title: A critical assessment of two real-time PCR assays targeting the (SSU) rRNA and gdh genes for the molecular identification of Giardia intestinalis in a clinical laboratory.
abstract: BACKGROUND
  Giardiasis is an intestinal diarrhoeal illness caused by the flagellate protozoan parasite Giardia intestinalis. Molecular techniques for the identification of G. intestinalis have generally been shown to offer a better detection rate of the parasite than the traditional faecal concentration and microscopy techniques.
  
  
  OBJECTIVE
  The aim of this study was to critically assess the performance of a commercial and a published real-time PCR assay for their potential use as frontline tests for the diagnosis of giardiasis.
  
  
  METHODS
  A composite reference standard of enzyme immunoassay and rapid membrane test was used in a diagnostic accuracy study to assess the performance of Primerdesign's, and Verweij et al G. intestinalis real-time PCR assays, comparing them with the traditional ova, cysts and parasite microscopy test (OCP-M).
  
  
  RESULTS
  The Verweij real-time PCR used primers for the (SSU) rRNA gene, and produced a diagnostic sensitivity of 93.4% (95% CI 88.30% to 98.50%) and an efficiency of 100%. Primerdesign's real-time PCR used primers for the glutamate dehydrogenase gene and produced a diagnostic sensitivity of 61.5% (95% CI 51.50% to 71.50%) and an efficiency of 203%. The OCP-M sensitivity was 83.5% (95% CI 75.87% to 91.13%).
  
  
  CONCLUSIONS
  The Verweij real-time PCR was robust and the most sensitive assay suited for use as a first-line diagnostic test for giardiasis.
authors.forename: Samuel
authors.initials: S
authors.lastname: Boadi
authors.forename: Spencer D
authors.initials: SD
authors.lastname: Polley
authors.forename: Sally
authors.initials: S
authors.lastname: Kilburn
authors.forename: Graham A
authors.initials: GA
authors.lastname: Mills
authors.forename: Peter L
authors.initials: PL
authors.lastname: Chiodini
mesh_terms: D002138:Calibration; D016054:DNA, Protozoan / Q000235:genetics*; D005243:Feces / Q000469:parasitology; D016829:Giardia lamblia / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D005969:Glutamate Dehydrogenase / Q000235:genetics*; D006801:Humans; D007755:Laboratories, Hospital; D008853:Microscopy; D011237:Predictive Value of Tests; D015800:Protozoan Proteins / Q000235:genetics*; D012335:RNA, Ribosomal / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods* / Q000592:standards; D012015:Reference Standards; D015203:Reproducibility of Results
chemical_list: D016054:DNA, Protozoan; D015800:Protozoan Proteins; D012335:RNA, Ribosomal; D005969:Glutamate Dehydrogenase