Researchers at Washington University School of Medicine developed a blood test that can detect early changes in the brain due to Alzheimer.
In a research paper published in Neurology, the team which includes senior author Dr. Randall Bateman, professor of neurology and first author Dr. Suzanne Schindler, associate professor of neurology, said they can measure the levels of a damaging protein that leads to memory loss and confusion associated with Alzheimer in the blood and use the levels to predict whether the protein is accumulating in the brain.
Protein Clumps Build Up to Two Decades Before the Onset of Symptoms
The study found that when blood amyloid levels are combined with age and the presence of the genetic variant APOE4, those who have early brain changes from Alzheimer's can be detected with 94% accuracy.
The researchers said the works bring it closer to developing a blood test to identify people who will develop Alzheimer's well before symptoms start showing up. As much as two decades before the symptoms of Alzheimer's arises, clumps of the protein begin to build up in brains.
“Right now we screen people for clinical trials with brain scans, which is time-consuming and expensive, and enrolling participants takes years,” said Bateman in a press release announcing the results of the research. “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.” The researchers noted the test they developed may turn out to be more sensitive that a PET brain scan, which is the current gold standard.
Test Could be Available in the Coming Years
The researchers predicted a test could be available for doctors in the next few years but that the benefits of an early detection test will be much greater when treatments are created to stop the progression of Alzheimer's and prevent dementia. As it stands, the researchers said clinical trials of drugs that could stop and/or prevent the disease are hurt by a difficulty in finding people who have Alzheimer's brain changes but aren't also suffering from cognitive problems such as memory loss. With the blood test, clinicians can better screen patients for their trials.
Researchers tested an earlier version two years ago. In this study, the researchers looked at 158 adults over the age of 50 with all but 10 cognitively normal. Each provided a blood sample and underwent a PET scan. The researchers then classified each blood sample and PET scan as either amyloid positive or negative. They discovered that 88% of the time the blood test matched the PET scan. To improve the accuracy the researchers included risk factors such as age and the genetic variant called APOE4 and that increased the accuracy of the blood test to 94%.
Blood Test Could Reduce the Number of PET Scans
The researchers also found that if patients are prescreened with a blood test and then followed by a PET scan for confirmation it could lower the number of PET scans by as much as two thirds.
“If you want to screen an asymptomatic population for a prevention trial, you would have to screen, say, 10,000 people just to get 1,500 or 2,000 that would qualify,” Bateman said. “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.”