2.2. Laboratory Methods
BLOOD
Blood samples from the NASHFit trial were collected after an overnight fast and, after processing, immediately stored at −80 °C. FGF21 levels were assessed using a Human FGF21 Quantikine enzyme-linked immunoassay (ELISA) kit (catalog number DF2100) from R&D Systems (Minneapolis, MN, USA) following the manufacturer’s instruction.