GPT and Biliary tract obstruction: Based on clinical serum data, we did not find any correlation between conventional biochemical indices of liver damage [aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP)] and bile duct obstruction [total and direct bilirubin, and gamma-glutamyl transpeptidase (g-GTP)] in the two BA groups (Table 2).