Reference Intervals for Plasma Biomarkers of Alzheimer’s Disease

Several blood‐based biomarkers are emerging as potential screening, diagnostic, and prognostic tools for Alzheimer’s disease (AD), including: the ratio of amyloid beta 42 over 40 (Aβ42/40), reflecting the pathology of amyloid plaques; phosphorylated tau‐181 (p‐tau‐181), reflecting the formation of neurofibrillary tangles; neurofilament light (NF‐L), reflecting axonal damage observed in neurodegeneration; and glial fibrillary acidic protein (GFAP), reflecting neuroinflammation through astrocyte activation. A critical step in the translation of these biomarkers from research to clinical implementation is establishment of reference intervals derived from an appropriate population.