New Delhi: In a major breakthrough for Alzheimer’s diagnosis and treatment, scientists from Washington University School of Medicine in St. Louis and Lund University in Sweden have developed a blood test that not only detects Alzheimer’s disease but also reveals how advanced the condition is in a patient. This advancement marks a significant improvement over current blood tests, which can confirm the presence of Alzheimer’s but cannot determine the clinical stage or severity of cognitive impairment.
Published in Nature Medicine, the study highlights the development of a highly sensitive test that measures a protein fragment known as MTBR-tau243 in the bloodstream. The presence and concentration of this protein closely correlate with the buildup of tau tangles—abnormal protein clumps that are a key hallmark of Alzheimer’s disease—in the brain. Notably, the levels of MTBR-tau243 also align with the severity of dementia symptoms, offering a potential tool for staging the disease.
“This blood test clearly identifies Alzheimer’s tau tangles, which is our best biomarker measure of Alzheimer’s symptoms and dementia,” said Dr. Randall J. Bateman, Professor of Neurology at Washington University and co-senior author of the study. He emphasized the clinical significance of the findings, noting that there are currently no simple, accessible methods to assess tau tangles in the brain. This test could provide a practical alternative to invasive and expensive brain scans, while also guiding treatment decisions.
To validate the accuracy of the test, researchers analyzed data from multiple patient cohorts. Initial testing was done on 108 individuals from the U.S. and 55 from Sweden. The approach was then confirmed in a larger, independent group of 739 participants from Sweden. The results showed that blood MTBR-tau243 levels mirrored the extent of tau pathology in the brain with an impressive 92% accuracy.
Importantly, the test was also able to differentiate between patients at early and late stages of Alzheimer’s, as well as those experiencing cognitive decline due to other causes. Researchers say the test could help determine which patients might benefit most from emerging Alzheimer’s therapies, marking a step forward in personalized care.