title: The usefulness of rapid diagnostic tests in the new context of low malaria transmission in Zanzibar.
abstract: BACKGROUND
  We assessed if histidine-rich-protein-2 (HRP2) based rapid diagnostic test (RDT) remains an efficient tool for Plasmodium falciparum case detection among fever patients in Zanzibar and if primary health care workers continue to adhere to RDT results in the new epidemiological context of low malaria transmission. Further, we evaluated the performance of RDT within the newly adopted integrated management of childhood illness (IMCI) algorithm in Zanzibar.
  
  
  RESULTS
  We enrolled 3890 patients aged ≥ 2 months with uncomplicated febrile illness in this health facility based observational study conducted in 12 primary health care facilities in Zanzibar, between May-July 2010. One patient had an inconclusive RDT result. Overall 121/3889 (3.1%) patients were RDT positive. The highest RDT positivity rate, 32/528 (6.1%), was found in children aged 5-14 years. RDT sensitivity and specificity against PCR was 76.5% (95% CI 69.0-83.9%) and 99.9% (95% CI 99.7-100%), and against blood smear microscopy 78.6% (95% CI 70.8-85.1%) and 99.7% (95% CI 99.6-99.9%), respectively. All RDT positive, but only 3/3768 RDT negative patients received anti-malarial treatment. Adherence to RDT results was thus 3887/3889 (99.9%). RDT performed well in the IMCI algorithm with equally high adherence among children <5 years as compared with other age groups.
  
  
  CONCLUSIONS
  The sensitivity of HRP-2 based RDT in the hands of health care workers compared with both PCR and microscopy for P. falciparum case detection was relatively low, whereas adherence to test results with anti-malarial treatment was excellent. Moreover, the results provide evidence that RDT can be reliably integrated in IMCI as a tool for improved childhood fever management. However, the relatively low RDT sensitivity highlights the need for improved quality control of RDT use in primary health care facilities, but also for more sensitive point-of-care malaria diagnostic tools in the new epidemiological context of low malaria transmission in Zanzibar.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT01002066.
authors.affiliation: Malaria Research, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden ; Department of Medicine, Kungälv Hospital, Kungälv, Sweden.
authors.forename: Delér
authors.initials: D
authors.lastname: Shakely
authors.forename: Kristina
authors.initials: K
authors.lastname: Elfving
authors.forename: Berit
authors.initials: B
authors.lastname: Aydin-Schmidt
authors.forename: Mwinyi I
authors.initials: MI
authors.lastname: Msellem
authors.forename: Ulrika
authors.initials: U
authors.lastname: Morris
authors.forename: Rahila
authors.initials: R
authors.lastname: Omar
authors.forename: Xu
authors.initials: X
authors.lastname: Weiping
authors.forename: Max
authors.initials: M
authors.lastname: Petzold
authors.forename: Bryan
authors.initials: B
authors.lastname: Greenhouse
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Baltzell
authors.forename: Abdullah S
authors.initials: AS
authors.lastname: Ali
authors.forename: Anders
authors.initials: A
authors.lastname: Björkman
authors.forename: Andreas
authors.initials: A
authors.lastname: Mårtensson
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003955:Diagnostic Tests, Routine / Q000379:methods*; D005260:Female; D006801:Humans; D008288:Malaria / Q000175:diagnosis* / Q000635:transmission; D008297:Male; D010963:Plasmodium falciparum / Q000472:pathogenicity; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D013636:Tanzania
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