title: Evaluation of serological diagnostic tests for typhoid fever in Papua New Guinea using a composite reference standard.
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.
authors.affiliation: Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea.
authors.forename: Valentine
authors.initials: V
authors.lastname: Siba
authors.forename: Paul F
authors.initials: PF
authors.lastname: Horwood
authors.forename: Kilagi
authors.initials: K
authors.lastname: Vanuga
authors.forename: Johanna
authors.initials: J
authors.lastname: Wapling
authors.forename: Rebecca
authors.initials: R
authors.lastname: Sehuko
authors.forename: Peter M
authors.initials: PM
authors.lastname: Siba
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Greenhill
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003365:Costs and Cost Analysis; D003955:Diagnostic Tests, Routine / Q000191:economics / Q000379:methods* / Q000592:standards; D005260:Female; D005334:Fever / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D010219:Papua New Guinea; D012015:Reference Standards; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000191:economics / Q000379:methods / Q000592:standards; D014435:Typhoid Fever / Q000175:diagnosis* / Q000473:pathology; D055815:Young Adult