blood test Alzheimer's
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A new blood test shows promise in detecting Alzheimer’s as early as 20 years before the onset of cognitive impairment, according to researchers

For years, the diagnosis of Alzheimer’s has been based on the characterisation of amyloid plaques and tau tangles in the brain, typically after a person dies. However, a study in published in the Journal of the American Medical Association (JAMA) has found that an inexpensive and widely available blood test, for the presence of plaques and tangles, would have a profound impact on Alzheimer’s research and care.

Alzheimer’s is an incurable disease that currently effects around 5.8 million Americans over the age of 65. Without the discovery of successful prevention, cases in the U.S. could reach nearly 14 million by 2050.

According to the new study, measurements of phospho-tau217 (p-tau217), one of the tau proteins found in tangles, could be an accurate indicator of both plaques and tangles, corresponding to the diagnosis of Alzheimer’s, in living people.

The blood test could be undertaken on those persons at known genetic risk of Alzheimer’s.

Oskar Hansson, Professor of Clinical Memory Research at Lund University, who leads the Swedish BioFINDER Study said: “The p-tau217 blood test has great promise in the diagnosis, early detection, and study of Alzheimer’s.

“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.”

Promise in the p-tau217 blood test

Researchers evaluated the new p-tau217 blood test in 1,402 cognitively impaired and unimpaired research participants from well-known studies in Arizona, Sweden, and Colombia. The study, which was coordinated from Lund University in Sweden, included 81 participants from Arizona who underwent clinical assessments and provided blood samples in their last years of life. They then had neuropathological assessments after they died.

The study findings showed that p-tau217 blood test accurately identified Alzheimer’s from other neurodegenerative diseases in both the Arizona-based neuropathology cohort and the Swedish BioFINDER-2 study. In the third Colombian cohort, p-tau217 in mutation carriers’ blood was elevated around 20 years before their estimated age at the onset of mild cognitive impairment.

In each of these analyses, p-tau217 outperformed p-tau181 (another component of tau tangles and a blood test recently found to have promise in the diagnosis of Alzheimer’s) and several other studied blood tests.

Study leaders include Jeffrey Dage, from Eli Lilly and Company, who developed the p-tau217 assay, Sebastian Palmqvist, and Shorena Janelidz, from Lund University, and Eric Reiman, from Banner Alzheimer’s Institute.

Although more work is needed before the test can be clinically available, the p-tau217 blood test has the potential to provide information about both plaques and tangles, corresponding to the diagnosis of Alzheimer’s.

Eric Reiman, a senior author on the study, commented: “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.”

The study can be found here.


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