TABLE 3.
Performance of Genotype MTBDRsl v2.0 and the first version of the MTBDRsl assay compared to phenotypic DST on 127 clinical isolatesa
| Parameter | Performance of MTBDRsl v2.0 [and MTBDRsl first version] compared to phenotypic DST |
pre-XDR |
XDR |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Fluoroquinolone |
Kanamycin |
Amikacin |
Capreomycin |
|||||||||
| Value | (95% CI) | Value | (95% CI) | Value | (95% CI) | Value | (95% CI) | Value | (95% CI) | Value | (95% CI) | |
| % sensitivity | 94.8[89.6 | (87.4, 98.0)(80.8, 94.6)] | 90.5[59.5 | (81.7, 95.3)(48.1, 69.9)] | 91.3[91.3 | (79.7, 96.6)(79.7, 96.6)] | 83.0[83.0 | (70.8, 90.8)(70.8, 90.8)] | 83.3[75.0 | (70.4, 91.3)(61.2, 85.1)] | 83.0[49.1 | (70.8, 90.8)(36.1, 62.1)] |
| % specificity | 98[98 | (89.5, 99.7)(89.5, 99.7)] | 94.3[100 | (84.6, 98.1)(93.2, 100)] | 100[100 | (95.5, 100)(95.5, 100)] | 100[100 | (95.1, 100)(95.1, 100)] | 88.6[67.1 | (70.7, 93.9)(56.1, 76.5)] | 100[100 | (95.1, 100)(95.1, 100)] |
| PPV (%) | 98.7[98.6 | (92.7, 99.8)(92.3, 99.8)] | 95.7[100 | (88.1, 98.5)(92.0, 100)] | 100[100 | (91.6, 100)(91.6, 100)] | 100[100 | (92.0, 100)(92.0, 100)] | 81.6[58.1 | (68.6, 90.0)(45.7, 69.5)] | 100[100 | (92.0, 100)(87.1, 100)] |
| NPV (%) | 92.4[86.0 | (82.1, 97.0)(74.7, 92.7)] | 87.7[63.9 | (76.75, 93.9)(53.1, 73.4)] | 95.3[95.3 | (88.5, 98.2)(88.5, 98.2)] | 89.2[89.2 | (80.7, 94.2)(80.7, 94.2)] | 89.7[81.5 | (81.0, 94.7)(70.4, 89.1)] | 89.2[73.3 | (80.7, 94.2)(63.9, 80.9)] |
| Positive likelihood ratio | 47.4[44.8 | (6.7, 337)(6.3, 319.1)] | 16.0[UD | (8.3, 30.8)UD] | UD[UD | UDUD] | UD[UD | UDUD] | 7.3[2.3 | (5.8 9.2)(2.1, 2.5)] | UD[UD | UDUD] |
| Negative likelihood ratio | 0.05[0.11 | (0.03, 0.09)(0.08, 0.14)] | 0.10[0.41 | (0.08, 0.13)(0.38, 0.43)] | 0.09[0.09 | (0.05, 0.14)(0.05, 0.14)] | 0.17[0.17 | (0.14, 0.21)(0.14, 0.21)] | 0.19[0.37 | (0.14, 0.24)(0.31, 0.45)] | 0.17[0.51 | (0.14, 0.21)(0.47, 0.55)] |
| Diagnostic accuracy (%) | 96.1[92.9 | (91.1, 98.3)(87.1, 96.2)] | 92.1[76.4 | (86.1, 95.7)(68.2, 82.9)] | 96.8[96.8 | (92.2, 98.8)(92.2, 98.8)] | 92.9[92.9 | (87.1, 96.2)(87.1, 96,2)] | 86.6[70.1 | (79.6, 91.5)(61.6, 77.4)] | 92.9[78.7 | (87.1, 96.2)(70.8, 85.0)] |
a
CI, confidence interval; DST, drug susceptibility testing; PPV, positive predictive value; NPV, negative predictive value; UD, undefined.