Background: To determine the predictive factors of synchronous common bile duct (CBD) stones, data from 878 consecutive patients who underwent cholecystectomy in a university clinic from June 1991 to June 1996 were retrospectively analyzed. Methods: Based on clinical, biochemical, and ultrasonographic criteria, 194 patients were selected for ERCP, 180 preoperative and 14 postoperative. Results: Cannulation of CBD was successful in 192 (99%) patients. Stones were identified in 62 (32%) patients and sphincterotomy was performed in 56 (90%). Duct clearance was achieved in 43 (77%) cases. There was a high predictive value for the presence of CBD stones in patients with cholangitis, present jaundice, and dilated CBD with evidence of stones on ultrasound (75%, 72%, and 67% respectively). A dilated CBD without stone on ultrasound and elevated liver enzymes had less than 40% positive predictive value. History of previous jaundice, pancreatitis, previously raised liver enzymes, and present pancreatitis was predictive in less than 20% of the cases. Univariate analyses revealed that clinical findings of cholangitis and obstructive jaundice, elevated liver enzymes (previous and present), and ultrasonographic findings of stones in a dilated CBD were significant positive predictors. Subanalysis of each elevated liver enzyme revealed that alanine transaminase, aspartate transaminase, alkaline phosphatase, and gamma glutamyl transpeptidase were significant predictors. Both elevated conjugated and total bilirubins were also significant predictors for CBD stones. Conclusion: Multivariate logistic regression analysis on these significant predictors showed that cholangitis (odds ratio [OR]: 10.5), dilated CBD with evidence of stones on ultrasound (OR: 7.4), elevated aspartate transaminase (OR: 2.9), and conjugated bilirubin (OR: 5.3) were jointly significant. The likelihood of having stones in the duct without any of these predictors was 7%, but 99% when all the predictors were positive. more...