Table 6.
Validity of the presumptive case definition of leptospirosis among 147 possible cases for whom paired serum samples were obtained during the leptospirosis outbreak in Kegalle, Kandy and Matale, Sri Lanka, 2008*
| Parameter | Estimate | 95% CI |
|---|---|---|
| Sensitivity | 66.2% | 54.9–76.0 |
| Specificity | 89.0% | 79.8–94.3 |
| Positive predictive value | 86.0% | 74.7–92.7 |
| Negative predictive value | 72.2% | 62.2–80.4 |
| Diagnostic accuracy | 77.5% | 70.1–83.5 |
| Likelihood ratio of a positive test result | 6.04 | 4.63–7.88 |
| Likelihood ratio of a negative test result | 0.38 | 0.35–0.41 |
| Diagnostic odds | 15.93 | 6.62–38.3 |
*
Eighteen patients with equivocal results in the enzyme-linked immunosorbent assay (ELISA) and two patients in whom ELISA results were available were not included in analysis. CI = confidence interval.