Background: To provide optimal selection of patients for preoperative endoscopic retrograde cholangiopancreatography or intraoperative cholangiography, we evaluated simple, noninvasive biochemical parameters as screening tests to predict the absence of common bile duct stones prior to laparoscopic cholecystectomy.
Methods: A total of 1002 patients underwent laparoscopic cholecystectomy. Five biochemical parameters were measured preoperatively: gamma glutamyl transferase (GGT), alkaline phosphatase, total bilirubin, alanine aminotransferase, and aspartate aminotransferase. Conventional diagnostic tests, including ultrasound imaging, computed tomography, magnetic resonance imaging, common bile duct diameter, endoscopic retrograde cholangiopancreatography, and serum amylase were performed. Along with the five biochemical tests above, these diagnostic tests were scrutinized and compared as potential predictors for common bile duct stones.
Results: Eighty-eight (8.8%) patients with gallstone disease who underwent laparoscopic cholecystectomy had concurrent common bile duct stones. Among all diagnostic tests, endoscopic retrograde cholangiopancreatography had the highest sensitivity (96.0%), specificity (99.1%), probability ratio (107.3), accuracy (98.0%), and positive predictive value (98.8%) in detecting common bile duct stones. At least one abnormal elevation among the five biochemical parameters had the highest sensitivity (87.5%). Total bilirubin had the highest specificity (87.5%), highest probability ratio (3.9), highest accuracy (84.1%), and highest positive predictive value (27.4%). All five biochemical predictors had high negative predictive values; gamma glutamyl transferase was highest (97.9%), while the lowest was total bilirubin (94.7%). Multivariate analysis showed only gamma glutamyl transferase, alkaline phosphatase, and total bilirubin to be independent predictors; gamma glutamyl transferase appeared to be the most powerful predictor (odds ratio 3.20).
Conclusion: Biochemical tests, especially gamma glutamyl transferase with 97.9% negative predictive value, are ideal noninvasive predictors for the absence of common bile duct stones in patients undergoing laparoscopic cholecystectomy. We suggest that unnecessary, costly, or risky procedures such as endoscopic retrograde cholangiopancreatography can be omitted prior to laparoscopic cholecystectomy in patients without abnormal elevation of these biochemical values.