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Table 2 Primary analysis for the performance* of the Widal test for typhoid fever diagnosis (n = 1680)

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

Widal titer Sensitivity (95%CI) Specificity (95%CI) Positive Predictive Value Negative Predictive Value
TH ≥1:80 12/16, 0.75
(0.51-0.90)
1630/1664, 0.98
(0.97-0.99)
12/46, 0.26 1630/1634, 1.00
TH ≥1:160 11/16, 0.69
(0.44-0.86)
1639/1664, 0.98
(0.98-0.99)
11/36, 0.31 1639/1644, 1.00
TH ≥1:320 6/16, 0.38
(0.18-0.61)
1646/1664, 0.99
(0.98-0.99)
6/24, 0.25 1646/1656, 0.99
TO ≥1:80 11/16, 0.69
(0.44-0.86)
1631/1664, 0.98
(0.97-0.99)
11/44, 0.25 1631/1636, 1.00
TO ≥1:160 10/16, 0.63
(0.39-0.82)
1640/1664, 0.99
(0.98-0.99)
10/34, 0.29 1640/1646, 1.00
TO ≥1:320 6/16, 0.38
(0.18-0.61)
1652/1664, 0.99
(0.99-1.00)
6/18, 0.33 1652/1662, 0.99
  1. *The values were calculated using culture-confirmed typhoid fever cases (group 1; n = 16) as the true positives and those cases from which S. typhi were not isolated from blood culture (groups 2, 3, and 4; n = 1664) as the true negatives.