WASHINGTON - A simple blood test that can detect Alzheimer’s disease years before symptoms appear may be one step closer to reality.

The latest test focuses on amyloid beta proteins that have misfolded and are starting to clump together in the brain, a hallmark of Alzheimer’s disease.

At one time, they could be found only during an autopsy. Now, they are often uncovered with advanced imaging tests. 

The test was developed by researchers at the University of Washington, and their findings were published in the Proceedings Of The National Academy Of Sciences on Monday.  

Finding patients earlier in the course of their disease will give them time to prepare and make changes that could help them later, said University of Washington professor of bioengineering Valerie Daggett, senior author of the study.

A spate of positive news from companies including Eisai Co and rival Eli Lilly & Co has renewed hope that effective treatments may be found to slow the mental decline.

“For early treatment, we first need early diagnosis,” Prof Daggett said. “Also, with an early diagnosis, there are lifestyle modifications that can prove helpful and buy time for other therapeutics to come on the market.”

The new approach involves measuring levels of what is known as toxic oligomers, a build-up of those misfolded proteins that over time are believed to contribute to Alzheimer’s disease.

The study involved blood donated years earlier by 310 people.

Out of 53 people verified after death to have had Alzheimer’s disease, 52 had signs of the toxic oligomers on average six years earlier. 

More significantly, they were also present in 11 people who seemingly had no memory problems or signs of dementia when they gave the blood. 

Follow-up records were available for 10 of those volunteers, and all were subsequently diagnosed with symptoms consistent with Alzheimer’s disease.

Of the 220 people without the toxic oligomers in their blood, two were subsequently found to have signs of the disease.

The tests currently in commercial use are limited to diagnosing people who already have symptoms.

For example, Fujirebio Diagnostics’ Lumipulse G ß-Amyloid Ratio test – which was approved by the US Food and Drug Administration in May – is a lab-based test intended for adults aged 55 years and older with cognitive decline.

Scientists have previously touted blood tests for predicting the disease, with Shimadzu and Roche among firms that have looked into the method in the past.

Most tests remain in the trial stage.

C2N Diagnostics, which has a commercially available blood test to detect amyloid, announced last week that it will launch another version in the first quarter of next year that will look for amyloid and the tau protein that has also been linked to the disease. 

AltPep Corp, a spin-off from Prof Daggett’s lab, is developing the diagnostic that has received breakthrough status from the US Food and Drug Administration.

It is also working on a drug to neutralise oligomers.

The researchers say the test does not require sophisticated equipment and does not need to take into account things such as age and other risk factors.

That would potentially make it easy to use in standard labs and clinics, Prof Daggett said, though it is hard to know when it might be available.

“We don’t know the cost yet, but our goal is an affordable test that can be deployed on a global scale,” she said.  BLOOMBERG