Is it possible that a simple blood test could diagnose Alzheimer’s as accurately as the more expensive and invasive tests currently in use? A recent study says it’s not only possible, but could become available to the public in the next few years.
Such a test would fulfill a longstanding goal for doctors and scientists who work with age-related cognitive decline. They see an inexpensive and accurate blood test for Alzheimer’s as the key to better treatment and control of the disease.
A study funded by the National Institutes of Health and published in Nature’s Medicine found that a blood test given to 400 people could diagnose Alzheimer’s as accurately as current tests. Those current methods include expensive PET scans and spinal fluid tests that require a spinal tap.
“The considerable time and resources required for screening research participants with PET scans and spinal taps slow the pace of enrollment for Alzheimer’s disease treatment studies,” Dr. Richard J. Hodes, director of NIH’s National Institute on Aging (NIA), said in a news release about the study. “The development of a blood test would enable us to rapidly screen a much larger and more diverse group of volunteers who wish to enroll in studies.”
Blood Test Separates Alzheimer’s From Other Types of Dementia
An international team of researchers led by Dr. Adam Boxer at the University of California, San Francisco developed the blood test. They tested blood samples from participants in an ongoing memory study at the UCSF Memory and Aging Center.
As detailed in the study, the blood test developed by the researchers measures the concentration of pTau181 in plasma, the liquid part of blood that carries cells. Existing research associates changes in tau protein levels with development of Alzheimer’s disease.
The blood test accurately diagnosed those with Alzheimer’s. It also separated them from healthy people or those with a different type of dementia. The results are encouraging and could prove a game-changer in the battle against cognitive impairment.
Detecting Alzheimer’s Disease Early
The blood test is faster, less costly and less invasive than current tests. The blood test may also detect signs of Alzheimer’s at a much earlier stage, making the disease easier to treat. An accurate blood test could even let asymptomatic people know they are developing the tau proteins associated with the disease long before they feel its impact.
Researchers in Sweden also used the blood test and had similar results, adding weight to the study’s findings. Swedish researchers followed participants in their trial for several years. They found that high levels of ptau181 in blood plasma, even in healthy people or those with mild cognitive impairment, may predict who develops Alzheimer’s later in life.
This research is timely. Almost six million people in the United States and 30 million worldwide are diagnosed with Alzheimer’s disease. As the world population ages over the next two decades, experts expect those numbers to grow.
Maria Carrillo, chief science officer at the Alzheimer’s Association, told the New York Times: “This test really opens up the possibility of being able to use a blood test in the clinic to diagnose someone more definitely with Alzheimer’s. Amazing, isn’t it? I mean, really, five years ago, I would have told you it was science fiction.”