Breakthrough blood test could detect Alzheimer’s 20 years before symptoms manifest
Scientists may be close to a breakthrough on a blood test for Alzheimer’s disease.
Measuring for abnormal versions of a protein could signal brain changes 20 years before dementia symptoms manifest, according to new research presented Tuesday at the Alzheimer’s Association International Conference, being held online because of the coronavirus pandemic.
The blood test detects abnormal versions of the tau protein, in particular a form known as p-tau217, which seems to be the most specific to Alzheimer’s and the earliest to show measurable changes, researchers said in a statement.
With Alzheimer’s, the amyloid and tau proteins change and form clumps known as plaques and tangles, respectively, the researchers explained. While these can be detected, it takes expensive PET scan imaging or a spinal tap, the latter invasive.
“There is an urgent need for simple, inexpensive, noninvasive and easily available diagnostic tools for Alzheimer’s,” said Maria C. Carrillo, Alzheimer’s Association chief science officer, in the researchers’ statement. “The possibility of early detection and being able to intervene with a treatment before significant damage to the brain from Alzheimer’s disease would be game changing for individuals, families and our healthcare system.”
While the results are promising and indicate that researchers are on the right track, even the scientists involved in the study said the findings are preliminary.
“While these new reports are encouraging, these are early results, and we do not yet know how long it will be until these tests are available for clinical use. They need to be tested in long-term, large-scale studies, such as Alzheimer’s clinical trials,” Carrillo said in the statement. “In addition, we need to continue research to refine and verify the tests that are the current state-of-the-art — including cerebrospinal fluid and PET imaging biomarkers.”
The research was published in the Journal of the American Medical Association online Tuesday.
An earlier study measured the concentration of ptau181 in plasma, the liquid of blood that carries blood cells, the National Institutes of Health said in a release. Conducted by Adam Boxer at the University of California, San Francisco, the test could not only differentiate healthy participants from those with Alzheimer’s pathology but could also “differentiate those with Alzheimer’s pathology from a group of rare neurodegenerative diseases known collectively as frontotemporal lobar degeneration (FTLD),” the NIH said.
That research was published in Nature Medicine on March 2.
In this latest research, the p-tau217 test outperformed numerous other measures for indicating which patients had Alzheimer’s as verified by brain scans and was comparable in accuracy to brain scans and some spinal tests, the researchers said.
Among the subjects were 81 people in Arizona who had donated their brains at death, so researchers were able to compare blood test results to the brains posthumously, the Associated Press reported.
If results continue to pan out, a clinical test could be available in about two years, Carillo said, according to AP.
“When patients come to me with changes in their memory and thinking, one of the major questions is, what’s the cause? Is it Alzheimer’s disease or is it something else?” Dr. Suzanne Schindler of Washington University in St. Louis told AP. If tau testing bears out, “it would help us diagnose people earlier and more accurately.”
With News Wire Services.
