This study was undertaken to estimate the prevalence of hepatitis B virus exposure (HBV) in the population of Ireland, by using oral fluid (saliva) collection by post for hepatitis B anti-core antibody (anti-HBc). The sampling frame used was the Register for 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. The study received a good response rate (60.4%), and more than 98% of the 1738 specimens were suitable for testing. The prevalence of anti-HBc in the Irish population was estimated to be .51%. The observed design effect was 1.29. From a literature review, 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 future applications in epidemiological research.