Scientists at Ruhr-Universität Bochum (RUB) in Germany have developed a blood test that could help identify Alzheimer’s disease nearly eight years before the initial clinical symptoms appear.
Existing techniques detect the disease only after the formation of plaques in the brain, a stage when therapy is not effective.
Based on the information that first protein level changes by Alzheimer’s occur up to 20 years sooner, the German team developed a two-tier approach to detect the neurodegenerative disease in the blood at an early stage.
In 2016, the researchers developed a blood test that could identify the amyloid beta protein misfolding.
Even though the test was able to diagnose the disease in symptomless stages in 71% of the cases, it was considered unsuitable for clinical application because of its false positive diagnoses for 9% of the subjects.
To reduce the false positives, the new approach employs the original blood test to identify high-risk individuals followed by an additional test for tau protein, a dementia-specific biomarker.
People who test positive in the first step are subjected to the second test conducted using cerebrospinal fluid from spinal cord, and those testing positive for both biomarkers are considered at high risk for developing Alzheimer’s.
In a study, the two-tier approach was able to correctly identify 87 out of 100 patients, with false positives in healthy subjects being three of 100.
The researchers believe that the new test offers hope for early-stage therapies.
RUB biophysics department professor Klaus Gerwert said: “Now, new clinical studies with test participants in very early stages of the disease can be launched.
“Recently, two major promising studies have failed, especially crenezumab and aducanumab – not least because it had probably already been too late by the time therapy was taken up. The new test opens up a new therapy window.”
The test has been devised as a fully automated sensor and further research is being conducted to better detect the tau protein.
This research has been published in the Alzheimer’s and Dementia: Diagnosis, Assessment and Disease Monitoring journal.