title: Oral fluid collection by post for viral antibody testing.
abstract: BACKGROUND
  The objective of this study was to estimate the prevalence of hepatitis B virus exposure (HBV) in the population of the Republic of Ireland, by using oral fluid (saliva) collection by post for hepatitis B anti-core antibody (anti-HBc). This paper discusses the methodological approach used and the strategies that were adopted to improve response rates.
  
  
  METHODS
  The sampling frame used was the Register of Electors for Irish parliamentary elections. A multistage stratified cluster sample was taken, and a total of 962 households were selected nationally. A four-letter approach was employed for sample collection. Households received an initial letter outlining the purpose of the study. This was followed by a letter containing six swabs for oral fluid collection, along with easy-to-follow instructions. Non-respondents received two reminder letters, and were also telephoned where possible. A telephone helpline was provided. All testing was anonymous and unlinked.
  
  
  RESULTS
  The study achieved a good household response rate (60.4%), and more than 98% of the 1738 specimens received were suitable for testing. The prevalence of anti-HBc in the Irish population was estimated to be 0.51%. The observed design effect was 1.29.
  
  
  CONCLUSIONS
  From a review of the literature, this is the first study where a representative sample of a national population was asked to self-collect oral fluid samples and return these by post for serological testing. The technique may have many future applications in epidemiological research.
authors.affiliation: Department of Public Health, ERHA, Dr Steevens Hospital, Dublin 8, Ireland.
authors.forename: T
authors.initials: T
authors.lastname: O'Connell
authors.forename: L
authors.initials: L
authors.lastname: Thornton
authors.forename: D
authors.initials: D
authors.lastname: O'Flanagan
authors.forename: A
authors.initials: A
authors.lastname: Staines
authors.forename: J
authors.initials: J
authors.lastname: Connell
authors.forename: S
authors.initials: S
authors.lastname: Dooley
authors.forename: G
authors.initials: G
authors.lastname: McCormack
mesh_terms: D000328:Adult; D006509:Hepatitis B / Q000453:epidemiology*; D006801:Humans; D007494:Ireland / Q000453:epidemiology; D011159:Population Surveillance / Q000379:methods*; D011177:Postal Service; D012463:Saliva / Q000821:virology*; D016036:Seroepidemiologic Studies