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It’s a big year in the world of Alzheimer’s research. In early July, the FDA approved the Alzheimer’s drug Leqembi, which is the first drug to show clinical evidence of slowing down cognitive decline. A second drug from pharmaceutical giant Eli Lilly has also shown promise with a recent clinical trial showing it can slow the rate of cognitive and functional decline by 35 percent. The experimental drug is expected to get FDA approval by the end of this year. Both drugs have the potential to add years to a person with Alzheimer’s. There’s only one catch — the disease has to be detected early enough for these treatments to work.
Doctors will have to decide which diagnostic tests are worth ordering, and who to use them on if there is limited availability. But instead of waiting around hoping to get selected for testing, why not do it yourself?
On Monday, Quest Diagnostics announced the first consumer-based diagnostic blood test for Alzheimer’s. People will now be able to identify their risk of developing Alzheimer’s without having to wait weeks for a doctor’s appointment.
“This is really exciting for the Alzheimer’s field. We are now getting better at detecting diseases in the earliest stages, which means we may be able to do something about it before the brain has any degeneration,” says Dr. Kellyann Niotis, a preventive neurologist who specializes in neurodegenerative disorders and a member of the Flow Advisory Council. However, she cautions that people should be careful about relying only on blood tests to detect Alzheimer’s. While convenient, amyloid blood tests are not the most accurate options and can lead to unnecessary worry if people cannot interpret the results correctly.
If you’re worried about your health and thinking about buying one of these tests, read below on everything you should consider before you click ‘add to cart.’
How the Alzheimer’s blood test works
The AD-Detect blood test measures plasma — a light yellow liquid mixed with your blood that holds salt, water, and enzymes — from a single blood draw. Diagnosticians look for the ratio between two abnormal proteins held in plasma known as Aβ42 and Aβ40. These are biomarkers for amyloid beta plaques, a hallmark of early Alzheimer’s. The test uses the same technology as another Alzheimer’s diagnostics test from Quest that’s currently being used by medical doctors.
The benefits of the Alzheimer’s blood test
Dr. Niotis says the only true way to diagnose Alzheimer’s disease is with a brain biopsy, but it’s not a feasible or safe option for every person to have minor surgery for diagnosis. Instead, doctors rely on spinal taps to test the ratio of Aβ42 and Aβ40 and to detect signs of tau protein. However, doing this procedure can be invasive and painful. Brain scans are another option for imaging any biomarkers that would suggest possible Alzheimer’s, though these are costly and may not be fully covered by insurance. There’s also the issue of radiation a person is exposed to with each imaging session.
Blood tests are cheaper and a significantly less tedious way to detect Alzheimer’s. With the AD-Detect test, people can purchase the blood test kit through the company’s website without the need for a doctor’s visit. When you order your test, you also gain access to Quest’s independent physician network where you can choose one of 2,100 clinics to get blood drawn. Test results are delivered in a secure patient portal where a report will break down your results in an easy-to-read format.
“We are seeing much attention on emerging therapies for Alzheimer’s disease, but with new treatment options will come the need to make screening and diagnosis more widely available. Blood tests like AD-Detect hold incredible potential to make Alzheimer’s disease risk assessment both accessible and convenient,” says Dr. Michael K. Racke, the medical director of neurology at Quest Diagnostics in a press release. “We’re also seeing a push from consumers who have a desire to take more control of their health, including within more advanced areas like Alzheimer’s disease risk assessment.”
The limitations of the Alzheimer’s blood test
For decades, neuroscientists have followed the amyloid hypothesis. This suggests Alzheimer’s disease happens because a build-up of amyloid-beta plaques disrupts cell-to-cell communication and instigates inflammation in the brain. In recent years, however, this line of thinking has been called into question. “We know that amyloid is associated with Alzheimer’s disease but it is more of a biomarker of an ongoing problem,” Dr. Niotis explains. “It could cause some problems, but it probably isn’t the primary driver.”
In other words, having amyloid in your blood does not mean you currently have or will get Alzheimer’s disease. In fact, Dr. Niotis points out that a third of people with a positive amyloid result for blood tests never go on to develop Alzheimer’s.
Another concern with purchasing this new test is the lack of clinical trials to support the idea that can predict whether a cognitively unimpaired person will transition to cognitively impaired. “There is a lack of data to support the broad use of these tests in primary care settings, let alone individually by consumers at home. As such, the Alzheimer’s Association does not endorse the use of AD-Detect by consumers,” Dr. Rebecca Edelmayer, the senior director of scientific engagement for the Alzheimer’s Association told Flow in an email. “We challenge Quest to pursue a path of FDA approval that demonstrates, rigorously, that this test is valuable to clinicians and patients as part of the diagnostic process.”
How much is the Alzheimer’s blood test?
Everyone over the age of 18 can purchase the AD-Detect blood test, but at a hefty price tag of $399, people need to consider whether they truly need it. Dr. Niotis believes no one should do a test without the consultation of a healthcare provider who can understand and interpret the exact risk to people.
If someone still wants to undergo a blood test, Dr. Niotis says they should ask their doctor for one that measures tau protein. “P-tau217 is actually a better indicator of cognitive impairment or progression to cognitive impairment than amyloid,” says Dr. Niotis. Some blood tests — but not Quest’s AD-Detect — test both amyloid and tau levels.
Who benefits the most from a diagnostic Alzheimer’s blood test?
The people who would benefit most from these Alzheimer’s tests are people with a family history of Alzheimer’s or who have genes that increase their risk of developing it later in life. Another group is people who are already experiencing memory loss or potential cognitive issues. This includes individuals who had brain trauma or a head injury. Age is another risk factor for Alzheimer’s, so any screening would be especially helpful for people 65 years or older.
With the number of dementia cases worldwide projected to reach 14 million by 2060, it’s important to talk to your doctor about the possibility of Alzheimer’s. If anything, the AD-Detect test can serve as a starting point for facilitating this important conversation.