Alzheimer’s blood test up to 93% accurate

A new blood test for detecting early signs of Alzheimer’s disease was proven to be highly effective in a nearly 500-patient study.

The test was developed at Washington University School of Medicine in St. Louis and trialled on patients across three continents.

The findings provide further evidence that the test should be considered for routine screening and diagnosis in the future.

Senior author Randall J. Bateman, MD, the Charles F. and Joanne Knight Distinguished Professor of Neurology, said:

“Our study shows that the blood test provides a robust measure for detecting amyloid plaques associated with Alzheimer’s disease, even among patients not yet experiencing cognitive declines.

“A blood test for Alzheimer’s provides a huge boost for Alzheimer’s research and diagnosis, drastically cutting the time and cost of identifying patients for clinical trials and spurring the development of new treatment options.

“As new drugs become available, a blood test could determine who might benefit from treatment, including those at very early stages of the disease.”

The test assesses whether amyloid plaques have begun accumulating in the brain based on the ratio of the levels of the amyloid beta proteins Aβ42 and Aβ40 in the blood.

The current study demonstrated that the blood test is highly accurate, even when performed in different labs with different processes across three continents.

And when blood amyloid levels were combined with the presence of the genetic variant APOE4 – another major risk factor for Alzheimer’s – the accuracy of the blood test was 88 per cent compared to brain imaging and 93 per cent compared to spinal tap.

A low-cost, easily-accessible blood test would be a preferable alternative to costly brain scans, as well as spinal taps, which patients may be unwilling to endure.

The researchers estimate that a $500 test could half the cost and time in takes to enrol patients into clinical trials that use PET scans.

Screening with blood tests alone could be completed in less than six months and cut costs by tenfold or more, the research found.

Bateman said:

“These results suggest the test can be useful in identifying nonimpaired patients who may be at risk for future dementia, offering them the opportunity to get enrolled in clinical trials when early intervention has the potential to do the most good.

“A negative test result also could help doctors rule out Alzheimer’s in patients whose impairments may be related to some other health issue, disease or medication.”