What to Know About the New Blood Test for Alzheimer’s Disease
Key takeaways:
It can be difficult to diagnose Alzheimer’s disease. There’s no single test that can detect the disease, and symptoms can overlap with other conditions.
Scientists recently developed a new test that measures levels of proteins in the blood that are high in people with Alzheimer's. However, this test hasn’t yet been approved by the FDA for everyday use.
Current research suggests this blood test may help diagnose people with Alzheimer's more quickly and more accurately than current tests.
Alzheimer’s disease is a common condition in the US. More than 1 in 10 adults over the age of 65 have it.
People with Alzheimer's may have trouble with memory, decision-making, and other daily tasks. But the symptoms can easily be confused with memory changes that occur normally with age. For this reason, it can be difficult to diagnose Alzheimer’s, especially in earlier stages.
Fortunately, scientists have developed a new blood test that may be able to detect the condition sooner.
How is Alzheimer’s disease diagnosed?
The blood test for Alzheimer’s disease is relatively new. So, before going over the specifics, it helps to understand how the condition is typically diagnosed.
It starts with observing someone’s symptoms. The early symptoms of Alzheimer’s can be hard to spot. It can also be hard to face the possibility that you or someone you know might have it. Family and friends often notice these signs first.
In addition to memory loss, people with Alzheimer’s may also experience:
Trouble with directions
Forgetting where they are
Problems with language
Changes in mood
Spending more time alone
Difficulty managing finances
Difficulty with planning
How do you diagnose dementia? It often takes time. Learn about the process and the testing along the way.
What to say to someone just diagnosed with Alzheimer’s: It can be hard to know the best way to be supportive. An expert explains what to say and what not to say.
Is it a ‘senior moment’ or dementia? Memory lapses are normal as you get older. Here’s how to tell the difference between normal aging and dementia.
If you have symptoms of dementia, your primary care provider can perform a series of tests that can help figure out if they could be Alzheimer’s. These include:
Cognitive tests: usually a series of questions and tasks that help evaluate your thinking
Blood and urine tests: can help rule out other conditions like a urinary tract infection (UTI) or electrolyte imbalance
Imaging tests of the brain: can also help to rule out other causes
These test results can provide important information about your health. But it can still be hard for your primary care provider to know for sure that you have dementia. Currently, there’s no single test that detects Alzheimer's with 100% certainty. But a few additional tests can help.
How does an Alzheimer’s blood test work?
Alzheimer’s disease is caused by changes in the way cells in the brain talk to each other. Scientists believe that abnormal levels of proteins — called beta-amyloid and tau — cause this to happen. Everyone has these proteins in their body. But levels are higher in people with Alzheimer’s.
There are a few tests that healthcare professionals can use to measure levels of these proteins:
Lumbar puncture: This is often referred to as a spinal tap. It’s a procedure that uses a thin needle to collect a sample of fluid from the area around the spinal cord.
PET imaging: This is an imaging technique that scans your brain. It’s similar to getting an MRI.
Blood test: This is a newer type of test that measures levels of the beta-amyloid and tau proteins in the blood.
The blood test is a faster, easier way to measure these proteins. Spinal taps and PET scan tests are a bit more involved. And they can’t be performed in a regular healthcare office. This can also delay the time it takes to get results.
The simple blood test can be performed at the doctor’s office and provide results more quickly. However, it’s important to note that there are no approved blood tests at the moment that can diagnose Alzheimer’s. But hopefully that will change soon.
How accurate is blood testing for Alzheimer's disease?
Any test that’s used to diagnose a condition, including Alzheimer’s disease, needs to be accurate to make sure the diagnosis is reliable.
This recent study evaluated the new blood test in over 1,000 older adults. The blood test detected Alzheimer’s disease with about 90% accuracy, which is very high. In comparison, standard methods used to diagnose Alzheimer's are about 60% to 70% accurate. Lower accuracy means the current tests may miss a diagnosis.
Scientists hope that this new blood test can be used to diagnose adults with Alzheimer’s more quickly and accurately than current methods. An earlier diagnosis means that people with Alzheimer's can be treated sooner. It may also help researchers discover new therapies.
Can you get a blood test for Alzheimer's disease?
This new blood test seems very promising, but the FDA hasn’t approved it yet. So, it’s not available yet for everyday use.
All tests and medicines must first be reviewed by the FDA to make sure they’re safe and effective. It can take a long time for a test or medicine to be approved. If the FDA approves this blood test, it will also provide guidance on who’s eligible to take it. It’s not yet known if the test will be covered by Medicare.
The bottom line
For many years, scientists have worked hard to find a test that can accurately diagnose Alzheimer’s disease. A new blood test may help detect Alzheimer’s more quickly and accurately than current methods. But this new test isn’t yet approved or available. If you have concerns about a possible Alzheimer’s diagnosis, reach out to your primary care provider. They can answer your questions about a potential dementia diagnosis.
Why trust our experts?
References
Alzheimer’s Association. (n.d.). Alzheimer's disease facts and figures.
National Institute on Aging. (2024). What happens to the brain in Alzheimer's disease? National Institutes of Health.
National Institutes of Health. (2024). Accurate blood test for Alzheimer’s disease.
Palmqvist, S., et al. (2024). Blood biomarkers to detect Alzheimer disease in primary care and secondary care. JAMA.
U.S. Food and Drug Administration. (2020). What does FDA regulate? A guide for health professionals.
