title: Quality assurance of malaria rapid diagnostic tests used for routine patient care in rural Tanzania: microscopy versus real-time polymerase chain reaction.
abstract: BACKGROUND
  The World Health Organization (WHO) recommends parasitologic confirmation of suspected malaria cases before treatment. Due to the limited availability of quality microscopy services, this recommendation has become scalable following increased use of antigen-detecting malaria rapid diagnostic tests (RDTs) in many malaria-endemic countries. This study was carried out to monitor quality of RDT performance in selected health facilities using two quality assurance (QA) methods: reference microscopy and detection of parasite DNA by real-time quantitative polymerase chain reaction (qPCR) on dried blood spots (DBS).
  
  
  METHODS
  Blood samples for QA were collected from patients undergoing RDT for diagnostic confirmation of malaria during two to three consecutive days per month in 12 health facilities in rural Tanzania. Stained blood smears (BS) were first examined at the district hospitals (BS1) and then at a reference laboratory (BS2). Discordant BS1 and BS2 results prompted a third examination. Molecular analysis was carried out at the Ifakara Health Institute laboratory in Bagamoyo.
  
  
  RESULTS
  Malaria RDTs had a higher positivity rate (6.5%) than qPCR (4.2%) or microscopy (2.9% for BS1 and 2.5% for BS2). Poor correlation was observed between RDT and BS results: BS1 (K = 0.5), BS2 (K = 0.43) and qPCR (K = 0.45), challenging the utility of these tests for RDT QA. In addition, many challenges related to qPCR processing were recorded and long delays in obtaining QA test results for both microscopy and qPCR.
  
  
  CONCLUSIONS
  Overall there was limited agreement among the three diagnostic approaches and neither microscopy nor qPCR appear to be good QA options for RDTs under field conditions.
authors.affiliation: Health System Sciences, Ifakara Health Institute, PO Box 78373, Dar es Salaam, Tanzania. imasanja@ihi.or.tz.
authors.forename: Irene M
authors.initials: IM
authors.lastname: Masanja
authors.affiliation: Malaria Branch, Centers for Global Health, US Centers for Disease Control and Prevention, Atlanta, GA, USA. mmcmorrow@cdc.gov.|US Public Health Services, Rockville, Maryland, USA. mmcmorrow@cdc.gov.
authors.forename: Meredith L
authors.initials: ML
authors.lastname: McMorrow
authors.affiliation: Health System Sciences, Ifakara Health Institute, PO Box 78373, Dar es Salaam, Tanzania. mmaganga@ihi.or.tz.
authors.forename: Mussa B
authors.initials: MB
authors.lastname: Maganga
authors.affiliation: Health System Sciences, Ifakara Health Institute, PO Box 78373, Dar es Salaam, Tanzania. dsumari@ihi.or.tz.
authors.forename: Debora
authors.initials: D
authors.lastname: Sumari
authors.affiliation: Malaria Branch, Centers for Global Health, US Centers for Disease Control and Prevention, Atlanta, GA, USA. vudhayakumar@cdc.gov.
authors.forename: Venkatachalam
authors.initials: V
authors.lastname: Udhayakumar
authors.affiliation: Malaria Branch, Centers for Global Health, US Centers for Disease Control and Prevention, Atlanta, GA, USA. pgm9@cdc.gov.|US President Malaria Initiative (PMI), Dar es Salaam, United Republic of Tanzania. pgm9@cdc.gov.
authors.forename: Peter D
authors.initials: PD
authors.lastname: McElroy
authors.affiliation: Malaria Branch, Centers for Global Health, US Centers for Disease Control and Prevention, Atlanta, GA, USA. spkachur@cdc.gov.|US Public Health Services, Rockville, Maryland, USA. spkachur@cdc.gov.
authors.forename: S Patrick
authors.initials: SP
authors.lastname: Kachur
authors.affiliation: Malaria Branch, Centers for Global Health, US Centers for Disease Control and Prevention, Atlanta, GA, USA. nlucchi@cdc.gov.
authors.forename: Naomi W
authors.initials: NW
authors.lastname: Lucchi
mesh_terms: D003955:Diagnostic Tests, Routine / Q000379:methods* / Q000592:standards*; D008853:Microscopy; D005791:Patient Care; D011786:Quality Control; D060888:Real-Time Polymerase Chain Reaction; D013636:Tanzania