Several blood tests have been shown to accurately diagnose Alzheimer’s disease — as previously reported by Fox News Digital — but now a new test has emerged that can gauge how far it has progressed.
The study, which was published Monday in Nature Medicine journal, was led by researchers at Washington University School of Medicine in St. Louis and Lund University in Sweden.
Determining the clinical stage of dementia can help ensure that the patient receives the most beneficial treatment, according to researchers.
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The new test could also help confirm whether Alzheimer’s or another condition is causing a person’s symptoms.
The researchers analyzed blood samples for 163 people who were experiencing various levels of cognitive decline, from presymptomatic to early-stage to late-stage dementia.
They found that levels of a protein called MTBR-tau243 correlate to the amount of tau that has accumulated in the brain, according to a WashU press release. Accuracy compared to brain scans was 92%.
Levels of MTBR-tau243 were normal in people who did not yet have symptoms, which indicates that the protein is associated with more advanced stages.
Levels were also normal for people whose symptoms were linked to another cause other than Alzheimer’s.
Tau is a protein that clumps together and forms “tangles” in the brains of people who have Alzheimer’s, per Healthline. These tangles interfere with cognitive function.
Tau tangles typically form years after the formation of another protein called amyloid, which creates plaques in the brain and is one of the first hallmarks of Alzheimer’s.
The greater the amount of tau accumulation, the more severe the Alzheimer’s symptoms — it was 200 times higher for those in later dementia stages, the study found.
“Amyloid plaques and tau tangles together define the basic biological brain changes of Alzheimer’s disease, along with the loss of brain cells and synapses,” Courtney Kloske, Ph.D., director of scientific engagement at the Alzheimer’s Association in Chicago, told Fox News Digital. “These changes cause the well-known memory and thinking symptoms of dementia.”
While previously developed blood tests measure levels of amyloid plaques in the brain, this is the first one to measure tau levels.
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“To aid in early detection, we have seen advances in blood tests for amyloid, which have been shown to be highly accurate and are now available to aid clinicians in their diagnostic workup,” said Kloske.
“The current study is looking at the accuracy of a blood test for tau; once these blood tests are developed, confirmed and validated, positive results on both tests would strongly confirm Alzheimer’s disease as the cause of the person’s dementia. This makes for a more confident and definitive diagnosis and clarifies options for treatment.”
Co-senior author Randall J. Bateman, MD, the Charles F. and Joanne Knight Distinguished Professor of Neurology at WashU Medicine, noted that in clinical practice today, there is not an easy or accessible measure of Alzheimer’s tangles and dementia.
“This blood test clearly identifies Alzheimer’s tau tangles, which is our best biomarker measure of Alzheimer’s symptoms and dementia,” he said in the release.
“A tangle blood test like this can provide a much better indication if the symptoms are due to Alzheimer’s, and may also help doctors decide which treatments are best for their patients.”
The hope is that this new blood test could make it easier to stage Alzheimer’s patients and tailor treatments to their individual needs.
PET (positron emission tomography) brain scans are now the standard for staging, but they have some drawbacks, the researchers noted.
They are “expensive, time-consuming and frequently unavailable outside of major research centers,” which limits their use.
“We’re about to enter the era of personalized medicine for Alzheimer’s disease,” said co-first authors Kanta Horie, PhD, a research associate professor of neurology at WashU Medicine, in the release.
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“For early stages with low tau tangles, anti-amyloid therapies could be more efficacious than in late stages. But after the onset of dementia with high tau tangles, anti-tau therapy or one of the many other experimental approaches may be more effective,” he went on.
“Once we have a clinically available blood test for staging, plus treatments that work at different stages of the disease, doctors will be able to optimize their treatment plans for the specific needs of each patient.”
Kloske echoed the need for further research.
“While this research is promising for more early detection methods, we need to see the replication and expansion of these results in larger and more representative study populations to understand the implications in the general population,” she told Fox News Digital.
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The study was funded by the Charles F. and Joanne Knight Alzheimer Disease Research Center, the Tracy Family SILQ Center, the National Institutes of Health (NIH), the Alzheimer’s Association’s Zenith Award, the Hope Center for Neurological Disorders and the Department of Neurology at WashU Medicine.
