A study found that a few drops of blood pricked from a fingertip, dripped onto a paper card and dried, can be used to measure key signals of Alzheimer's disease.
An international research team including the University of Gothenburg in Sweden published the findings in the journal "Nature Medicine" on the 6th. People who have difficulty undergoing venous blood draws, brain scans, or cerebrospinal fluid tests are expected to be able to get tested more easily.
Alzheimer's disease, best known for memory loss, is the most common cause of dementia and occurs when certain proteins abnormally accumulate or change in the brain, damaging nerve cells.
But diagnosing Alzheimer's is not easy. Brain scans that detect changes in the brain face barriers of expense and access, and cerebrospinal fluid tests require inserting a needle into the lower back, which is highly invasive. For these reasons, patients and families often hesitate to get tested, and in areas with limited medical infrastructure, testing itself is often difficult.
Recently, methods that gauge Alzheimer's by measuring biomarkers in blood have drawn attention. Among them, the marker "p-tau217" is known as an indicator that indirectly shows in blood the changes that occur when abnormal proteins build up in the brain in Alzheimer's. However, who draws the sample, how it is collected, and under what conditions it is stored and transported can affect the reliability of the results, leaving real-world application as an unresolved task.
The researchers tested whether this problem could be solved with fingertip sampling and dried blood. They obtained a small amount of blood from a fingertip, dripped it onto a card to dry for storage, and later measured Alzheimer's-related proteins using analytical equipment.
In an experiment with 337 participants, p-tau217 levels measured from dried blood showed a very similar pattern to conventional venous blood test results.
In particular, results for p-tau217 measured from fingertip blood could identify Alzheimer's-related changes seen in cerebrospinal fluid with 86% accuracy. In addition to p-tau217, other markers such as GFAP and NfL were also successfully measured, showing high agreement with conventional tests. GFAP is a protein that changes alongside inflammatory changes or damage in the brain, and NfL is an indicator of the degree of neurofilament damage. In other words, the team confirmed the potential to read both brain change and damage signals from blood.
Notably, participants created dried blood samples by collecting their own blood without guidance from the researchers. This suggests that remote testing or large-scale studies could be possible even in areas with shortages of medical personnel or with challenges in transporting and storing specimens.
The researchers said, "It is still early for immediate clinical use and additional validation is needed. The key will be standardization, the possibility of misdiagnosis, and ensuring reproducibility across diverse populations," adding, "It could also be used for people with Down syndrome, who face higher Alzheimer's risk, and for vulnerable groups with limited access to care."
References
Nature Medicine (2026), DOI: https://doi.org/10.1038/s41591-025-04080-0