Table 2.
Diagnostic performance of IS6110-qPCR among 4,047 respiratory specimens using cutoff Ct value at 24.14.
| IS6110 qPCR | Resolved performance (%) [95% CI] | |||||||
|---|---|---|---|---|---|---|---|---|
| AFB Smear | MTBC culture | Positive | Negative | Indeterminate | Sensitivity | Specificity | PPV | NPV |
| Positive (n = 97) | MTBC Positive (n = 93)a | 93 | 0 | 0 | 100 | 100 | 100 | 100 |
| MTBC Negative (n = 4) | 0 | 0 | 4 | |||||
| Negative (n = 3,950) | MTBC Positive (n = 370)a | 360 | 10 | 0 | 97.3 [95.1–98.7] | 99.2 [98.8–99.5] | 92.8 [89.9–94.9] | 99.7 [99.5–99.8] |
| MTBC Negative (n = 3,580) | 28 | 3,464 | 88 | |||||
| Clinical TB cases (n = 28)b | 28 | 0 | 0 | |||||
| Culture negative (n = 3,552) | 0 | 3,376 | 88c | |||||
a
MTB culture-positive specimens from original or subsequent specimens collected in consecutive days.
b
Clinical TB cases were defined as patients with abnormal chest radiographs compatible with pulmonary TB, or supported by other demographic features such as response to anti-TB treatment or patients with past TB history.
c
Indeterminate cases were yielded due to the absence of both IS6110 and internal control amplification.