A minimally invasive dried blood spot biomarker test for the detection of Alzheimer's disease pathology.

Blood biomarkers have emerged as accurate tools for detecting Alzheimer's disease (AD) pathology, offering a minimally invasive alternative to traditional diagnostic methods such as imaging and cerebrospinal fluid (CSF) analysis. Yet, the logistics surrounding venipuncture for blood collection, although considerably simpler than the acquisition of imaging and CSF, require precise processing and storage specific to AD biomarkers that are still guided by medical personnel. Consequently, limitations in their widescale use in research and broader clinical implementation exist. The DROP-AD project investigates the potential of dried plasma spot (DPS) and dried blood spot (DBS) analysis, derived from capillary blood, for detecting AD biomarkers, including phosphorylated tau at amino acid 217 (p-tau217), glial fibrillary acidic protein and neurofilament light. Here, 337 participants from 7 centers were included, with 304 participants providing paired capillary DPS or DBS and venous plasma samples. We observed strong correlations between DPS p-tau217 and venous plasma p-tau217 (r