Blood test diagnoses Alzheimer’s with over 90% accuracy

The detection of phosphorylated TAU 217 protein (p-tau217) in plasma has shown high precision in identifying pathological accumulations of beta-amyloid and TAU proteins. This precision is comparable to traditional biomarker detection in cerebrospinal fluid, as revealed by a recent study published in JAMA Neurology. Researchers from the Research Area in Neurological Diseases, Neuroscience, and Mental Health at the Sant Pau Research Institute, led by Dr. Juan Fortea, Director Sof the Memory Unit at the Neurology Department of the same hospital, participated in the study. These results pave the way for diagnosing Alzheimer’s disease through a blood test.

A few years ago, the only way to diagnose this neurodegenerative disease was through post-mortem brain samples. Subsequently, effective biomarkers were found for identification in cerebrospinal fluid. Now, research is focused on discovering blood biomarkers for less invasive diagnostic methods, as explained by Dr. Daniel Alcolea, researcher at the Dementia Neurobiology Group at the Sant Pau Research Institute and head of the biomarkers platform at the Memory Unit of the same hospital.

The researchers analyzed data from three observational cohorts: the Translational Biomarkers in Aging and Dementia (TRIAD) in Canada, the Wisconsin Registry for Alzheimer’s Prevention (WRAP) in the United States, and the Sant Pau Initiative on Neurodegeneration (SPIN) in Barcelona. The study involved samples from a total of 786 participants with an average age of 66.3 years, analyzed in Sweden, revealing an excellent accuracy of around 95% for detecting the presence of Alzheimer’s disease.

The results show that the p-tau217 biomarker offers precision comparable to cerebrospinal fluid biomarkers and proves to be particularly effective in detecting longitudinal changes, even in preclinical stages of the disease. An outstanding aspect of this technique is its ability to significantly reduce the need for additional confirmations, decreasing the number of tests required to confirm the diagnosis of the disease by 80%.

Dr. Alcolea explains that “this biomarker has shown very high performance in detecting Alzheimer’s in blood, with an accuracy between 90 and 95%. Of all the biomarkers currently being studied for diagnosing Alzheimer’s disease, this one has shown the best results.”

This discovery may open new avenues in the research and treatment of Alzheimer’s disease, offering an accessible and reliable tool for the medical community and patients. Dr. Alberto Lleó, researcher at the Dementia Neurobiology Group at the Sant Pau Research Institute and Director of the Neurology Department at the same hospital, explains that “this advance is particularly significant, as blood biomarkers could provide a more accessible and less invasive alternative for early diagnosis and monitoring of Alzheimer’s disease. Additionally, implementing this type of test could significantly improve clinical assessment and recruitment for clinical trials, as well as facilitate patient management and provide timely access to disease-modifying therapies.”

Reference article: Ashton NJ, Brum WS, Di Molfetta G, et al. Diagnostic Accuracy of a Plasma Phosphorylated Tau 217 Immunoassay for Alzheimer Disease Pathology. JAMA Neurol. Published online January 22, 2024. doi:10.1001/jamaneurol.2023.5319