Inclusion Criteria:  Patients with suspected choledocholithiasis, regardless of probability age 18 years old or older able to give informed consent to involvement (in the prospective validation phase).  Exclusion Criteria:  Unable or unwilling to provide informed consent; age < 18 years; suspected or proven cholangitis; previous ERCP with sphincterotomy; prior diagnosis or management of choledocholithiasis; outpatient status; out-of-province status (prohibiting full medical record access).