A study shows the effectiveness of a new blood test-based test for detecting one of the most common neurodegenerative diseases
As the world's population ages, health experts expect an increase in age-related diseases, including Alzheimer's. Finding new ways to diagnose the disease is a higher priority than ever because new treatments work best in the earliest stages of the disease.
However, currently the two main methods of diagnosing Alzheimer's disease (PET scan or lumbar puncture) are too expensive or invasive, leaving too many cases undiagnosed.
In a study published in JAMA Neurology, researchers report a promising, more accessible test that uses blood and could enable more comprehensive screening and monitoring of this neurodegenerative disease. Researchers at the University of Gothenburg, Sweden, worked with ALZPath, a company that has developed a blood-based Alzheimer's test for research studies, to determine how well the test compares to current tests. Reference of PET and cerebrospinal fluid (CSF) images obtained through lumbar punctures. Researchers analyzed scans, or cerebrospinal fluid and blood samples, from nearly 800 people from three different patient populations in the United States, Canada and Spain.
In comparison, the blood test worked as well as the CSF test in detecting Alzheimer's, which is an encouraging result since the CSF test works as well as PET scans in diagnosing the disease. “This test showed that blood and cerebrospinal fluid worked in exactly the same way,” says Nicholas Ashton, associate professor of neurochemistry at the University of Gothenburg and lead author of the study. “The blood test worked great – it was almost 95% accurate – and in that sense it could end up replacing CSF.”
As effective as a lumbar puncture
The test measures a substance called phosphorylated tau, a protein that has been shown to be a strong indicator of Alzheimer's disease. Levels of phosphorylated tau tend to rise when clumps of amyloid protein, the hallmark of Alzheimer's, begin to form in the brain, often years before symptoms of memory loss and cognitive decline appear. The blood test uses proprietary technology that makes it highly sensitive to even small amounts of protein, which could make it a useful tool in detecting the disease.
According to Ashton, Swedish doctors are beginning to incorporate blood tests into a comprehensive Alzheimer's diagnosis and treatment program. They start by conducting a real-world study and collecting blood samples to determine what proportion of patients could be reliably diagnosed with the blood test alone, for example, and which may require additional confirmatory tests such as CSF. “We hope that all people suspected of having dementia will have access to this test, which will reveal the underlying pathology that could be causing their symptoms,” says Ashton.
If you have Alzheimer's, the blood test could also identify patients who might benefit from new anti-amyloid treatments like lecanemab and help doctors monitor your response to the drug.
The ALZPath test is currently only available to scientists for purchase for research studies through select partner laboratories, but is expected to be available for use in patients within a few months.
REFERENCE
Diagnostic accuracy of a plasma phosphorylated Tau 217 immunoassay for Alzheimer's disease pathology