Grande et al developed a score for identifying a patient at risk for a common bile duct stone using risk factors available prior to laparoscopic cholecystectomy. This can help to reduce the number of unnecessary explorations of the common bile duct. The authors are from the University of Rome Tor Vergata and Vanderbilt University.



(1) diameter of the common bile duct on ultrasonography in mm

(2) serum alkaline phosphatase in IU/L

(3) serum total bilirubin in mg/dL

(4) number of gallstones within the gallbladder


References ranges for the chemistry tests:

(1) alkaline phosphatase: 98 to 279 IU/L

(2) total bilirubin: < 1.2 mg/dL


X =

= (0.22 * (diameter of common bile duct in mm)) + (0.232 * (serum total bilirubin)) + (0.002 * (serum alkaline phosphatase)) + (0.485 * (number of gallstones)) - 4.167



• The number of stones of varying sizes might improve the score. A small stone is more likely to get into the common bile duct, while a larger stone might be less likely to pass.

• The analytic methods for alkaline phosphatase and total bilirubin were not reported.

• Transporting the score to a new location would require adjusting the local reference ranges for alkaline phosphatase and total bilirubin to the ranges used in the study.



• A score < 0 indicates a low risk for a stone in the common bile duct.

• A score > 0 indicates a high risk of one or more stones in the common bile duct.

• Intraoperative cholangiography was reserved for a patient at high risk for a stone.

• It is assumed that an intraoperative cholangiogram would also be done if there was evidence of a stone in the common bile duct seen on ultrasonography.


Performance in the author's study:

• The sensitivity was 93% and the specificity was 99.3%.


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