Table 5.
Sensitivity and specificity of conventional methods, nMPCR assay and CRS with respect to different specimens
| Different testes | Test results | TB group | Control (n = 150) | Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) | CI |
|---|---|---|---|---|---|---|---|---|
| Pulmonary TB (n = 535) | ||||||||
| AFB smear | Positive Negative |
287 128 |
0 120 |
69.2 | 100 | 100 | 48.4 | 64.5 % – 73.6 % |
| Culture | Positive Negative |
329 86 |
0 120 |
79.3 | 100 | 100 | 58.2 | 75.0 % – 83.1 % |
| Single step mPCR | Positive Negative |
345 70 |
0 120 |
83.1 | 100 | 100 | 63.2 | 79.2 % – 86.6 % |
| nMPCR | Positive Negative |
403 12 |
0 120 |
97.1 | 100 | 100 | 90.9 | 95.0 % – 98.5 % |
| CRS | Positive Negative |
415 0 |
0 120 |
100 | 100 | 100 | 100 | 99.1 % –100.0 % |
| Extra-pulmonary TB (n = 65) | ||||||||
| Z-N smear | Positive Negative |
15 20 |
- 30 |
42.9 | 100 | 100 | 60.0 | 26.3 % – 60.6 % |
| Culture | Positive Negative |
19 16 |
- 30 |
54.3 | 100 | 100 | 65.2 | 36.6 % – 71.2 % |
| Single step mPCR | Positive Negative |
20 15 |
- 30 |
57.1 | 100 | 100 | 66.7 | 39.3 % – 73.7 % |
| nMPCR | Positive Negative |
32 3 |
2 28 |
91.4 | 93.3 | 94.1 | 90.3 | 76.9 % – 98.2 % |
| CRS | Positive Negative |
35 0 |
0 30 |
100 | 100 | 100 | 100 | 90.0 % to 100.0 % |
PPV positive predictive value, NPV negative predictive value, TB group TB suspected patients, mPCR multiplex PCR, nMPCR nested multiplex PCR, CRS composite reference standard