Capillary blood sampling from fingersticks demonstrates equivalent accuracy to traditional venous draws for detecting key Alzheimer's biomarkers including phosphorylated tau-217 (p-tau217), neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP). The correlation between sampling methods suggests capillary testing could transform early dementia screening accessibility.
This validation addresses a critical bottleneck in Alzheimer's detection. Current biomarker testing requires venipuncture and specialized laboratory processing, limiting screening to clinical settings and creating barriers for routine monitoring. Capillary sampling could enable point-of-care testing, home collection, and population-wide screening programs. The approach builds on recent advances in ultrasensitive immunoassays that can detect femtomolar concentrations of neurodegeneration markers in tiny blood volumes. However, technical challenges remain around sample stability, standardization across devices, and ensuring reproducibility in diverse populations. The methodology needs validation across different stages of cognitive decline and in populations with varying vascular health. If these hurdles are overcome, fingerstick biomarker testing could democratize early Alzheimer's detection, potentially enabling intervention during presymptomatic phases when treatments may be most effective.
