Used primarily as a chromogenic substrate in enzyme-linked immunosorbent assays (ELISAs), it facilitates the detection of peroxidase activity by producing a blue color upon oxidation, which turns yellow when acid is added. This property makes it invaluable in diagnostic applications, particularly in medical and biological research for detecting antibodies, antigens, proteins, and other biomolecules. Additionally, it is employed in clinical diagnostics for identifying infectious diseases and monitoring immune responses. Its sensitivity and reliability in colorimetric assays contribute to its widespread use in various scientific and medical fields.