FGF21 and Hepatic steatosis: A GGT cut-off of 28 U/L, citrulline level of 18.5 μmol/L, and liver stiffness of 5.7 kPa (measured by vibration-controlled transient elastography) had sensitivities for detecting active IFALD of 86%, 83%, and 83%, and specificities of 85%, 71%, and 79%, respectively, with combinations providing higher accuracy.7Another biomarker being investigated as a surrogate for liver steatosis is fibroblast growth factor (FGF) 21 (FGF21), which is produced by the liver and regulates glucose and lipid metabolism.