July 20, 2023 – A finger-prick blood test can accurately discover key biomarkers of Alzheimer's disease without the necessity for temperature or storage control measures, results from a brand new study suggest.
Using blood samples to detect amyloid and other markers of Alzheimer's disease has turn out to be standard practice in monitoring patients in clinical trials, but this presents a logistical challenge since it requires rigorous, time-limited and temperature-dependent protocols.
To make this process more efficient, the researchers conducted a pilot study investigating a brand new approach to detection. It involves dropping a small sample of blood onto a blood sample card, where it dries and stays at room temperature.
To examine the accuracy of the test, researchers recruited 77 volunteers who attended a memory clinic in Barcelona. Whole blood samples were collected using conventional needles and syringes, in addition to by finger prick, just like a diabetes blood test.
In a subgroup of 28 patients, researchers also took samples of cerebrospinal fluid, which is present in the tissue that surrounds the brain and spinal cord and is the “absolute gold standard of AD diagnosis,” said study co-investigator Dr. Nicholas Ashton, an associate professor on the Department of Neuroscience and Physiology on the University of Gothenburg in Sweden.
The blood samples were shipped overnight without temperature control or refrigeration to Gothenburg, where they were extracted from the blood sample cards and tested for the presence of Alzheimer's biomarkers.
The results showed an “extremely good relationship” between information from blood obtained using the conventional method and that from a single finger prick.
The results were presented on the Alzheimer's Association International Conference (AAIC) 2023.
“We say we can measure established markers for AD with a single finger prick. That means you don't have to centrifuge or freeze the sample. It can be done anywhere,” Ashton said.
If the test is validated in larger studies, it could mean that patients with memory complaints might be tested remotely in the longer term by taking a typical memory test online and sending a blood sample card by mail.
Not only could this facilitate earlier diagnosis, nevertheless it may be used to repeatedly monitor the consequences of treatment. Ashton said this is very necessary now that disease-modifying drugs have gotten available.
“If you're on one of these treatments, you can send tests to a lab to see how you're doing with the medication,” he said. “It's not just a blanket 6-month checkup when you're on a medication; it can be done weekly and tailored to the person taking the medication.”
The study shows that the samples remained stable at room temperature for as much as a month, which is “really encouraging,” although there are still some challenges with unsupervised blood collection, Ashton said.
Current, necessary research
Percy Griffin, PhD, chief scientific officer of the Alzheimer's Association, commented on the research: The indisputable fact that the study showed that blood samples obtained from fingerprints might be dried and shipped overnight without temperature control could lead on to earlier and more accurate diagnoses in areas with relatively few resources. In addition, this kind of test could allow for easier monitoring of high-risk patients during therapy, he said.
However, he identified that this was a pilot study and the outcomes would need to be reproduced.
The blood tests were more reliable in diagnosing Alzheimer's than results from primary care doctors, so these results are necessary. Inaccuracies “all too often lead to uncertainty and potentially inappropriate treatment,” Griffin said.
“This again demonstrates the great potential of blood tests to improve diagnostic accuracy and appropriate treatment.”