TABLE 1.
Detection of M. tuberculosis complex infection by amplification assays, smear, and culture
| Method | No. of patients with positive result
|
Sensitivitya (%) | Specificitya (%) | Positive predictive valuea (%) | Negative predictive valuea (%) | ||
|---|---|---|---|---|---|---|---|
| Smear-positive culture-positive group (n = 66) | Smear-negative culture-positive group (n = 6) | Smear-negative culture-negative group (n = 158) | |||||
| COBAS AMPLICOR | 64 | 5 | 6 | 96.1 [95.8] | 100 [96.2] | 100 [92] | 98.1 [98.1] |
| LCx | 66 | 6 | 7b | 100 [100] | 99.3 [95.6] | 98.7 [91.1] | 100 [100] |
| MTD | 66 | 5 | 2 | 98.6 [98.6] | 99.4 [98.7] | 98.6 [97.3] | 99.4 [99.4] |
a
Unresolved data are shown in brackets.
b
After resolution, the results showed that LCx produced one false-positive result and MTD produced one false-positive result plus one false-negative result whereas COBAS AMPLICOR produced three false-negative results. No significant differences were obtained among the three methods for the smear-positive, culture-positive group (P = 0.133); smear-negative, culture-positive group (P = 0.570); and smear-negative, culture-negative group (P = 0.236).