TABLE 2.
Performance evaluation of GeneChip for rifampin and isoniazid resistance in tuberculosis cases with different treatment historiesa
| GeneChip | Conventional drug susceptibility testingc |
Sensitivity (%) | Specificity (%) | AR | PPV (%) | NPV (%) | Kappa | PLR (%) | NLR (%) | ||
|---|---|---|---|---|---|---|---|---|---|---|---|
| No. susceptible (%) | No. resistant (%) | Total no. | |||||||||
| New cases | |||||||||||
| Rifampin | 94.8 | 97.8b | 97.6b | 68.8 | 99.7b | 0.78 | 42.30 | 0.05 | |||
| Susceptible | 1,090 (97.8) | 3 (5.2) | 1,093 | ||||||||
| Resistant | 25 (2.2) | 55 (94.8) | 80 | ||||||||
| Total | 1,115 | 58 | |||||||||
| Isoniazid | 70.9 | 97.3 | 94.8b | 72.9 | 97.0 | 0.69 | 26.0 | 0.30 | |||
| Susceptible | 1,034 (97.3) | 32 (29.1) | 1,066 | ||||||||
| Resistant | 29 (2.7) | 78 (70.9) | 107 | ||||||||
| Total | 1,063 | 110 | |||||||||
| Previously treated cases | |||||||||||
| Rifampin | 94.6 | 91.3 | 92.1 | 77.6 | 98.1 | 0.8 | 10.8 | 0.06 | |||
| Susceptible | 157 (91.3) | 3 (5.5) | 160 | ||||||||
| Resistant | 15 (8.7) | 52 (94.5) | 67 | ||||||||
| Total | 172 | 55 | |||||||||
| Isoniazid | 69.7 | 95.4 | 86.8 | 88.3b | 86.2 | 0.69 | 15.0 | 0.32 | |||
| Susceptible | 144 (95.4) | 23 (30.3) | 167 | ||||||||
| Resistant | 7 (4.6) | 53 (69.7) | 60 | ||||||||
| Total | 151 | 76 | |||||||||
a
Abbreviations: PPV, positive predictive value; NPV, negative predictive value; AR, agreement rate; PLR, positive likelihood ratio; NLR, negative likelihood ratio.
b
Statistically significantly different from the opposing type of case with the same drug (P < 0.05).
c
Culture was used as the gold standard.