Table 2.

Sensitivity, specificity and Youden index for different cut-off points

Cut point	Sensitivity	1—Specificity	Youden Index
10	1	1	0.000
11.5	1	0.988	0.012
12.5	1	0.95	0.050
13.5	1	0.888	0.112
14.5	1	0.838	0.162
15.5	0.975	0.713	0.262
16.5	0.975	0.675	0.300
17.5	0.975	0.575	0.400
18.5	0.975	0.525	0.450
19.5	0.95	0.475	0.475
20.5	0.95	0.425	0.525
21.5	0.925	0.325	0.600
22.5	0.875	0.225	0.650
23.5	0.825	0.188	0.637
24.5	0.775	0.162	0.613
25.5	0.7	0.125	0.575
26.5	0.675	0.05	0.625
27.5	0.6	0.037	0.563
28.5	0.55	0.037	0.513
29.5	0.55	0.025	0.525
30.5	0.425	0.025	0.400
31.5	0.25	0.025	0.225
32.5	0.225	0.012	0.213
33.5	0.125	0.012	0.113
34.5	0.075	0	0.075
36	0.05	0	0.050
37.5	0.025	0	0.025
39	0	0	0.000