Evaluation of serological diagnostic tests for typhoid fever in Papua New Guinea using a composite reference standard

Journal Publication ResearchOnline@JCU
Siba, Valentine;Horwood, Paul F.;Vanuga, Kilagi;Wapling, Johanna;Sehuko, Rebecca;Siba, Peter;Greenhill, Andrew R.
Abstract

Typhoid fever remains a major global health problem. A major impediment to improving outcomes is the lack of appropriate diagnostic tools, which have not significantly improved in low-income settings for 100 years. We evaluated two commercially available rapid diagnostic tests (Tubex and TyphiDot), a prototype (TyphiRapid TR-02), and the commonly used single-serum Widal test in a previously reported high-burden area of Papua New Guinea. Samples were collected from 530 outpatients with axillary temperatures of ≥37.5°C, and analysis was conducted on all malaria-negative samples (n = 500). A composite reference standard of blood culture and PCR was used, by which 47 participants (9.4%) were considered typhoid fever positive. The sensitivity and specificity of the Tubex (51.1% and 88.3%, respectively) and TyphiDot (70.0% and 80.1%, respectively) tests were not high enough to warrant their ongoing use in this setting; however, the sensitivity and specificity for the TR-02 prototype were promising (89.4% and 85.0%, respectively). An axillary temperature of ≥38.5°C correlated with typhoid fever (P = 0.014). With an appropriate diagnostic test, conducting typhoid fever diagnosis only on patients with high-grade fever could dramatically decrease the costs associated with diagnosis while having no detrimental impact on the ability to accurately diagnose the illness.

Journal

Clinical and Vaccine Immunology

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Volume

19

ISBN/ISSN

1556-679X

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Issue

11

Pages Count

5

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Publisher

American Society of Microbiology

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DOI

10.1128/CVI.00380-12