First Alzheimer's Blood Test Approved in the US

For many years, the only way to positively diagnose Alzheimer’s disease was studying the brain after a patient had died. But medical advances like advanced scanning combined with memory tests and family history has made it easier for physicians to diagnose the disease.

Now the Food and Drug Administration has approved a new blood test that will help doctors zero in on the disease earlier.

What Is Alzheimer’s Disease?

Alzheimer’s disease is a progressive form of dementia that destroys cognitive skills, including memory. It also kills more people than breast cancer and prostate cancer combined, according to the Alzheimer’s Association. Currently, there are nearly 7 million Americans living with Alzheimer’s disease, but experts predict that number will rise to 13 million by 2050.  

Alzheimer’s disease tends to develop slowly and progress gradually, resulting in symptoms that go unnoticed, mistaken for other conditions or chalked up to aging. By the time Alzheimer’s is detected, many patients are diagnosed with mild dementia due to Alzheimer’s disease – the third stage of Alzheimer’s disease.  

However, if a patient can be diagnosed earlier in the disease process, researchers feel they might have better outcomes with targeted treatments that can slow the disease progression and maintain brain health.  

How Alzheimer’s Has Historically Been Diagnosed

Historically, diagnosis has been limited. Magnetic resonance imaging (MRI) scans can show structural degeneration, brain cell activity changes and/or biological deviations, but often can’t confirm if these changes are caused by Alzheimer’s, another condition or aging. Cerebral spinal fluid (CSF) tests, which involve an invasive low back puncture, can identify Alzheimer's biomarkers, but the levels, even in the same sample, often vary significantly from institution to institution and across different testing platforms, according to the Alzheimer’s Association. Positron emission tomography (PET) scans that specialize in visualizing amyloid plaques and tau protein tangles -- hallmark sign of Alzheimer’s – can be accurate, but technically challenging to perform and require strict quality control. Moreover, these tests are costly, time consuming and expose patients to radiation. Some clinicians don’t consider their results definitive and prefer to order these PET scans as secondary tests to confirm an Alzheimer’s diagnosis.      

New Blood Tests

Laboratories are working on blood tests that can consistently measure changes in Alzheimer’s biomarkers before and after symptoms begin appearing. A couple of years ago, University of Washington developed a laboratory test, called soluble oligomer binding assay (or SOBA), to measure beta-amyloid oligomers in the blood, an early sign of Alzheimer’s disease that is thought to trigger and progress the disease, according to a study published in the Proceedings of the National Academy of Sciences.  

More recently, the US Federal and Drug Administration (FDA) approved the first blood test for Alzheimer's disease. Fujirebio Diagnostics, a biotechnology company, created a test –the Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio. It measures the levels of and ratio between beta-amyloid 1-42 and pTau217 in plasma. The presence of these proteins in plasma suggests amyloid plaques in the brain.  

The Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio multi-center clinical study included nearly 500 individual plasma samples from cognitively impaired adults. Samples were tested using Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio and compared with amyloid PET scan or CSF test results. The FDA evaluated the results and found:

• Almost 92 percent of people with positive results had the presence of amyloid plaques confirmed by a PET scan or CSF test result.
• 97 percent of people with negative results. The absence of amyloid plaques was confirmed by a PET scan or CSF test result.  
• Less than 20 percent of people in the study had an undetermined result.

The FDA concluded that this new test is reliable, minimally invasive, easier to perform and more accessible than other Alzheimer’s tests. Since it’s a blood draw, the only risk associated with the test is a possible false positive or false negative result. This is problematic as it contributes to a wrong diagnosis. However, results should be interpreted in combination with other patient clinical information. The test is meant to be used by a specialist in patients with signs and symptoms of cognitive decline. It wasn't designed for or intended to be a screening.

Alzheimer’s seems to be triggered by a handful of risk factors including age, genetics, head injuries, an unhealthy lifestyle, heart disease and environmental exposures. Currently, there is no proven method of prevention, but you can help lower your risk of dementia by living a brain-healthy lifestyle and working with your primary care physician.

MDVIP-affiliated physicians provide patients with the MDVIP Wellness Program, which screens for components of a brain-healthy lifestyle such as exercise, nutrition, sleep, substance use, emotional health (including stress), blood pressure and social connections. Doctors use results from these screenings to develop a personalized wellness program for you that can focus on brain health. Doctors also have more time to get to know you and your lifestyle, which may help them recognize early signs of cognitive decline. 

If you’re looking for a primary care physician, consider partnering with an MDVIP-affiliated physician. Find an MDVIP affiliate near you »