The ROS-Glo H2O2 Assay is a homogeneous, fast and sensitive bioluminescent assay that measures the level of hydrogen peroxide (H2O2), a reactive oxygen species (ROS), directly in cell culture or in defined enzyme reactions. A derivatized luciferin substrate is incubated with sample and reacts directly with H2O2 to generate a luciferin precursor. Addition of ROS-Glo Detection Solution converts the precursor to luciferin and provides Ultra-Glo Recombinant Luciferase to produce light signal that is proportional to the level of H2O2 present in the sample.