Used primarily as a chromogenic substrate in ELISA (Enzyme-Linked Immunosorbent Assay) tests, it helps in detecting the presence of antibodies or antigens. When oxidized by horseradish peroxidase (HRP), it produces a blue color, which can be measured spectrophotometrically to quantify the target molecule. It is also employed in immunohistochemistry for visualizing enzyme activity in tissue samples. Additionally, it serves as a reagent in various biochemical assays for studying enzymatic reactions and oxidative processes. Its sensitivity and stability make it a preferred choice in diagnostic and research applications.