 Alzheimer's disease, AD, is a neurodegenerative condition characterized by progressive cognitive decline. Recent studies have suggested that AD should be viewed as a continuum rather than a discrete disease, with symptoms presenting at different levels of severity. Early detection of AD is important since no curative treatment exists, therefore, it is essential to develop diagnostic tools that are sensitive, non-invasive and cost-effective. Blood biomarkers have shown promise in this regard, but further research is needed to determine if they can accurately detect AD in its earliest stages. This article was authored by Jianfeng Yu, Kai Shao, Ku WAN, and others.