title: Evaluation of saliva as diagnostic materials for influenza virus infection by PCR-based assays.
abstract: BACKGROUND
  Immunochromatographic antigen tests have been widely used for detection of influenza virus; however its low sensitivity restricts the use of clinical materials other than nasopharyngeal swabs. Saliva is obtained non-invasively and has utility for diagnosis of influenza. Polymerase chain reaction (PCR) is not typically used for rapid testing because it is time consuming. We evaluated the utility of saliva as diagnostic materials for influenza virus infection by PCR-based assays.
  
  
  METHODS
  Nasopharyngeal swabs and saliva were simultaneously collected from 144 patients and investigated by reverse transcription-quantitative PCR (RT-qPCR) and droplet-RT-PCR.
  
  
  RESULTS
  Overall concordance of results from nasopharyngeal swabs and saliva were 95.8%. Influenza gene was detectable in less than 12min in saliva by the droplet-RT-PCR. Saliva as well as nasopharyngeal swabs contained more than 1×10(2) copies/μl of the influenza gene. About half of the patients provided positive results in nasopharyngeal swabs and saliva within 24h from the onset of the symptoms.
  
  
  CONCLUSIONS
  The study demonstrates that saliva can be used as an alternative specimen source to nasopharyngeal swabs. When rapid PCR assay including RNA extraction to be full-automation in a miniaturized machine, point-of-care test based on PCR may be realized using saliva without restriction of materials.
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan.
authors.forename: Akane
authors.initials: A
authors.lastname: Sueki
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan. Electronic address: kmatsuda@shinshu-u.ac.jp.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Matsuda
authors.affiliation: Core Technology Development Center, Seiko Epson Corporation, Suwa, Japan.
authors.forename: Akemi
authors.initials: A
authors.lastname: Yamaguchi
authors.affiliation: Core Technology Development Center, Seiko Epson Corporation, Suwa, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Uehara
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan.
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Sugano
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Uehara
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Honda
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology*; D007251:Influenza, Human / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009305:Nasopharynx / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012463:Saliva / Q000378:metabolism*; D055815:Young Adult
keywords: Droplet-RT-PCR; Influenza virus; One-step real-time RT-PCR; Rapid detection; Saliva