Serum Amylase Levels is a Predictor for Negative Endoscopic Retrograde Cholangiopancreatography for Suspected Common Bile Duct Stones

Negative endoscopic retrograde cholangiopancreatography (ERCP) for suspected common bile duct stones (CBDS) may be associated with significant morbidity and should be avoided. Between 2010 and 2018, 85 patients who have undergone negative ERCP for suspected CBDS were retrospectively evaluated and compared with 318 patients with positive findings. Predictors for negative ERCP were assessed. Patients with negative ERCP were younger; had increased levels of serum amylase, alanine transaminase, and lactate dehydrogenase; and increased hemoglobin. Even though preprocedure computed tomography (CT) or ultrasonography demonstrating CBDS were highly predictive of positive findings on ERCP, of the 212 patients with CBDS on computed tomography or ultrasonography, 17 (8%) eventually had a negative ERCP, suggesting spontaneous stone passage. An increased serum amylase level was the only predictor for negative ERCP in multivariate analysis, including in patients with preprocedure CBDS on imaging. The data suggest that assessing serum amylase may assist in avoiding unnecessary examinations.