title: Performance of SD Bioline Tsutsugamushi assays for the diagnosis of scrub typhus in Thailand.
abstract: OBJECTIVE
  To assess the diagnostic capacity of a commercially available test (SD Bioline Tsutsugamushi assay) to aid with the diagnosis of scrub typhus in febrile patients in Thailand.
  
  
  METHODS
  A commercially available lateral-flow-format immunochromatographic test (ICT) for the detection of O. tsutsugamushi IgM, IgG and IgA antibodies was evaluated, using archived serum samples from 102 laboratory confirmed scrub typhus patients and from 63 patients with other causes of fever as the negative control.
  
  
  RESULTS
  The sensitivity, specificity of this rapid immunochromatographic test were 66.7% (95% CI, 57.1 to 75.1%) and 98.4% (95% CI 91.5 to 99.7%) respectively. False positive ICT result occurred in one patient with influenza A infection. Among patients with scrub typhus, 17 out of 38 patients (44.7%, 95% CI 30.2 to 60.3%) with negative IgM antibody test by IFA (titer < 1:50) had positive ICT test. Compared to IFA IgG, 33 out of 54 patients (66.1%, 95% CI 47.8 to 72.9%) with negative IgG antibody test by IFA (titer < 1:50) had positive ICT test.
  
  
  CONCLUSIONS
  This rapid ICT test for the diagnosis of scrub typhus was more sensitive than the standard IFA in acute phase specimens.
authors.affiliation: Department of Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Saowaluk
authors.initials: S
authors.lastname: Silpasakorn
authors.forename: Duangdao
authors.initials: D
authors.lastname: Waywa
authors.forename: Siriwan
authors.initials: S
authors.lastname: Hoontrakul
authors.forename: Chuanpit
authors.initials: C
authors.lastname: Suttinont
authors.forename: Kitti
authors.initials: K
authors.lastname: Losuwanaluk
authors.forename: Yupin
authors.initials: Y
authors.lastname: Suputtamongkol
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002846:Chromatography, Affinity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011933:Reagent Kits, Diagnostic; D012612:Scrub Typhus / Q000175:diagnosis*; D012680:Sensitivity and Specificity; D013785:Thailand; D055815:Young Adult
chemical_list: D011933:Reagent Kits, Diagnostic