Oral fluid collection by post--a pilot study of two approaches

This pilot study aimed to assess the feasibility of the postal collection of oral fluid samples for surveillance purposes and the effect of two different approaches on the response rates. This cross-sectional, antibody prevalence study collected oral fluid samples and questionnaire data from randomly selected individuals, aged under 45 y, through the post. The individuals were recruited from four general practice registers. In a one stage approach patients were sent the oral fluid kit with the initial invitation letter. In a two stage approach the kits were sent out after written consent had been received. There was little difference in the overall response rates between the two approaches (38% two stage and 41% one stage), though the response rate for the one stage approach was 10% higher in the under-20-y-olds in practices from areas of greater deprivation. The low response partly reflected poor uptake in young adults who may need to be approached through more targeted surveys. In the other age groups additional reminders could prove a cost-effective way of increasing the response rate further.