title: Comparison of rapid diagnostic test Plasmotec Malaria-3, microscopy, and quantitative real-time PCR for diagnoses of Plasmodium falciparum and Plasmodium vivax infections in Mimika Regency, Papua, Indonesia.
abstract: BACKGROUND
  The World Health Organization recommends malaria be diagnosed by standard microscopy or rapid diagnostic test (RDT) before treatment. RDTs have been used with greater frequency in the absence of matching blood slide confirmation in the majority of RDT reported cases in Mimika Regency, Papua Province, Indonesia. Given the importance of RDT in current health system as point-of-care tool, careful validation of RDT product performance for providing accurate malaria diagnosis is critical.
  
  
  METHODS
  Plasmotec Malaria-3 (XW-P07) performance was evaluated by comparing it with paired blood film microscopy and quantitative real-time PCR (qPCR). Consecutive whole blood samples were derived from one clinic in Mimika as part of routine passive malaria case detection. RDT results were read by two trained technicians and interpreted by consensus. Expert microscopic examination of blood slides was cross-checked by observer-blinded second reader and a third examiner if discordant between examinations. qPCR was used as the 'gold standard', followed by microscopy for the outcome/disease variable. Comparison analysis included sensitivity (Sn), specificity (Sp), positive and negative predictive values (PPV & NPV), and other diagnostic screening performance measures for detecting Plasmodium falciparum and Plasmodium vivax infections.
  
  
  RESULTS
  Overall malaria positive samples from qPCR was 42.2% (175/415 samples); and from matching blood slides 40.5% (168/415) of which those infections with relatively low parasite densities ≤100/μl blood was 5.7% of P. falciparum and 16.5% of P. vivax samples examined. Overall RDT performance when compared with microscopy for detecting P. falciparum was Sn:92%, Sp:96.6%, PPV:88%, NPV:97.8%, Kappa:0.87; and for P. vivax Sn:72.9%, Sp:99.1%, PPV:95.4%, NPV:93.4%, Kappa:0.79. Overall RDT performance when compared with qPCR for detecting P. falciparum was Sn:92%, Sp:96.6%, PPV:88%, NPV:97.8%, Kappa:0.87; and for P. vivax Sn:66%, Sp:99.1%, PPV:95.4%, NPV:90.9%, Kappa:0.73.
  
  
  CONCLUSIONS
  Plasmotec Malaria-3 test showed good overall performance scores in precision for detecting P. falciparum, but lower values regarding sensitivity and negative likelihood ratio for detecting P. vivax, a finding partly associated with greater frequency of lower density P. vivax infections compared to P. falciparum in this study. In particular, the negative likelihood ratio (>0.1) for P. vivax detection indicates RDT lacked sufficient discriminating exclusion power falling below general acceptance criteria.
authors.affiliation: Public Health & Malaria Control, International SOS, PT. Freeport Indonesia, Kuala Kencana, Papua, Indonesia. fransisca.liony@gmail.com.
authors.forename: Liony
authors.initials: L
authors.lastname: Fransisca
authors.affiliation: Center for Tropical Medicine, Faculty of Medicine, Gadjah Mada University, Yogyakarta, Indonesia. harikusnanto@yahoo.com.
authors.forename: Josef Hari
authors.initials: JH
authors.lastname: Kusnanto
authors.affiliation: Public Health Department, Faculty of Medicine, Gadjah Mada University, Yogyakarta, Indonesia. tribaskorots@yahoo.com.
authors.forename: Tri Baskoro T
authors.initials: TB
authors.lastname: Satoto
authors.affiliation: Public Health & Malaria Control, International SOS, PT. Freeport Indonesia, Kuala Kencana, Papua, Indonesia. bonisebayang@gmail.com.
authors.forename: Boni
authors.initials: B
authors.lastname: Sebayang
authors.affiliation: Public Health & Malaria Control, International SOS, PT. Freeport Indonesia, Kuala Kencana, Papua, Indonesia. _suprianto@fmi.com.
authors.lastname: Supriyanto
authors.affiliation: Public Health & Malaria Control, International SOS, PT. Freeport Indonesia, Kuala Kencana, Papua, Indonesia. eko_andriyan@fmi.com.
authors.forename: Eko
authors.initials: E
authors.lastname: Andriyan
authors.affiliation: Public Health & Malaria Control, International SOS, PT. Freeport Indonesia, Kuala Kencana, Papua, Indonesia. bangs_michael@yahoo.com.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Bangs
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003955:Diagnostic Tests, Routine / Q000379:methods*; D006801:Humans; D007214:Indonesia; D007223:Infant; D016778:Malaria, Falciparum / Q000175:diagnosis* / Q000469:parasitology; D016780:Malaria, Vivax / Q000175:diagnosis* / Q000469:parasitology; D008853:Microscopy / Q000592:standards*; D008875:Middle Aged; D010963:Plasmodium falciparum / Q000302:isolation & purification; D010966:Plasmodium vivax / Q000302:isolation & purification; D060888:Real-Time Polymerase Chain Reaction; D055815:Young Adult