Predicting the likelihood of a persistent bile duct stone in patients with suspected choledocholithiasis: accuracy of existing guidelines and the impact of laboratory trends

Background: Existing guidelines aim to stratify the likelihood of choledocholithiasis to guide the use of ERCP versus a lower-risk diagnostic study such as EUS, MRCP, or intraoperative cholangiography. Objective: To assess the performance of existing guidelines in predicting choledocholithiasis and to determine whether trends in laboratory parameters improve diagnostic accuracy. Design: Retrospective cohort study. Setting: Tertiary-care hospital. Patients: Hospitalized patients presenting with suspected choledocholithiasis over a 6-year period. Interventions: Assessment of the American Society for Gastrointestinal Endoscopy (ASGE) guidelines, its component variables, and laboratory trends in predicting choledocholithiasis. Main Outcome Measurements: The presence of choledocholithiasis confirmed by EUS, MRCP, or ERCP. Results: A total of 179 (35.9%) of the 498 eligible patients met ASGE high-probability criteria for choledocholithiasis on initial presentation. Of those, 99 patients (56.3%) had a stone/sludge on subsequent confirmatory test. Of patients not meeting high-probability criteria on presentation, 111 (34.8%) had a stone/sludge. The overall accuracy of the guidelines in detecting choledocholithiasis was 62.1% (47.4% sensitivity, 73% specificity) based on data available at presentation. The accuracy was unchanged when incorporating the second set of liver chemistries obtained after admission (63.2%), suggesting that laboratory trends do not improve performance. Limitations: Retrospective study, inconsistent timing of the second set of biochemical markers. Conclusion: In our cohort of patients, existing choledocholithiasis guidelines lacked diagnostic accuracy, likely resulting in overuse of ERCP. Incorporation of laboratory trends did not improve performance. Additional research focused on risk stratification is necessary to meet the goal of eliminating unnecessary diagnostic ERCP.