Abstract: Objective To investigate the diagnostic value of γ-glutamyltransferase (GGT) for common bile duct stones.Methods The retrospective study was conducted. The clinical data of 248 patients who were treated by laparoscopic transcysitc common bile duct exploration (LTCBDE) from January 2016 to December 2016 were collected. To evaluate the sensitivity and specificity of preoperative GGT in the diagnosis of common bile duct stones, the golden standard was the common bile duct stones were found by choledochoscopy. The receiver operating characteristic (ROC) curve was done for indicators. Results The result of preoperative detection of GGT in the diagnosis of common bile duct stones was as follows:the area under the ROC curve was 0.729, the correspondent cut-off value of diagnostic accuracy, sensitivity, specificity, positive predictive rate, negative predictive rate and the accuracy were 93.5 U/L, 78.47%, 56.73%, 21.34%-24.25%,93.72-95.95% and 69.35%, respectively; After removal of silt stones:the area under the ROC curve was 0.779, the correspondent cut-off value of diagnostic accuracy, sensitivity, specificity, positive predictive rate, negative predictive rate and the accuracy were 93.5 U/L, 74.36%, 74.04%, 24.14%-33.58%, 94.24%-96.29% and 74.2% respectively.Conclusion GGT is a sensitive indicators for the diagnosis of common bile duct stones, but it is low specific. It should be highly suspected common bile duct stones when GGT>93.5U/L, magnetic resonance cholangiopancreatography (MRCP) or endoscopic retrograde cholangiopancreatography (ERCP) should be further examined. And it can be used as one of the indications of common bile duct exploration.

Key words: common bile duct stone, silt stones, diagnosis, γ-glutamyltransferase, laparoscopic common bile duct exploration