SHARE Working Paper Series 47-2020: Collection of Dried Blood Spots in the Survey of Health, Ageing and Retirement in Europe (SHARE): From implementation to blood-marker analyses

Assessment of circulating apoE4 levels from dried blood spot samples in a large survey setting

“…We combined the apoE4 assay with nine additional markers of interest for a broad assessment of the immune response in aging. 11 To foreshadow the results, our assay provided a range of values depicted in two distributions, in line with the protein being highly detectable in carriers of the APOE ε4 allele and at the level of noise in non-carriers. To validate this interpretation further, we performed a targeted DNA analysis for the two single nucleotide polymorphisms (SNPs) defining the APOE genotype in a sub-sample of deceased SHARE participants to test our hypothesis that the two distributions corresponded to apoE4 positive and apoE4 negative and successfully generated a cut-off with excellent diagnostic accuracy.…”

“…Extracts from a large subset ( N = 15,974) of the available DBS samples were obtained and assayed using a 10‐plex immunoassay using preprinted Meso Scale plates (Meso Scale Diagnostics [MSD]) coated with antibodies specific for apoE4 and nine other biomarkers reported elsewhere. 11 As validation of the preprinted 10‐plex, cross‐reactivity was tested by adding one calibrator protein at a time together with all 10 detection antibodies to check for non‐specific binding (NSB) in the nine remaining assays (NSB = [NSB signal – background signal]/[specific signal – background signal]). None of the 10 calibrators interfered significantly with the remaining nine assays (NSB < 5%).…”

“…Extracts from a large subset (N = 15,974) of the available DBS samples were obtained and assayed using a 10-plex immunoassay using preprinted Meso Scale plates (Meso Scale Diagnostics [MSD]) coated with antibodies specific for apoE4 and nine other biomarkers reported elsewhere. 11 As validation of the preprinted 10-plex, For analytical characterization, intra-assay variations (apoE4:…”

“…We combined the apoE4 assay with nine additional markers of interest for a broad assessment of the immune response in aging. 11 …”