Diagnostic value of liver function enzymes for choledocholithiasis

The study aimed to investigate the diagnostic value of liver function enzymes in patients with choledocholithiasis. The retrospective study included 120 choledocholithiasis patients (experimental group), 110 cholecysto-lithiasis patients (control group) and 60 healthy subjects (healthy group) from January 2013 to December 2014. Blood sample was extracted from each participant, and biochemical tests were performed for alanine aminotransferase (ALT), aspartate aminotransferase (AST), acid phosphatase (ACP), gamma-glutamyltranspeptidase (GGT), direct Bilirubin (DBIL) and indirect Bilirubin (IBIL). Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic value of each biochemical parameter for choledocholithiasis. A binary logistic regression model was established to assess the combined predictive power of two parameters. The experimental group had markedly increased serum levels of ALT, AST, ACP, GGT, DBIL and IBIL than the control group and the healthy group. ROC analysis revealed that of the 6 biochemical parameters, ALT, AST and GGT had area under the curve (AUC)>0.8. ALT, AST and GGT had low sensitivity (74.20%; 67.50%; 56.70%) and high specificity (80.00%; 93.60%; 92.70) at the optimal cutoff value (31.5 U/L; 39.0 U/L; 93.60%). Logistic regression analysis revealed that ALT and AST were independent predictors of common bile duct (CBD) stones. The combination of ALT and AST (AUC=0.85) did not markedly improved the AUC compared with ALT or AST singly. ALT, AST and GGT might be recommended as diagnostic biomarkers for CBD stone. The liver function test could only serve as a subsidiary diagnostic method.