title: Field validity, reproducibility and feasibility of diagnostic tests for visceral leishmaniasis in rural Nepal.
abstract: OBJECTIVE
  To assess the field accuracy, reproducibility and feasibility of the formol gel test (FGT), the urine latex agglutination test (KAtex) and a rK39 antigen-based dipstick for the diagnosis of visceral leishmaniasis (VL) in rural Nepal.
  
  
  METHODS
  Patients with clinical suspicion of VL were recruited at Rangeli District Hospital (DH), a 15-bed government hospital located in south-eastern Nepal. FGT, KAtex and rK39 dipstick tests were performed on site and later repeated at a reference kala-azar diagnostic laboratory to assess reproducibility. Diagnosis of VL was confirmed by either a positive bone marrow aspirate examination or a positive direct agglutination test (DAT titre > or = 1:3200) in patients who later responded to anti-leishmanial therapy.
  
  
  RESULTS
  Of 155 patients initially recruited, 142 (85 with VL and 57 with another diagnosis) were included in the study. The sensitivity of the rK39 dipstick [89%; 95% confidence interval (CI): 81-94] was significantly higher than that of the KAtex (57%; 95% CI: 46-67) and the FGT (52%; 95% CI: 41-62). All three tests had a specificity of at least 90%. Agreement was higher for the rK39 dipstick (kappa = 0.87) than for the FGT (0.68) and the KAtex (0.43). All tests required < or = 20 min of actual work and < or = 40 min to obtain the results.
  
  
  CONCLUSIONS
  The rK39 dipstick was easy to do, more accurate and reproducible than other rapid diagnostic tests for VL in a DH of rural Nepal. It should be integrated into the field diagnostic algorithm of VL in this region and mechanisms to secure its availability should be found.
authors.affiliation: Travel and Migration Medicine Unit, Geneva University Hospital, Geneva, Switzerland. francois.chappuis@hcuge.ch
authors.forename: François
authors.initials: F
authors.lastname: Chappuis
authors.forename: Suman
authors.initials: S
authors.lastname: Rijal
authors.forename: Uma Kant
authors.initials: UK
authors.lastname: Jha
authors.forename: Philippe
authors.initials: P
authors.lastname: Desjeux
authors.forename: Bal Man Singh
authors.initials: BM
authors.lastname: Karki
authors.forename: Shekhar
authors.initials: S
authors.lastname: Koirala
authors.forename: Louis
authors.initials: L
authors.lastname: Loutan
authors.forename: Marleen
authors.initials: M
authors.lastname: Boelaert
mesh_terms: D000328:Adult; D000953:Antigens, Protozoan / Q000032:analysis; D003955:Diagnostic Tests, Routine / Q000379:methods*; D004202:Disinfectants; D019353:Endemic Diseases; D005240:Feasibility Studies; D005260:Female; D005557:Formaldehyde; D006801:Humans; D007159:Immunologic Tests / Q000379:methods; D007841:Latex Fixation Tests / Q000379:methods; D007898:Leishmaniasis, Visceral / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology; D008297:Male; D009390:Nepal / Q000453:epidemiology; D015203:Reproducibility of Results; D012423:Rural Health; D012680:Sensitivity and Specificity
chemical_list: D000953:Antigens, Protozoan; D004202:Disinfectants; D005557:Formaldehyde