A new blood test could diagnose Alzheimer’s Disease 20 years before symptoms appear, paving the way for breakthroughs in research and treatment.

It’s hoped the blood test could ultimately lead to improvements in the diagnosis, potential prevention and treatment of Alzheimer’s Disease.

Longevity.Technology: Alzheimer’s Disease can only be definitively diagnosed after death. However, a team of researchers has made a significant breakthrough by developing a new blood test which could detect changes in the brain two decades before any dementia symptoms occur.

Given that Alzheimer’s affects around 50 million people worldwide and that the general population aged 60 and over with dementia at any given time is between five and eight per cent [1], it’s clear that any breakthrough in the diagnosis and treatment of this disease could have a considerable impact on an aging population. 

According to a large-scale international study, which has been published in the Journal of the American Medical Association [2], a new test has shown significant potential in being able to detect whether a patient has Alzheimer’s or not. In people who have a known genetic risk, the test may be able to detect Alzheimer’s as early as 20 years before any demonstrable cognitive impairment occurs. 

Oskar Hansson, MD, PhD, Professor of Clinical Memory Research at Lund University, Sweden, who leads the Swedish BioFINDER Study and spearheaded the latest international collaboration, said: “While more work is needed to optimize the assay and test it in other people before it becomes available in the clinic, the blood test might become especially useful to improve the recognition, diagnosis, and care of people in the primary care setting.”

Up until now, Alzheimer’s diagnosis has typically been definitively made after death, based upon the characterization of aggregates of protein known as amyloid plaques and abnormal accumulations of protein or tau tangles in the brain. 

… the test was able to discriminate with 89% accuracy between brain donors with and without a neuropathological diagnosis of an intermediate or high likelihood of Alzheimer’s.

Therefore, the successful development of an inexpensive, and widely available, blood test to determine whether such plaques and tangles are present could have a momentous impact on Alzheimer’s research and care. 

The new research has found that measurements of the phospho-tau217 protein could provide an accurate indication of whether plaques and tangles are present in order to diagnose Alzheimer’s in living patients rather than at postmortem. Study authors are confident that the p-tau217 blood test has demonstrated considerable promise in the diagnosis, early detection and study of Alzheimer’s.

Researchers, who were coordinated from a central hub at Lund University in Sweden, evaluated the efficacy of the blood test in 1,402 cognitively impaired and unimpaired research participants from respected studies in Sweden, Arizona and Colombia. 

In the Arizona research, the test was able to discriminate with 89% accuracy between brain donors with and without a neuropathological diagnosis of an intermediate or high likelihood of Alzheimer’s and between those with and without a diagnosis of a high likelihood of Alzheimer’s with a 98% accuracy. In Sweden, the accuracy was between 93% and 96% and, in the Colombia Cohort, the assay was able to distinguish between mutation carriers and non-carriers two decades before participants would be likely to see the start of mild cognitive impairment. 

Having the ability to accurately test for Alzheimer’s before cognitive impairment occurs could be key to future treatment, and timing of such treatment. This latest study adds to an extensive body of research into the diagnosis, treatment, and potentially, ultimate cure for Alzheimer’s. For instance, research in New York has discovered that triggering immune cells could slow brain aging, while a number of research teams including scientists at Tufts University are looking into how to deliver Alzheimer’s treatment across the blood brain barrier (BBB).

Eric Reiman, MD, Executive Director of Banner Alzheimer’s Institute in Phoenix and a senior author on the study, said: “Blood tests like p-tau217 have the potential to revolutionize Alzheimer’s research, treatment and prevention trials, and clinical care. While there’s more work to do, I anticipate that their impact in both the research and clinical setting will become readily apparent within the next two years.” 

[1] https://www.who.int/news-room/fact-sheets/detail/dementia
[2] https://www.eurekalert.org/pub_releases/2020-07/lu-nbt072820.php
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