Abnormal common bile duct sonography. The best predictor of choledocholithiasis before laparoscopic cholecystectomy

We conducted a prospective study to determine the most reliable indicator of common bile duct stones before laparoscopic cholecystectomy. One hundred thirty-seven patients were referred for endoscopic retrograde cholangiography before laparoscopic cholecystectomy for suspected choledocholithiasis due to one or more of the following abnormalities: (a) altered liver function tests, (b) increased serum amylase levels, or (c) a dilated common bile duct (> 7 mm) with or without evidence of stones on sonography. Sensitivity, specificity, positive and negative predictive values, and the likelihood of the presence or absence of morbidity were calculated for 25 different variables. Common bile duct stones were detected in 63 (46%) patients. Abnormal result of sonography of the common bile duct was the best predictor of choledocholithiasis (p < 0.0001). Abnormalities of the combined liver function tests were statistically significant predictors only when combined with abnormal sonographic results. Improving liver function tests before endoscopy had a significant negative predictive value (p = 0.01). Stepwise logistic regression analysis showed that abnormal ultrasound and the presence of common bile duct stones on ultrasound were significant (p = 0.009 and p = 0.049, respectively). Abnormal result of sonography of the common bile duct is the best predictor of choledocholithiasis before laparoscopic cholecystectomy.