Table 4 Secondary analysis of the performance of a Widal anti-TH and -TO titer of ≥1:80 for typhoid fever diagnosis using group 1 as true positives and three different control groups as true negatives*
Control group | Sensitivity (95%CI) | Specificity (95%CI) | Positive Predictive Value | Negative Predictive Value |
|---|---|---|---|---|
TH titer ≥1:80: | ||||
Groups 2, 3, and 4 (n = 1664) | 12/16, 0.75 (0.51-0.90) | 1630/1664, 0.98 (0.97-0.99) | 12/46, 0.26 | 1630/1634, 1.00 |
Groups 2 and 3 (n = 162) | 12/16, 0.75 (0.51-0.90) | 154/162, 0.95 (0.91-0.97) | 12/20, 0.60 | 154/158, 0.97 |
Group 3 (n = 113) | 12/16, 0.75 (0.51-0.90) | 112/113, 0.99 (0.95-1.00) | 12/13, 0.92 | 112/116, 0.97 |
TO titer ≥1:80: | ||||
Groups 2, 3, and 4 (n = 1664) | 11/16, 0.69 (0.44-0.86) | 1631/1664, 0.98 (0.97-0.99) | 11/44, 0.25 | 1631/1636, 1.00 |
Groups 2 and 3 (n = 162) | 11/16, 0.69 (0.44-0.86) | 155/162, 0.96 (0.91-0.98) | 11/18, 0.61 | 155/160, 0.97 |
Group 3 (n = 113) | 11/16, 0.69 (0.44-0.86) | 113/113, 1.00 (0.97-1.00) | 11/11, 1.00 | 113/118, 0.96 |