Used for the quantitative measurement of histidine decarboxylase (HD) activity in rat biological samples such as tissue homogenates, cell lysates, and serum. This ELISA kit enables researchers to assess HD enzyme levels, which is critical in studies related to histamine production, allergic responses, gastric acid secretion, and neurochemical processes in rat models. It is widely applied in pharmaceutical research, immunology, and neuroscience to evaluate changes in HD activity under experimental conditions or disease states. The assay provides high sensitivity and specificity, allowing for reliable detection of HD activity differences in preclinical studies.