Table 1.
The novel Clostridium difficile diagnostic assay loop-mediated isothermal amplification (LAMP; Illumigene) compared to cell culture cytotoxin B (CTBA) and/or toxigenic culture (TC) as the gold standarda
| Diagnostic assay | Diagnostic assay compared to CTBA plus TC |
|||||||
|---|---|---|---|---|---|---|---|---|
| Sensitivity |
Specificity |
PPV |
NPV |
|||||
| % (no. of specimens/total no.) | CI (%) | % (no. of specimens/total no.) | CI (%) | % (no. of specimens/total no.) | CI (%) | % (no. of specimens/total no.) | CI (%) | |
| LAMP | 98 (49/50) | 89–100 | 98 (218/222) | 95–99 | 92 (49/53) | 82–98 | 99 (218/219) | 97–100 |
| CTBA | 72 (36/50) | 57–84 | 100 (222/222) | 98–100 | 100 (36/36) | 90–100 | 94 (222/236) | 90–97 |
| TC | 100 (50/50) | 93–100 | 100 (222/222) | 98–100 | 100 (50/50) | 93–100 | 100 (222/222) | 98–100 |
a
One of the four specimens that tested positive by LAMP only was positive in an in-house rpoA PCR, indicating that both the sensitivity and specificity of the LAMP test are higher. PPV, positive predictive value; NPV, negative predictive value; CI, confidence interval.