A simple blood test may be capable of detecting Alzheimer’s disease decades before symptoms emerge, according to recent research. In parallel, a new brain imaging technique could identify early signs of the disease more effectively than existing methods, experts say. These advances are being viewed as promising steps toward earlier diagnosis, which could improve treatment outcomes.

The findings come from two separate studies conducted in the United States and Canada. The first, led by the University of California, examined blood samples from 1,350 cognitively healthy adults with an average age of 61. Researchers measured levels of amyloid-beta plaques and phosphorylated tau proteins—biomarkers linked to Alzheimer’s. The study revealed that individuals with higher concentrations of these proteins exhibited poorer cognitive performance and diminished memory and information processing abilities.

Authors noted that these results support the hypothesis that Alzheimer’s pathology begins many years before clinical symptoms manifest. They highlighted the potential of plasma biomarkers in enabling earlier detection of the disease. A similar blood test was approved last year by the U.S. Food and Drug Administration, but it is not yet incorporated into NHS diagnostic protocols.

The ability to identify Alzheimer’s before symptom onset could impact treatment decisions, especially regarding two pharmaceuticals currently licensed in the UK. The drugs, donanemab and lecanemab—produced by Eli Lilly and Eisai respectively—have demonstrated the capacity to slow disease progression by up to six months in patients with early-stage symptomatic Alzheimer’s. However, the National Institute for Health and Care Excellence (NICE) has so far declined to recommend these treatments for NHS use, citing concerns over their cost-effectiveness relative to the clinical benefits observed.

In the second study, researchers at the University of Pittsburgh assessed a novel positron emission tomography (PET) scan tracer, MK6240, against the standard tracer flortaucipir in 682 participants from the U.S. and Canada. This newer tracer identified more than twice as many early tau-positive cases among cognitively healthy adults compared to traditional methods, suggesting improved sensitivity for detecting early Alzheimer’s pathology.

Dr. Jacqui Hanley of Alzheimer’s Research UK commented that many individuals experience prolonged delays before receiving a dementia diagnosis, underscoring the importance of innovations such as blood tests and enhanced imaging techniques. Earlier detection opens the door to timely interventions and better management of the disease.

Alzheimer’s disease remains the leading cause of death in the UK, affecting over 520,000 people and claiming approximately 76,000 lives annually. While no cure exists, these diagnostic advances offer hope of identifying the disease earlier, which is critical for treatment and care planning.