Bulletin of the World Health Organization

Sensitivity and specificity of typhoid fever rapid antibody tests for laboratory diagnosis at two sub-Saharan African sites

Karen H Keddy, Arvinda Sooka, Maupi E Letsoalo, Greta Hoyland, Claire Lise Chaignat, Anne B Morrissey & John A Crump

Volume 89, Number 9, September 2011, 640-647

Table 3. Predictive values of four rapid diagnostic tests for typhoid fever as determined by comparison with blood culture results under assumed pretest probabilities of 5% and 50%

Kit Pretest probability
5%
50%
PPV
% (95% CI)
NPV
% (95% CI)
PPV
% (95% CI)
NPV
% (95% CI)
Cromotest® O : semiquantitative slide agglutination 4.9 (4.5–5.4) 93.3 (60.4–99.2) 49.7 (47.4–51.9) 42.5 (7.4–87.2)
Cromotest® H : semiquantitative slide agglutination 7.8 (5.4–11.1) 98.0 (96.3–98.9) 61.6 (52.1–70.4) 71.8 (57.6–82.6)
Cromotest® O: single tube Widal 4.7 (4.1–5.4) 91.2 (70.0–97.9) 48.4 (45.0–51.8) 35.2 (10.9–70.6)
Cromotest® H: single tube Widal 5.5 (4.7–6.4) 98.2 (92.8–99.6) 52.5 (48.6–56.3) 74.0 (40.5– 2.3)
TUBEX® 11.0 (6.6–17.9) 98.0 (96.8–98.7) 70.2 (57.3–80.5) 71.9 (61.4–80.4)
Typhidot® IgM 9.1 (5.8–14.0) 97.9 (96.4–98.8) 65.6 (54.0–75.6) 70.8 (58.2–80.9)
Typhidot® IgG 11.0 (6.3–18.4) 97.8 (96.4–98.6) 70.0 (56.0–81.1) 69.6 (58.7–78.6)

CI, confidence interval; NPV, negative predictive value; PPV, positive predictive value.