Skip to main content

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*

From: Evaluation of the Widal tube agglutination test for the diagnosis of typhoid fever among children admitted to a rural hdospital in Tanzania and a comparison with previous studies

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
  1. *Group 1 were those with S. typhi isolated from blood culture (n = 16), group 2 were those with non-typhi serotypes of S. enterica (NTS) isolated from blood culture (n = 49), group 3 were those with pathogenic bacteria other than Salmonellae isolated from blood culture (n = 113), and group 4 were those whose blood culture yielded no bacterial pathogen (n = 1502).