GPT and cholangiocarcinoma: Similarly, serum markers of liver injury and biliary obstruction (aspartate transaminase (AST), alanine transaminase (ALT), bilirubin, gamma-glutamyltransferase (GGT) and alkaline phosphatase (ALP)) and inflammation (CRP) were also elevated above the clinically established cut-off values (upper limit of normal), whereas the median leucocyte count of CCA patients was within the normal range (Table 2).