A groundbreaking study from Washington University School of Medicine in St. Louis and Lund University in Sweden has introduced a new blood test that not only helps diagnose Alzheimer’s disease, but also determines how far the disease has progressed—a vital step toward personalized care for patients.
Published in Nature Medicine, the study highlights the potential of a protein called MTBR-tau243, found in blood, to reflect the amount of tau tangles in the brain.
Tau tangles, along with amyloid plaques, are a key hallmark of Alzheimer’s and are closely linked to the development of memory loss and cognitive decline.
This new test marks a major advancement over current blood-based Alzheimer’s diagnostics, which primarily detect amyloid buildup but fall short of indicating the clinical stage of the disease.
Knowing how advanced the disease is can help doctors decide which treatments are appropriate and when to start them—especially as new therapies emerge that are more effective in specific stages.
The researchers analyzed blood samples from nearly 900 people across different stages of Alzheimer’s disease—from individuals with no symptoms but amyloid buildup, to those with mild cognitive impairment and others with full-blown dementia.
They compared MTBR-tau243 levels in the blood to brain scan results measuring tau tangles, and found a 92% accuracy rate in detecting and staging Alzheimer’s.
Low MTBR-tau243 levels were found in healthy individuals, even those with early amyloid plaques.
Moderate levels were seen in people with early symptoms.
Extremely high levels—up to 200 times higher—were found in individuals with Alzheimer’s dementia.
Importantly, people whose symptoms were due to other conditions had normal MTBR-tau243 levels, helping distinguish Alzheimer’s from other causes of memory loss.
Currently, staging Alzheimer’s requires PET brain scans, which are expensive, invasive, and often unavailable outside large hospitals or research centers. In contrast, a simple blood test is fast, less costly, and widely accessible, making early and accurate staging of Alzheimer’s disease feasible in regular clinical settings.
Dr. Randall Bateman, co-senior author of the study, emphasized the impact:
“This tangle blood test provides a much better indication if symptoms are due to Alzheimer’s and helps guide which treatments are most suitable.”
A Tool for Personalized Medicine
Alzheimer’s treatment is entering a new era. The FDA has approved two drugs that slow Alzheimer’s by targeting amyloid, but these are most effective in early stages. More therapies—especially ones that target tau—are in development.
Dr. Kanta Horie, co-first author, noted that the availability of accurate staging tools like this test would allow doctors to tailor treatment strategies:
“For patients with low tau tangle levels, anti-amyloid therapies may work best. For those with high tau, anti-tau or other treatments may be more effective.”
While p-tau217 blood tests are already being used to diagnose Alzheimer’s, MTBR-tau243 adds a new layer by offering disease staging. Used together, these biomarkers could significantly boost diagnostic precision.
As co-senior author Dr. Oskar Hansson explained:
“When both p-tau217 and MTBR-tau243 are positive, the chances that Alzheimer’s is the cause of symptoms increase dramatically.”
The MTBR-tau243 test is currently under development by C2N Diagnostics, a startup spun out of Washington University that also developed earlier blood tests for amyloid. As more experimental drugs targeting tau or other mechanisms move closer to approval, the ability to match treatments to disease stage using a blood sample could transform Alzheimer’s care.
In conclusion, this new blood test represents a significant advance in the diagnosis and management of Alzheimer’s disease. It offers a fast, non-invasive, and accurate way to not only confirm Alzheimer’s, but also determine how advanced it is—laying the groundwork for personalized, stage-specific treatments that can dramatically improve patient outcomes.
If you care about dementia, please read studies about dietary strategies to ward off dementia, and how omega-3 fatty acids fuel your mind.
For more health information, please see recent studies about Choline deficiency linked to Alzheimer’s disease, and what to eat (and avoid) for dementia prevention.
The research findings can be found in Nature Medicine.
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