Table 4.

Sensitivity, specificity, positive predictive values and negative predictive values for choledocolithiasis

Variable	Sensitivity	Specificity	PPV	NPV
Very strong predictors
Clinical ascending cholangitis	18.4	96.6	91.7	37.0
Common bile duct stone on US	55.9	89.9	91.7	50.3
Total bilirubin > 4 mg/dL	42.5	70.8	74.5	37.8
Strong predictors
Total bilirubin 1.8-4 mg/dL	61.1	66.6	75	51.2
Dilated common bile duct on US	83.8	49.4	76.9	60.3
Moderate predictors
Abnormal liver function test	89.9	21.3	69.7	51.3
Age > 55 yr	79.3	38.2	72.1	47.9
Gallstone pancreatitis	20.1	69.7	57.1	30.2
High risk group	86	56.2	79.8	66.7
Intermediate risk group	13.9	46	34,2	21

PPV: Positive predictive values; NPV: Negative predictive values; US: Ultrasonography.