New Blood Test to Transform Detection and Diagnosis of Alzheimer’s Disease

In the brain of patients with Alzheimer’s Disease, there is a buildup of ‘amyloid plaques’, with abnormal levels of this naturally occurring protein clumping together, disrupting cell function. Currently, amyloid plaques are detected through a lumbar puncture, an invasive procedure, while scans are limited in their availability. Blood tests offer a less invasive, more scalable, and cost-effective alternative. Now, a study has examined the effectiveness of a new blood test that could change the way Alzheimer’s Disease is identified.

In the study, researchers from Trinity College Dublin (Dublin, Ireland) investigated whether a blood test could provide a simpler and more accurate method than lumbar punctures. The blood test, known as plasma p-tau217, identifies amyloid plaques in Alzheimer’s patients. The study utilized biobank samples to compare how effectively this blood test detected amyloid proteins compared to those found in cerebrospinal fluid. The findings, published in the Alzheimer's Research and Therapy journal, showed that the blood test's accuracy was over 90% comparable to that of lumbar punctures.

The study also assessed various threshold levels for the blood test and suggested that its use could potentially eliminate over half of the lumbar punctures currently performed. This reduction could reduce the invasiveness and duration of the diagnostic process while also lowering costs. Although lumbar punctures are generally safe and well-tolerated, they can cause side effects like headaches in some patients. Future research aims to replicate these blood test results in diagnostic labs, allowing patients to initially undergo a blood test, thereby bypassing the need for a diagnostic lumbar puncture in clear-cut cases.

“This study found that blood tests such as plasma p-tau217 demonstrate excellent performance to detect the changes that are characteristic of Alzheimer’s disease,” said Dr. Adam Dyer, a Geriatric Medicine Trainee at Tallaght University Hospital and Medical Gerontology, Trinity College Dublin. “In the future, clinical use of these blood tests may enable us to avoid invasive tests such as lumbar punctures in over half of individuals who currently have these procedures performed”. This research is one of a handful in the world to assess this in ‘real-world’ clinical cohorts and the first Irish study to examine the performance of these blood tests.”

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