title: Highly sensitive detection of malaria parasitemia in a malaria-endemic setting: performance of a new loop-mediated isothermal amplification kit in a remote clinic in Uganda.
abstract: BACKGROUND
  Current malaria diagnostic tests, including microscopy and antigen-detecting rapid tests, cannot reliably detect low-density infections. Molecular methods such as polymerase chain reaction (PCR) are highly sensitive but remain too complex for field deployment. A new commercial molecular assay based on loop-mediated isothermal amplification (LAMP) was assessed for field use.
  
  
  METHODS
  Malaria LAMP (Eiken Chemical, Japan) was evaluated for samples from 272 outpatients at a rural Ugandan clinic and compared with expert microscopy, nested PCR, and quantitative PCR (qPCR). Two technicians performed the assay after 3 days of training, using 2 alternative blood sample-preparation methods and visual interpretation of results by fluorescence assay.
  
  
  RESULTS
  Compared with 3-well nested PCR, the sensitivity of both LAMP and single-well nested PCR was 90%; the microscopy sensitivity was 51%. For samples with a Plasmodium falciparum qPCR titer of ≥ 2 parasites/µL, LAMP sensitivity was 97.8% (95% confidence interval, 93.7%-99.5%). Most false-negative LAMP results involved samples with parasitemia levels detectable by 3-well nested PCR but very low or undetectable by qPCR.
  
  
  CONCLUSIONS
  Malaria LAMP in a remote Ugandan clinic achieved sensitivity similar to that of single-well nested PCR in a United Kingdom reference laboratory. LAMP dramatically lowers the detection threshold achievable in malaria-endemic settings, providing a new tool for diagnosis, surveillance, and screening in elimination strategies.
authors: Foundation for Innovative New Diagnostics, Uganda Ministry of Health, Kampala, Uganda.
authors: Heidi
authors: H
authors: Hopkins
authors: Iveth J
authors: IJ
authors: González
authors: Spencer D
authors: SD
authors: Polley
authors: Patrick
authors: P
authors: Angutoko
authors: John
authors: J
authors: Ategeka
authors: Caroline
authors: C
authors: Asiimwe
authors: Bosco
authors: B
authors: Agaba
authors: Daniel J
authors: DJ
authors: Kyabayinze
authors: Colin J
authors: CJ
authors: Sutherland
authors: Mark D
authors: MD
authors: Perkins
authors: David
authors: D
authors: Bell
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D019353:Endemic Diseases; D005260:Female; D006801:Humans; D016778:Malaria, Falciparum / Q000175:diagnosis* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D018512:Parasitemia / Q000175:diagnosis*; D010274:Parasitology / Q000379:methods*; D010963:Plasmodium falciparum / Q000302:isolation & purification*; D012424:Rural Population; D012680:Sensitivity and Specificity; D014454:Uganda; D055815:Young Adult
keywords: Africa; DNA; LAMP; PCR; Plasmodium falciparum; Uganda; diagnosis; loop-mediated isothermal amplification; malaria; molecular diagnosis; polymerase chain reaction; sensitivity and specificity
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