Table 2. Performance of Ziehl-Neelsen staining, culture, and polymerase chain reaction dot-blot assays, according to the history of anti-tuberculosis treatment, among human immunodeficiency virus-seropositive individuals.
| Laboratory results and performance of methods | ||||||
|---|---|---|---|---|---|---|
| All groups N=74 |
Non-treated TB group N=47 |
Past-TB group N=27 |
||||
| TB | Non-TB | TB | Non-TB | TB | Non-TB | |
| N=40 | N=34 | N=32 | N=15 | N=8 | N=19 | |
| ZN | ||||||
| Positive | 17 | 0 | 14 | 0 | 3 | 0 |
| Negative | 23 | 34 | 18 | 15 | 5 | 19 |
| SE | SP | SE | SP | SE | SP | |
| 43% | 100% | 43% | 100% | 37% | 100% | |
| LR+ | LR− | LR+ | LR− | LR+ | LR− | |
| 43 | 0.58 | 43 | 0.57 | 37 | 0.62 | |
| Culture | ||||||
| Positive | 32 | 0 | 27 | 0 | 5 | 0 |
| Negative | 8 | 34 | 5 | 15 | 3 | 19 |
| SE | SP | SE | SP | SE | SP | |
| 80% | 100% | 84% | 100% | 62% | 100% | |
| LR+ | LR− | LR+ | LR− | LR+ | LR− | |
| 80 | 0.20 | 84 | 0.16 | 62 | 0.38 | |
| PCR dot-blot | ||||||
| Positive | 29 | 5 | 23 | 2 | 6 | 3 |
| Negative | 11 | 29 | 9 | 13 | 2 | 16 |
| SE | SP | SE | SP | SE | SP | |
| 72% | 85% | 72% | 87% | 75% | 84% | |
| LR+ | LR− | LR+ | LR− | LR+ | LR− | |
| 4.8 | 0.33 | 5.6 | 0.32 | 4.7 | 0.29 | |
| Performance of methods used in parallel | ||||||
|---|---|---|---|---|---|---|
| ZN in parallel with | SE | SP | SE | SP | SE | SP |
| Culture | 89% | 100% | 91% | 100% | 78% | 100% |
| ZN in parallel with | SE | SP | SE | SP | SE | SP |
| PCR dot -blot | 84% | 85% | 84% | 87% | 86% | 84% |
SE, sensitivity; LR+, positive likelihood ratio; SP, specificity; LR−, negative likelihood ratio.