Table 2 Risk factors and classification of risk for CBDS (modified from Maple et al. 2010)
| Very strong | Evidence of CBDS stone at the abdominal ultrasound |
| Ascending cholangitis | |
| Strong | Common bile duct diameter > 6 mm (with gallbladder in situ) |
| Total serum bilirubin level > 1.8 mg/dl | |
| Moderate | Abnormal liver biochemical test other than bilirubin |
| Age older than 55 years | |
| Clinical gallstone pancreatitis | |
| Risk class for choledocolithiasis | |
| High | Presence of any very strong |
| Low | No predictors present |
| Intermediate | All other patients |