Race to detect Alzheimer’s accelerates with blood test

The latest test focuses on amyloid beta proteins that have misfolded and begin to clump together in the brain, a hallmark of Alzheimer’s disease. Previously they could only be detected during an autopsy. Now they are usually discovered with advanced imaging tests.

According to Valerie Daggett, the study’s lead author and a professor of bioengineering at the University of Washington, if it is discovered in patients earlier in the disease, they will have time to prepare and make changes that could help them later. A spate of positive news from companies including Eisai Co. and rival Eli Lilly & Co. has renewed hope of finding effective treatments to slow mental decline.

“For early treatment, we first need early diagnosis,” he said in an interview. “In addition, with early diagnosis there are lifestyle modifications that can be helpful and buy time for other therapies to come to market,” she added.

toxic proteins

The new approach involves measuring levels of what are known as toxic oligomers, a buildup of misfolded proteins that, over time, are thought to contribute to Alzheimer’s disease. The study used blood donated years before by 310 people. Of the 53 people whose Alzheimer’s disease was found after death, 52 had signs of the toxic oligomers an average of six years earlier.

More significantly, they were also present in 11 people who apparently had no memory problems or signs of dementia when they donated their blood.

According to the report published in the Proceedings of the National Academy of Sciences, follow-up records were available for 10 of these volunteers, and all were later diagnosed with symptoms consistent with Alzheimer’s disease. Of the 220 people without toxic oligomers in their blood, two later developed signs of the disease.

Tests currently in commercial use are limited to diagnosing people who already have symptoms. For example, Fujirebio Diagnostics Inc.’s Lumipulse G ß-Amyloid Ratio test, which was approved by the US Food and Drug Administration in May, is a laboratory test intended for adults 55 and older with cognitive impairment.

Scientists have previously touted blood tests for predicting disease, with Japan’s Shimadzu Corp. and Roche Holding AG among companies that have investigated the method in the past. Most remain in the testing phase.

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