Comparing Health in Europe based on Dried Blood Spot Samples

SHARE, a pan-European panel study of about 85,000 individuals aged 50+ in 27 Continental European countries and Israel, has collected dried blood spot (DBS) samples from approximately 27,000 respondents in 13 countries. Laboratory results from DBS assays cannot be directly compared to the results one would obtain from assays of venous plasma samples using standard laboratory methods. DBS values of, e.g., total cholesterol, have both a larger mean and a larger variance. This paper shows that conventional lab-based adjustment formulae do not suffice to account for fieldwork conditions which may affect the quality of DBS taken in a survey like SHARE. We therefore performed structured validations in the laboratory which mimicked the SHARE fieldwork conditions. We use these validations to establish structural conversion formulae applicable to the SHARE populations which estimate the value that we would have obtained had it been feasible to analyze the donor’s venous blood with standard analytical methods for plasma or wet blood.