Transaminases is not a sensitive test for NAFLD/NASH, as there is poor correlation of ALT with histology. ALT also typically decreases with advanced fibrosis. GGT on the other hand, has been shown to be associated with fatty liver.

Thank you, Dr. Wong, for the informative answer

GGT is more sensitive and specific than ALT, while AST elevations also reflect muscle injury, so is nonspecific. ALP reflects liver and bone disease and is least sensitive for fatty liver documentation.