Blood test highly accurate at spotting early brain changes of Alzheimer’s

Based on new findings by researchers at Washington University School of Medicine, a blood test capable of identifying brain changes of Alzheimer’s disease with high accuracy before symptoms emerge might soon be put to clinical use.

According to the study, released in the journal Neurology, researchers were able to measure blood levels of amyloid-beta, a protein associated with the neurodegenerative disease, with a 94 percent accuracy to predict whether the protein had build-up in the brain. The study may lead researchers to faster screening in patients, potentially more efficient than the conventional method by PET scans. The findings could also aid in the development of new treatments through clinical trials.

“Right now we screen people for clinical trials with brain scans, which is time-consuming and expensive, and enrolling participants takes years,” said Dr. Randall Bateman, senior author of the study. “But with a blood test, we could potentially screen thousands of people a month. That means we can more efficiently enroll participants in clinical trials, which will help us find treatments faster, and could have an enormous impact on the cost of the disease as well as the human suffering that goes with it.”

Using mass spectrometry, a technique tested in previous studies, researchers measured the quantity of two forms of amyloid-beta in the blood: amyloid-beta 42 and amyloid-beta 40, in 158 adult participants over the age of 50. 10 of the participants were classified as cognitively healthy. All the participants underwent at least one blood test and PET scan, with each blood sample and PET scan receiving a classification of either amyloid positive or negative.

Upon examination, each participant’s blood test was in accordance with their PET scan 88 percent of the time. However, to strengthen the test’s accuracy, researchers took things a step further and included major risk factors associated with Alzheimer’s, such as age and a genetic variant known as APOE4. The inclusion of these two risk factors improved the accuracy of the blood test by 94 percent, the findings showed.

In another part of the study, researchers reaffirmed the significance of blood tests in improving prescreening of Alzheimer’s. The team probed an Alzheimer’s prevention trial called the A4 study, which utilized PET scans to identify early brain changes among participants. This study concluded blood testing after PET scanning could have decreased the number of PET scans by two thirds and saved a drastic amount of monetary loss.

“Reducing the number of PET scans could enable us to conduct twice as many clinical trials for the same amount of time and money. It’s not the $4,000 per PET scan that we’re worried about. It’s the millions of patients that are suffering while we don’t have a treatment. If we can run these trials faster, that will get us closer to ending this disease,” Bateman stated.