title: Sensitive and inexpensive molecular test for falciparum malaria: detecting Plasmodium falciparum DNA directly from heat-treated blood by loop-mediated isothermal amplification.
abstract: BACKGROUND
  Malaria is one of the most important parasitic infections in humans. A sensitive diagnostic test for malaria that could be applied at the community level could be useful in programs to control the disease. The aim of the present work was to develop a simple, inexpensive molecular test for Plasmodium falciparum.
  
  
  METHODS
  Blood was collected from controls (n = 100) and from patients diagnosed with falciparum malaria infection (n = 102), who were recruited to the study. Heat-treated blood samples were tested by a loop-mediated isothermal amplification (LAMP) assay for P. falciparum. Results were interpreted by a turbidity meter in real time or visually at the end of the assay. To evaluate the assay, DNA from these samples was purified and tested by PCR. Results from the LAMP and PCR assays were compared.
  
  
  RESULTS
  The LAMP assay detected P. falciparum directly from heat-treated blood. The quantitative data from the assay correlated to the parasite counts obtained by blood-film microscopic analyses. When we used the PCR assay as the comparison method, the sensitivity and specificity of the LAMP assay were 95% and 99%, respectively.
  
  
  CONCLUSIONS
  Unlike PCR, the LAMP assay does not require purified DNA for efficient DNA amplification, thereby reducing the cost and turnaround time for P. falciparum diagnosis. The assay requires only basic instruments, and assay positivity can be verified by visual inspection.
authors.affiliation: Department of Microbiology, The University of Hong Kong, Hong Kong SAR. llmpoon@hkucc.hku.hk
authors.forename: Leo L M
authors.initials: LL
authors.lastname: Poon
authors.forename: Bonnie W Y
authors.initials: BW
authors.lastname: Wong
authors.forename: Edmund H T
authors.initials: EH
authors.lastname: Ma
authors.forename: Kwok H
authors.initials: KH
authors.lastname: Chan
authors.forename: Larry M C
authors.initials: LM
authors.lastname: Chow
authors.forename: Wimal
authors.initials: W
authors.lastname: Abeyewickreme
authors.forename: Noppadon
authors.initials: N
authors.lastname: Tangpukdee
authors.forename: Kwok Y
authors.initials: KY
authors.lastname: Yuen
authors.forename: Yi
authors.initials: Y
authors.lastname: Guan
authors.forename: Sornchai
authors.initials: S
authors.lastname: Looareesuwan
authors.forename: J S Malik
authors.initials: JS
authors.lastname: Peiris
mesh_terms: D000818:Animals; D001483:Base Sequence; D002138:Calibration; D016054:DNA, Protozoan / Q000097:blood* / Q000235:genetics; D006358:Hot Temperature; D006801:Humans; D016778:Malaria, Falciparum / Q000097:blood / Q000175:diagnosis*; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000191:economics / Q000379:methods / Q000592:standards; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods*
chemical_list: D016054:DNA, Protozoan