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A new type of blood test can detect a hidden toxin that underlies Alzheimer's disease years before a patient shows any symptoms of memory loss or confusion, Science Alert reported.



If the proof of concept can be further tested and expanded, the test could significantly speed up diagnosis, giving millions of patients answers and access to appropriate care long before the disease develops.



Researchers at the University of Washington (UW) created the new blood test.

It was developed to detect a molecular precursor in the blood that can cause proteins to misfold and clump in the brain, eventually forming amyloid beta (Aβ) plaques.

Aβ plaques are a known hallmark of Alzheimer's disease, but their role in cognitive decline is unclear.

In the past, these extracellular plaques were considered an early trigger of neuronal dysfunction and loss, ultimately leading to cognitive decline.

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However, recent studies show that Aβ plaques are present in only one third of patients with Alzheimer's disease, and sometimes they are also present in the brains of people who do not experience cognitive deficits.


In other words, extracellular Aβ plaques in the brain are not necessarily toxic per se, but they may originate from notoriously difficult-to-detect molecular toxins.



Scientists are still working out the details, but the hypothesis has led UW researchers to come up with an impressively accurate soluble oligomer binding test called SOBA.

The researchers first tested SOBA on the blood plasma of 310 participants.

Some of the participants showed mild cognitive impairment or Alzheimer's disease, while others were in good cognitive health.



By measuring toxic Aβ oligomers in blood plasma, SOBA detected all 53 participants with Alzheimer's who were later confirmed to have the disease after death.



Meanwhile, in the control group, SOBA detected oligomers in the blood plasma samples of 11 people.

Ten of these participants were later diagnosed with mild cognitive impairment or Alzheimer's disease.

"What the researchers wanted was a reliable diagnostic test for Alzheimer's disease—and not just a test that confirmed a diagnosis of Alzheimer's, but one that could detect signs of the disease before cognitive impairment occurs," says bioengineer Valerie Daggett. from UW, Nova TV reported.

"This is important for human health and for all research into how toxic amyloid beta oligomers continue to cause damage. What we show here is that SOBA can be the basis of such a test."