A diagnostic method has been developed that can determine Alzheimer's disease using just a few drops of blood and precisely ascertain the extent of its progression. It is expected that doctors will be able to provide tailored treatments suitable for each stage of the disease.
A joint research team from Stanford University in the United States and Lund University in Sweden noted on the 31st (local time) in the international journal "Nature Medicine" that they have developed a blood test technology capable of precisely measuring the accumulation of tau protein, which is considered one of the causes of Alzheimer's disease.
Tau protein, along with amyloid beta (Aβ) protein, is regarded as a cause of Alzheimer's disease. Tau serves as a structural protein maintaining the integrity of nerve cells, but when it detaches from its original position and accumulates inside cells, it causes cognitive function issues. Amyloid beta is originally a protective protein for nerve cells, but when it separates and forms clumps, it actually damages nerve cells.
Existing blood tests are limited to merely determining the presence of Alzheimer's disease. Positron emission tomography (PET), which is primarily used for Alzheimer's diagnosis, can accurately confirm the accumulation of amyloid beta or tau proteins but has the drawback of being time-consuming and costly. The newly developed technology allows for a simple method to distinguish the disease's progression from the early stages of Alzheimer's to mild cognitive impairment and dementia, the researchers said.
The research team analyzed blood from 902 participants, including symptom-free individuals, those in the early stage of mild cognitive impairment, and those in the late stages of severe dementia. The result confirmed that tau protein fragments were detected only in the blood of Alzheimer's patients and that the concentration of the protein correlates with the severity of tau tangles in the brain and dementia symptoms.
In contrast, individuals with cognitive impairment due to other diseases exhibited low levels of tau. The research team stated they successfully determined Alzheimer's progression stages in patients with 92% accuracy using this blood test.
The research team noted that utilizing blood tests could allow for the prescription of Alzheimer's medications tailored to patients without the need for PET scans, enabling cost savings in medical expenses and swift diagnoses. Both "Leqembi" (generic name lecanemab), co-developed by Japan's Eisai and the U.S. company Biogen, and "donanemab" from Eli Lilly in the U.S. have been shown to delay the progression of Alzheimer's in early patients. Accurate knowledge of the progression stage of Alzheimer's patients is vital for prescribing new drugs.
Oskar Hansson, a professor of neurology at Lund University, who led the research, said, "With several countries recently approving Alzheimer's treatments, the need for efficient Alzheimer's diagnosis with high accuracy and low expense has become urgent." Co-author Tony Wyss-Coray, a professor at Stanford University, said, "This blood test can help identify the most suitable drugs for individual patients, as well as select appropriate participants for clinical trials, leading to accurate results in drug development."
However, there are suggestions that more research is needed to commercialize this blood test. Tara Spires-Jones, a professor of neurology at the University of Edinburgh in the UK, stated, "As this is currently the result of laboratory research and analysis, additional studies are required to make it practical and easy to use in clinical settings."
References
Nature Medicine (2025), DOI: https://doi.org/10.1038/s41591-025-03617-7