Table 2.
Serum IgG responses to seven mycobacterial antigens.
| Group | Optical density at 450 nm (mean ± SD) and positive rate (%) | ||||||
|---|---|---|---|---|---|---|---|
| ESAT-6 | CFP-10 | MDP1 | Ag85A | Acr | HBHA | HrpA | |
| Cut-off values | 0.067 | 0.077 | 0.118 | 0.037 | 0.129 | 0.140 | 0.072 |
| Negative control | 0.068 ± 0.155 36.4% |
0.084 ± 0.160 41.9% |
0.103 ± 0.108 36.5% |
0.037 ± 0.074 44.6% |
0.143 ± 0.213 32.4% |
0.091 ± 0.157 23.0% |
0.050 ± 0.210 16.2% |
| Active disease | 0.248 ± 0.590a
55.7% |
0.252 ± 0.508a
58.0% |
0.157 ± 0.240 48.9% |
0.068 ± 0.246 51.1% |
0.487 ± 0.714b
76.1% |
0.351 ± 0.502b
59.3% |
0.256 ± 0.276b
77.3% |
| Past disease | 0.068 ± 0.129c
39.3% |
0.230 ± 0.345 64.3% |
0.207 ± 0.259d
54.8% |
0.080 ± 0.136 56.0% |
0.277 ± 0.381c
66.7% |
0.300 ± 0.436d
58.3% |
0.290 ± 0.264e
79.8% |
| Latent TB infection | 0.079 ± 0.100 41.2% |
0.195 ± 0.190 76.5% |
0.257 ± 0.320 52.9% |
0.040 ± 0.115 41.2% |
0.210 ± 0.292 64.7% |
0.277 ± 0.334 64.7% |
0.325 ± 0.368f
82.4% |
|
| |||||||
| AUROC | 0.63 | 0.59 | 0.52 | 0.51 | 0.74 | 0.74 | 0.82 |
a P < 0.05 (active versus control), b P < 0.01 (active versus control), c P < 0.05 (active versus past), d P < 0.05 (past versus control), e P < 0.01 (past versus control), f P < 0.01 (latent versus control).
Optimal cut-off values were chosen when the Youden's index (sensitivity and specificity − 1) was maximal.
AUROC: areas under the receiver operating characteristic curve.