Finger prick test for Alzheimer's disease?

A finger prick blood test can accurately identify the important biomarker p-tau217. alzheimer's disease (AD) — No need for temperature or storage management.

In a pilot study, researchers found a good correlation between p-tau217 levels in blood obtained by standard venous sampling and a single finger prick.

“Capillary p-tau217 from dried blood spots has limitations of standard venous sampling, which is invasive, relies on centrifuges and ultra-low temperature freezers, and requires smaller volumes than standard plasma analysis. We believe that it is possible to overcome this problem,” said the lead researcher. Dr. Hanna Huber, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, University of Gothenburg, Sweden.

The study results were presented at the 17th Clinical Trials in Alzheimer's Disease (CTAD) conference on October 30th.

Strong connection between venous and capillary samples

p-tau217 has emerged as the most effective blood test for identifying AD. However, traditional venous blood sampling requires specific infrastructure and immediate processing. Increasing and simplifying access to this blood biomarker could be important for early diagnosis, appropriate patient management, and rapid initiation of disease-modifying treatments.

The DROP-AD project is investigating the diagnostic performance of fingerstick sampling to accurately measure p-tau217.

For the study, the researchers collected paired venous and capillary blood samples from 206 adults with and without cognitive impairment (mean age 71.8 years, 59% female) from five European centers. Some participants provided a second fingerstick sample, which was taken without any supervision.

Capillary blood samples were collected with a single finger prick, and a drop of blood was then applied to a dried plasma spot (DPS) card and transported to the laboratory (without temperature control or cooling) for p-tau217 measurement. It was done. Cerebrospinal fluid biomarkers were available in some individuals.

Across the study population, there was a “very convincing correlation” between capillary DPS and p-tau217 levels from venous plasma, Huber told conference attendees.

Furthermore, capillary DPS p-tau217 levels could distinguish between amyloid-positive and amyloid-negative individuals, and levels of this biomarker increased stepwise from those without cognitive impairment to those with cognitive impairment. ” mild cognitive impairment And finally, for dementia patients. '' Huber said.

Of note, capillary p-tau217 levels in DPS samples collected by research staff did not differ from unsupervised self-collected samples.

What about sample stability? Capillary DPS p-tau-217 is “stable for more than two weeks at room temperature,” says Huber.

Are you ready for prime time?

Preliminary data from the DROP-AD project highlight the potential of using fingerstick blood sampling to identify two other AD biomarkers, neurofilament rays (NfL) and glial fibrillary acidic protein (GFAP). Masu.

“If the results are confirmed in longitudinal and home-based sampling cohorts, capillary P-TAU217 as well as other biomarkers will become a widely available and inexpensive alternative for clinical practice and clinical trials in individuals with cognitive decline.” We believe this could be the case,” Huber concluded.

“Being able to measure biomarkers with a simple finger prick could facilitate regular and autonomous sampling at home, which would be particularly useful in remote and rural settings,” she noted. .

The results of this study confirm and extend the research team's previous findings. reported last year At the Alzheimer's Association International Conference (AAIC).

“The data shared at CTAD 2024 and related materials previously presented at AAIC 2023 report on a ‘finger prick’ blood testing approach, which is interesting new research but not yet ready for clinical use. '' said Alzheimer's Association Vice President for Scientific Engagement. Medscape Medical News.

“However, the idea of ​​a highly accessible and scalable tool that can support easier and more equitable diagnosis is welcomed by researchers, clinicians, individuals and families affected by Alzheimer's disease and all other dementias.” “It will be done,” Edelmayer said.

“This finger-stick blood testing technology for Alzheimer's disease biomarkers needs to be further broadly validated, but is very promising. Advances in technology and practice have shown that the use of blood-based biomarkers for Alzheimer's disease is very promising. It has proven its simplicity, transportability and diagnostic value,” she added.

The Alzheimer's Association is currently conducting a systematic review of the evidence and developing clinical practice guidelines for blood-based biomarker testing for specialized healthcare settings, with publications, clinical resources, and tools expected in 2025. Edelmayer said.

This study received no commercial funding. Huber and Edelmayer report no relevant conflicts of interest.