Table 2.
Performance characteristics of individual testing modalities to detect toxigenic C. difficilea
| Parameter | Value |
||||
|---|---|---|---|---|---|
| BD GeneOhm | Meridian illumigene | TechLab Tox A/B II | Wampole Quik Chek Completeb |
||
| GDH | Tox A/B | ||||
| True positive (no.) | 20 | 20 | 11 | 23 | 10 |
| True negative (no.) | 118 | 114 | 115 | 115 | 118 |
| False positive (no.) | 0 | 4 | 3 | 0 | 0 |
| False negative (no.) | 1 | 1 | 10 | 1 | 11 |
| Sensitivity (%) | 95.2 | 95.2 | 52.4 | 95.8 | 47.6 |
| Specificity (%) | 100 | 96.6 | 97.5 | 100 | 100 |
| PPV (%) | 100 | 83.3 | 78.6 | 100 | 100 |
| NPV (%) | 99.2 | 99.1 | 92.0 | 99.1 | 91.5 |
a
n = 139.
b
A positive test result requires that both the GDH and Tox A/B components be positive. The sensitivity, specificity, PPV, and NPV of the Wampole Quik Chek Complete test were identical to the data listed for the Tox A/B component. The GDH component was assessed for the ability to detect any (toxigenic or nontoxigenic) C. difficile.