title: Field Evaluation of a High Throughput Loop Mediated Isothermal Amplification Test for the Detection of Asymptomatic Plasmodium Infections in Zanzibar.
abstract: BACKGROUND
  New field applicable diagnostic tools are needed for highly sensitive detection of residual malaria infections in pre-elimination settings. Field performance of a high throughput DNA extraction system for loop mediated isothermal amplification (HTP-LAMP) was therefore evaluated for detecting malaria parasites among asymptomatic individuals in Zanzibar.
  
  
  METHODS
  HTP-LAMP performance was evaluated against real-time PCR on 3008 paired blood samples collected on filter papers in a community-based survey in 2015.
  
  
  RESULTS
  The PCR and HTP-LAMP determined malaria prevalences were 1.6% (95%CI 1.3-2.4) and 0.7% (95%CI 0.4-1.1), respectively. The sensitivity of HTP-LAMP compared to PCR was 40.8% (CI95% 27.0-55.8) and the specificity was 99.9% (CI95% 99.8-100). For the PCR positive samples, there was no statistically significant difference between the geometric mean parasite densities among the HTP-LAMP positive (2.5 p/μL, range 0.2-770) and HTP-LAMP negative (1.4 p/μL, range 0.1-7) samples (p = 0.088). Two lab technicians analysed up to 282 samples per day and the HTP-LAMP method was experienced as user friendly.
  
  
  CONCLUSIONS
  Although field applicable, this high throughput format of LAMP as used here was not sensitive enough to be recommended for detection of asymptomatic low-density infections in areas like Zanzibar, approaching malaria elimination.
authors.affiliation: Centre for Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.|Unit of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Berit
authors.identifier: http://orcid.org/0000-0002-9216-5616
authors.initials: B
authors.lastname: Aydin-Schmidt
authors.affiliation: Centre for Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Ulrika
authors.initials: U
authors.lastname: Morris
authors.affiliation: Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland.
authors.forename: Xavier C
authors.initials: XC
authors.lastname: Ding
authors.affiliation: Centre for Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Irina
authors.initials: I
authors.lastname: Jovel
authors.affiliation: Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, Tanzania.
authors.forename: Mwinyi I
authors.initials: MI
authors.lastname: Msellem
authors.affiliation: Centre for Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Daniel
authors.initials: D
authors.lastname: Bergman
authors.affiliation: Centre for Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Atiqul
authors.initials: A
authors.lastname: Islam
authors.affiliation: Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, Tanzania.
authors.forename: Abdullah S
authors.initials: AS
authors.lastname: Ali
authors.affiliation: Department of Clinical Parasitology, Hospital for Tropical Diseases, University College London Hospitals, NHS Foundation Trust, London, United Kingdom.
authors.forename: Spencer
authors.initials: S
authors.lastname: Polley
authors.affiliation: Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland.
authors.forename: Iveth J
authors.initials: IJ
authors.lastname: Gonzalez
authors.affiliation: Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden.
authors.forename: Andreas
authors.initials: A
authors.lastname: Mårtensson
authors.affiliation: Centre for Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Björkman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D058345:Asymptomatic Infections / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008288:Malaria / Q000175:diagnosis* / Q000453:epidemiology / Q000469:parasitology; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D010961:Plasmodium / Q000235:genetics* / Q000302:isolation & purification; D015995:Prevalence; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D013636:Tanzania / Q000453:epidemiology; D055815:Young Adult