Table 4. ROC curve analysis results.

	Sensitivity	Specificity	PPV	NPV	Area under the ROC curve				P	Cutoff
					Area	Standard error	Confidence interval
Total score	90.00	95.83	84.91	97.35	0.967	0.011	0.946	0.988	< 0.001	4.5
Question 1	90.00	72.40	45.92	96.53	0.812	0.023	0.768	0.856	< 0.001	1.0
Question 2	71.00	52.86	28.17	87.50	0.619	0.031	0.559	0.679	< 0.001	0.5
Question 3	91.00	60.16	37.30	96.25	0.825	0.023	0.779	0.870	< 0.001	0.5
Question 4	27.00	83.85	30.34	81.52	0.554	0.033	0.489	0.620	0.094	0.5
Question 5	70.00	93.75	74.47	92.31	0.819	0.028	0.763	0.875	< 0.001	1.0
Total score (without Q4)	97.00	87.50	66.90	99.12	0.964	0.012	0.941	0.987	< 0.001	3.5

ROC = receiver operating characteristic; PPV = positive predictive value; NPV = negative predictive value.