Used in biomedical research to quantify rat fibroblast growth factor 21 (FGF21) levels in biological samples such as serum, plasma, and cell culture supernatants. This ELISA kit enables researchers to study the role of FGF21 in metabolic regulation, including glucose homeostasis, insulin sensitivity, and lipid metabolism. It is commonly applied in studies related to diabetes, obesity, and non-alcoholic fatty liver disease (NAFLD) in rodent models. The assay provides a reliable and sensitive method for monitoring FGF21 expression changes in response to pharmacological treatments or genetic modifications.