activation may be a prerequisite for CAR-T cell activity. The Colorimetric Human IFN-γ Detection Kit is designed for detecting and quantifying human interferon-γ in cell culture medium. Only a few simple steps on a microtiter plate are required for the assay. First, the capture antibody is coated on a 96-well plate. Next, samples containing IFN-γ are incubated on the coated plate followed by detecting the captured IFN-γ with the detection antibody. Finally, the plate is treated with streptavidin-HRP followed by addition of a colorimetric HRP substrate to produce color, which can then be measured using a UV/Vis spectrophotometer microplate reader.