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Table 4 Diagnostic performance of the study RDTs for all pooled cases of enteric fever and for Salmonella Typhi infections only

From: Etiological spectrum of persistent fever in the tropics and predictors of ubiquitous infections: a prospective four-country study with pooled analysis

  SD Bioline Salmonella typhi IgG/IgM Test-itTM Typhoid IgM Lateral Flow Assay Typhidot Rapid IgM
Enteric fever
 Sensitivity 5/26 (19; 9–38) 8/15 (53; 30–75) 12/26 (46; 29–65)
 Specificity 1867/1892 (98.7; 97.7–99.7) 689/771 (89.4; 87.0–91.0) 1605/1862 (86.2; 84.7–87.6)
 Positive likelihood ratio 14.6 5.0 3.3
 Negative likelihood ratio 0.82 0.52 0.62
 Post-test probability if positive test (pre-test = 1.8%)a 21.1% 8.4% 5.8%
 Post-test probability if negative test (pre-test = 1.8%)a 1.5% 0.9% 1.1%
Salmonella Typhi infection
 Sensitivity 5/17 (29; 13–53) 6/9 (67; 35–88) 10/17 (59; 36–78)
 Specificity 1876/1901 (98.7; 97.7–99.7) 693/777 (89.2; 86.6–91.5) 1612/1871 (86.2; 84.7–87.6)
 Positive likelihood ratio 22.4 6.2 4.2
 Negative likelihood ratio 0.70 0.37 0.48
 Post-test probability of if positive test (pre-test = 1.2%)a 21.4% 7.0% 4.9%
 Post-test probability if negative test (pre-test = 1.2%)a 0.9% 0.5% 0.6%
  1. Sensitivity and specificity are reported as n/n (%; 95% confidence interval)
  2. a Pre-test probabilities indicate the frequency of enteric fever (i.e., 34/1922, 1.8%) and S. Typhi infection (i.e., 23/1922, 1.2%) in the study cohort