A groundbreaking study from Lund University in Sweden has revealed that a new blood test can diagnose Alzheimer's disease with over 90% accuracy, marking a significant advance in the early detection and treatment of this debilitating condition. Published in the Journal of the American Medical Association, the research suggests that this test could revolutionize how Alzheimer's is diagnosed, providing a more accessible and efficient alternative to current methods.
The study focuses on the p-tau217 blood test, which measures the levels of a specific peptide associated with neurological damage caused by Alzheimer's. The test demonstrated a 91% accuracy rate in diagnosing Alzheimer's-related memory loss, compared to the 73% accuracy of specialist doctors and the 61% accuracy of primary care physicians. This allows for a more precise differentiation between Alzheimer's and other forms of dementia.
The findings emphasize the potential impact of this test on clinical care, especially in regions with limited access to advanced diagnostic technologies. "An accurate, biomarker-verified Alzheimer disease diagnosis can have a positive effect on clinical care and prognostication," the study states. Current gold-standard methods such as spinal taps and brain imaging are costly, less accessible, and often involve long waiting periods. The new blood test offers a simpler, more efficient diagnostic tool.
The research involved approximately 1,200 participants with an average age of 74 who were undergoing evaluations for possible Alzheimer's. The blood test results were compared to diagnoses made by doctors and spinal tap tests, with the blood test proving significantly more accurate.
Dr. Jason Karlawish, co-director of the Penn Memory Center at the University of Pennsylvania, lauded the study's outcomes. "Not too long ago, measuring pathology in the brain of a living human was considered just impossible," he told The New York Times. "This study adds to the revolution that has occurred in our ability to measure what's going on in the brain of living humans."
Alzheimer's is believed to be linked to the abnormal accumulation of proteins such as amyloid and tau in and around brain cells. Amyloid proteins form plaques in the brain, while tau proteins form tangles, leading to neuron death and impaired brain function. The blood test measures a form of tau that correlates with plaque buildup, making it a reliable indicator of Alzheimer's disease.
Dr. Suzanne Schindler, a neurologist at Washington University in St. Louis, explained, "A high level of this protein strongly indicates Alzheimer's, while a low level suggests other causes of memory loss."
According to the Centers for Disease Control and Prevention (CDC), Alzheimer's is the most common form of dementia, affecting up to 5.8 million Americans in 2020. With the aging population, this number is expected to rise significantly. Early and accurate diagnosis is crucial for effective management and treatment of the disease.
The Alzheimer's Association is currently developing guidelines for the use of blood tests in diagnosis, and several companies are planning to seek FDA approval for these tests. Experts advise that blood testing should initially be limited to use by doctors and researchers, with public availability restricted to those participating in research studies.
The development of accurate diagnostic tools is particularly important given the limitations of existing treatments. New drugs like donanemab and Leqembi have shown promise in slowing the progression of Alzheimer's but come with significant side effects, including brain swelling and bleeding. These medications target amyloid buildup, but their long-term efficacy and safety are still under evaluation.
Dr. Maria Carrillo, the Alzheimer's Association's chief science officer, stressed the necessity for reliable blood tests. "They should only use blood tests proven to have a greater than 90% accuracy rate," she stated.
