TABLE 5.
Diagnostic performance of the phenotypic DST, MTBDRplus, and VerePLEX Biosystem for detecting M. tuberculosis in clinical isolates and specimensa
| Parameter | Value (95% CI) for clinical isolates (n = 91) |
Value (95% CI) for clinical specimens (n = 196)b by MTBDRplus/seq/Xpert MTB-RIF | No. of indeterminate results/total (%) | |
|---|---|---|---|---|
| MTBDRplus/seq | DST | |||
| Sensitivity (%) | 100.00 (95.95, 100.00) | 100.00 (95.95, 100.00) | 100.00 (95.31, 100.00) | 2/196 (1.02) |
| Specificity (%) | Undefined | Undefined | 100.00 (96.79, 100.00) | |
| PPV (%) | 100.00 (95.95, 100.00) | 100.00 (95.95, 100.00) | 100.00 (95.31, 100.00) | |
| NPV (%) | Undefined | Undefined | 100.00 (96.79, 100.00) | |
| Negative likelihood ratio | Undefined | Undefined | 0.00 | |
| Diagnostic accuracy (%) | Undefined | Undefined | 100.00 (98.06, 100.00) | |
The diagnostic performance of the MTBDRplus/seq assays, phenotypic drug susceptibility testing (DST), and MTBDRplus/seq/Xpert MTB-RIF assays for detecting M. tuberculosis are shown. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), and diagnostic accuracy were calculated according to the Wilson score (www.OpenEpi.com). The positive and negative likelihood ratios were also calculated. The lower and upper limits of the 95% confidence interval (95% CI) are shown in parentheses. The effective number of samples considered for the analysis is reported for each target. The positive likelihood ratio cannot be computed, since specificity is always 100%.
There were a total of 80 M. tuberculosis-positive smear-positive clinical specimens and a total of 116 M. tuberculosis-negative clinical specimens.