title: Field evaluation of a real-time fluorescence loop-mediated isothermal amplification assay, RealAmp, for the diagnosis of malaria in Thailand and India.
abstract: BACKGROUND
  To eliminate malaria, surveillance for submicroscopic infections is needed. Molecular methods can detect submicroscopic infections but have not hitherto been amenable to implementation in surveillance programs. A portable loop-mediated isothermal amplification assay called RealAmp was assessed in 2 areas of low malaria transmission.
  
  
  METHODS
  RealAmp was evaluated in 141 patients from health clinics in India (passive surveillance) and in 127 asymptomatic persons in Thailand (active surveillance). The diagnostic validity, precision, and predictive value of RealAmp were determined using polymerase chain reaction (PCR) as the reference method. A pilot study of RealAmp was also performed on samples from patients presenting at a Thai health center.
  
  
  RESULTS
  A total of 96 and 7 positive cases were detected in India and Thailand, respectively, via PCR. In comparison with nested PCR, the sensitivity and specificity of RealAmp in India were 94.8% (95% confidence interval [CI], 88.3%-98.3%) and 100% (95% CI, 92.1%-100%), respectively, with correct identification of all 5 Plasmodium vivax cases. In Thailand, compared with pooled real-time PCR, RealAmp demonstrated 100% sensitivity (95% CI, 59.0%-100%) and 96.7% specificity (95% CI, 91.7%-99.1%). Testing at the health center demonstrated RealAmp's potential to serve as a point-of-care test with results available in 30-75 minutes.
  
  
  CONCLUSIONS
  RealAmp was comparable to PCR in detecting malaria parasites and shows promise as a tool to detect submicroscopic infections in malaria control and elimination programs worldwide.
authors.affiliation: Department of Epidemiology, Gillings School of Global Public Health.
authors.forename: Jaymin C
authors.initials: JC
authors.lastname: Patel
authors.affiliation: Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Naomi W
authors.initials: NW
authors.lastname: Lucchi
authors.affiliation: Regional Medical Research Centre for Tribals, Jabalpur, India.
authors.forename: Priyanka
authors.initials: P
authors.lastname: Srivastava
authors.affiliation: Division of Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill.
authors.forename: Jessica T
authors.initials: JT
authors.lastname: Lin
authors.affiliation: Bureau of Vector-Borne Diseases, Ministry of Public Health, Nonthaburi, Thailand.
authors.forename: Rungniran
authors.initials: R
authors.lastname: Sug-Aram
authors.affiliation: Bureau of Vector-Borne Diseases, Ministry of Public Health, Nonthaburi, Thailand.
authors.forename: Supannee
authors.initials: S
authors.lastname: Aruncharus
authors.affiliation: Regional Medical Research Centre for Tribals, Jabalpur, India.
authors.forename: Praveen K
authors.initials: PK
authors.lastname: Bharti
authors.affiliation: Regional Medical Research Centre for Tribals, Jabalpur, India.
authors.forename: Man M
authors.initials: MM
authors.lastname: Shukla
authors.affiliation: Bureau of Vector-Borne Diseases, Ministry of Public Health, Nonthaburi, Thailand.
authors.forename: Kanungnit
authors.initials: K
authors.lastname: Congpuong
authors.affiliation: Bureau of Vector-Borne Diseases, Ministry of Public Health, Nonthaburi, Thailand.
authors.forename: Wichai
authors.initials: W
authors.lastname: Satimai
authors.affiliation: Regional Medical Research Centre for Tribals, Jabalpur, India.
authors.forename: Neeru
authors.initials: N
authors.lastname: Singh
authors.affiliation: Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Venkatachalam
authors.initials: V
authors.lastname: Udhayakumar
authors.affiliation: Department of Epidemiology, Gillings School of Global Public Health.
authors.forename: Steven R
authors.initials: SR
authors.lastname: Meshnick
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D007223:Infant; D016778:Malaria, Falciparum / Q000175:diagnosis* / Q000453:epidemiology / Q000469:parasitology; D016780:Malaria, Vivax / Q000175:diagnosis* / Q000453:epidemiology / Q000469:parasitology; D008297:Male; D008875:Middle Aged; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D012680:Sensitivity and Specificity; D013785:Thailand / Q000453:epidemiology; D055815:Young Adult
keywords: LAMP; Plasmodium falciparum; Plasmodium vivax; RealAmp; diagnosis; elimination; loop-mediated isothermal amplification; low-transmission; malaria; positive predictive value; sensitivity; specificity; surveillance