Table 6. Sensitivity and specificity of different phenotypic methods in relation to PCR among carbapenem-resistant isolates from VAP patients.
| PCR | Sensitivity | Specificity | PPV | NPV | Diag. accuracy | ||||
|---|---|---|---|---|---|---|---|---|---|
| Positive | Negative | ||||||||
| No. | % | No. | % | ||||||
| MHT +ve | 40 | 76.9 | 26 | 55.3 | 76.9 | 44.7 | 60.6 | 63.6 | 61.6 |
| MHT–ve | 12 | 23.1 | 21 | 44.7 | |||||
| eCIM +ve | 50 | 96.2 | 8 | 17.0 | 96.2 | 83.0 | 86.2 | 95.1 | 89.9 |
| eCIM -ve | 2 | 3.8 | 39 | 83.0 | |||||
| mCIM +ve | 51 | 98.1 | 26 | 55.3 | 98.1 | 44.7 | 66.2 | 95.5 | 72.7 |
| mCIM -ve | 1 | 1.9 | 21 | 44.7 | |||||
Abbreviations: MHT, modified Hodge test; eCIM, EDTA-modified carbapenem inactivation method; mCIM, modified carbapenem inactivation method; PPV, positive predictive value; NPV, negative predictive value; VAP, ventilator-associated pneumonia; +ve-positive.