A simple blood test for Alzheimer's is said to be extremely reliable
Swedish researchers demonstrate that an already available blood test can diagnose Alzheimer's with extremely high reliability. This could be groundbreaking for patient care, as many patients suspect they have this severe form of dementia due to memory loss.
According to the RKI report, approximately ten percent of Germans aged 65 and over suffer from dementia, with the risk increasing significantly with age. Alzheimer's is the most common cause of dementia, but diagnosis is complex and rarely available in primary care. Doctors must often rely solely on their experience and judgment. However, a simple blood test already on the market could change that, according to a new study from Lund University in Sweden, published in JAMA.
Research on the blood test has been ongoing since 2019. The method used measures the concentration of the biomarker plasma-phospho-tau217, a component of protein deposits in the brain tissue of affected individuals. Previous studies suggested that the blood test may be as good as, or even better than, a spinal tap (lumbar puncture).
Suitable for general practitioners
The latest Swedish study now shows for the first time that the blood test works reliably not only in the lab but also in routine care, including in general practice. "The blood test showed a reliability of about 90 percent, even in primary care," the researchers write. "This could have significant implications for those seeking help due to memory loss and suspicion of Alzheimer's."
The study involved 1213 people with mild memory problems, a possible early symptom of Alzheimer's. Of these, 515 were examined in primary care and 698 in a specialized memory clinic. A blood test was first performed, then the test results were confirmed by lumbar puncture. Additionally, specialists assessed the symptoms without knowing the test results.
"A significant advancement"
"The accuracy of general practitioners in identifying Alzheimer's disease was 61 percent, while specialists were correct in 73 percent of cases," says Sebastian Palmqvist, who led the study with Oskar Hansson. "This underscores the lack of good, cost-effective diagnostic tools, especially in primary care, and demonstrates the potential improvement in diagnosis through the introduction of this blood test in healthcare."
The test is a significant advancement in Alzheimer's diagnosis, as it offers a simple method for ruling out the disease in primary care, the researchers write. This is crucial because memory loss can also be attributed to other treatable conditions such as depression or chronic fatigue.
Close to deployment in Europe
And it offers hope. "Early diagnosis is crucial, as new treatments are being developed that can slow the progression of the disease," explains Oskar Hansson. "For example, two immunotherapies were recently approved in the US and are expected to be available in Europe soon." Early and accurate diagnosis is also important for facilitating research into new treatment options.
"The next steps involve establishing clear clinical guidelines for the use of the blood test in healthcare," says Hansson. "The test is already available in the US and will likely be offered in many other countries soon. Initially, it will primarily be used in specialized memory clinics, and it may take about one to two years for guidelines and training to be implemented in primary care."
In light of the new study, the blood test could also potentially aid in diagnosing other dementias and not just Alzheimer's, as dementia and other dementias share similar symptoms and require proper identification for appropriate treatment. The blood test's reliability in both lab and primary care settings opens up possibilities for broader diagnostic applications beyond Alzheimer's.
