A blood test that could detect signs of Alzheimer's disease even prior to symptom onset is in the works, and early evaluation of it has proven to be highly accurate, according to new research, published Jan. 22 in JAMA.
The test works by identifying two key biomarkers of the disease in the blood: A protein known as phosphorylated tau and also elevated levels of beta amyloid, both of which are present in the brains of patients who become diagnosed with Alzehimer's. The blood test accurately identified 96% of beta amyloid levels and found 97% of phosphorylated tau proteins in testing, according to the researchers.
"What was impressive with these results is that the blood test was just as accurate as advanced testing like cerebrospinal fluid tests and brain scans at showing Alzheimer’s disease pathology in the brain,” Nicholas Ashton, PhD, an author of the study and professor of neurochemistry at the University of Gothenburg in Sweden told CNN.
The company behind the new test, ALZpath, developed the test, which is only available for research like this study right now, but expect it to soon expand to clinical use, CNN reported. It estimates the cost for the test could range between $200-$500.
Quest Diagnostics is behind a separate, consumer-facing Alzheimer's detection blood test, AD-Detect, which tests for beta amyloid levels, but not the phosphorylated tau protein. It was approved in the last year to help patients experiencing cognitive decline measure their risk of developing Alzheimer's disease. However, doubts were also raised about its accuracy, according to CNN.
So far, in testing 786 patients' blood using the ALZpath test has shown that 80% did not need additional testing because the results were accurate and clear. Only about 20% returned results that were unclear and would require further testing mechanisms for accurate results.
Richard Isaacson, MD, director of research at the Institute for Neurodegenerative Diseases in Boca Raton, Fla., was not involved in the study, but upon reviewing the research told CNN that right now, the results are "among the best available evidence for being one single test for Alzheimer's," particularly for its ability to detect the biomarkers in blood even before symptom onset.
In the future, patients could be regularly screened using the test as a part of their clinical aging care regimens.