Collecting Biomarkers and Biological Samples Using Trained Interviewers. Lessons from a Pilot Study

This paper reports the design and outcomes of a pilot study for the UK Household Longitudinal Study (UKHLS), Understanding Society, to develop and test the feasibility of collection of biomarkers and biological samples by trained non-clinical interviewers. The dimensions reported are recruitment and training of interviewers, completeness, acceptability and time required for data collection, and quality of the biological samples. Some comparisons are made with measures conducted by nurses in the main UKHLS survey. Biomarkers included anthropometrics, blood pressure, grip strength and the collection of saliva and dried blood spots. There was no difficulty in recruitment, though a health requirement for hepatitis B vaccination restricted the pool of interviewers. Nine of ten interviewers were certified for collection of biomarkers. The interviewers completed a high proportion of the individual measures, including the biological samples. The median time for data collection by interviewers was higher than for nurses in the UKHLS. The biological samples were of sufficient quantity and quality to support planned analyses. Interviewers were successful in implementing the data collection protocols for the pilot study. Decisions about interviewer collection of biomarkers depend on study design characteristics.