New Alzheimer’s Blood Test May Detect the Disease 20 Years Before Symptoms

Here’s what we know.

By Madeline Merinuk
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Dr. Oz Gets Tested for His Alzheimer’s Risk (3:29)

The diagnosis of Alzheimer’s is never pleasant news, and medical researchers have been studying different prevention methods for years. Some research indicates that exercise can reduce your risk of developing Alzheimer’s in the future. But now experts are saying there may be a way to detect changes in the brain that are consistent with Alzheimer’s disease and may occur up to 20 years before symptoms arise, thanks to a new blood test. Though this is an experimental screening tool that's not yet approved by the FDA, it's an interesting theory that doctors are working to understand further.

According to a study published by the Centers for Disease Control and Prevention (CDC), in 2014, Alzheimer’s and related dementias affected about 5 million Americans age 65 and over, or 1.6 percent of the population. There is no single cause of Alzheimer’s, but it is believed by experts to be a combination of aging, genetic, lifestyle, and environmental factors. This new blood test, however, can detect the brain changes that are associated with Alzheimer's diagnosis, which can allow patients to start prevention methods earlier than usual. 

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What Makes This Blood Test Different?

Researchers from Washington University School of Medicine in St. Louis were the first to conduct this blood test. These researchers conducted an earlier version of this test about two years ago. In the test, researchers used a technique called “mass spectrometry” to precisely measure the amounts of two forms of amyloid beta in the blood: amyloid beta 42 and amyloid beta 40. They tested 158 people over the age of 50, and took a blood test and a PET scan from each person. Researchers found that the blood tests were accurate to the PET scans 88 percent of the time, which was “promising, but not accurate enough for a clinical diagnostic test,” according to Science Daily. 

To improve the test’s accuracy, the researchers then incorporated common Alzheimer’s risk factors, such as age and a genetic variant called APOE4. When these factors were incorporated, test accuracy raised six percent, raising the blood test accuracy to 94 percent. 

Dr. Richard Isaacson, director of the Alzheimer’s Prevention Clinic at Weill Cornell Medicine, explained to DoctorOz.com how this cutting-edge blood test directly shows identifiers of Alzheimer’s. According to Isaacson, these researchers at Washington University School of Medicine reported that this new blood test can actually measure levels of the Alzheimer’s protein amyloid beta in the blood, and they can use these levels to predict whether these damaging clumps of protein have accumulated in the brain. 

In a brain with Alzheimer’s disease, these proteins form plaques in the brain that begin to appear before memory loss begins, so this blood test has the ability to identify those who may be on track to develop this disease before symptoms arise.

According to Isaacson, this disease starts “brewing in the brain” up to two decades before it can be formally detected, and that’s why this new blood test is such an exciting progression. “The idea is if we can intervene at an earlier stage when the disease is already developing, that could be huge,” he says.

This new blood test, which yields a 94 percent rate of accuracy when combined with age and genetic testing, will be beneficial to patients for many reasons. One reason, Isaacson says, is because PET scans (currently one of the only methods of identifying signs of Alzheimer’s) are very expensive, typically costing thousands of dollars, and this simple blood test will be more cost-effective for patients. According to Randall J. Bateman, the Charles F. and Joanne Knight Distinguished Professor of Neurology, this test will potentially screen “thousands of people a month,” meaning that doctors can more efficiently enroll participants in clinical trials. 

Isaacson explained that this test is not yet available to consumers because it has to go through more screening tests and regulations, but it is about three to five years coming out. In the meantime, you may be able to help reduce your risk of developing Alzheimer’s and other dementias by practicing different methods, such as daily exercise, editing your weekly grocery list, and challenging your brain.

Related:

Dr. Oz: My Mom Has Alzheimer's & I Missed the Signs

The Anti-Alzheimer's Grocery List

7 Tips to Help Prevent Alzheimer's Disease

Article written by Madeline Merinuk