Used to measure levels of Fibroblast Growth Factor-19 (FGF-19) in human biological samples such as serum, plasma, or cell culture supernatants. This assay is commonly applied in metabolic disease research, particularly in studies related to bile acid regulation, glucose metabolism, and liver function. It supports investigation into conditions like non-alcoholic fatty liver disease (NAFLD), type 2 diabetes, and cholestatic liver diseases. The kit enables researchers to quantify FGF-19 with high sensitivity and specificity, making it valuable in clinical research and drug development settings where monitoring FGF-19 dynamics is essential.