A Simple Blood Test for Alzheimer’s? ‘It’s Not That Far Away’ 

A new study adds to a growing sense of optimism that doctors could soon have a faster, simpler and more affordable way to tell if a patient’s symptoms of memory loss and confusion are caused by Alzheimer’s disease, the most common form of dementia that affects nearly 7 million older Americans.

A team of researchers based in Sweden found that a blood test was about 90 percent accurate in diagnosing Alzheimer’s disease in people experiencing thinking and memory problems. In the research study, primary care physicians were 63 percent accurate in an Alzheimer’s diagnosis when not using the blood test; specialists were 73 percent accurate when not using the test, which identifies a specific protein in the blood that serves as an indicator for the buildup of amyloid plaques and tau tangles, two defining characteristics of Alzheimer’s disease.

The study was presented at the 2024 Alzheimer’s Association International Conference and published in the medical journal JAMA.

This blood test and others like it are not widely available to patients outside of research studies, but they could be soon, and that would be a “revolutionary change,” says Paul Newhouse, M.D., director of the Center for Cognitive Medicine at Vanderbilt University Medical Center and clinical core director for the Vanderbilt Alzheimer’s Disease Research Center. 

What doctors rely on now when making an Alzheimer’s diagnosis is a patchwork of physical and cognitive tests and pricey brain scans or invasive spinal taps. With more studies like this latest one, blood tests could “serve as the first line of defense in diagnosing the disease,” Howard Fillit, M.D., cofounder and chief science officer of the Alzheimer’s Drug Discovery Foundation, said in a statement.

A study published earlier this year in JAMA Neurology examined the accuracy of a blood test that identifies the same protein in the blood, called p-tau217.  The research team found that the blood test was more than 90 percent accurate and was on par with the gold-standard diagnostic tools — positron emission tomography (PET) imaging and cerebrospinal fluid collected from a lumbar puncture — in detecting the brain changes associated with Alzheimer’s disease.

Previous studies have produced promising results, too, so evidence continues to build for the use of blood tests in clinical settings, says Ronald Petersen, M.D., director of the Mayo Clinic Alzheimer’s Disease Research Center and the Mayo Clinic Study of Aging.“I think this is a step forward; this is important. This is something that the field has been waiting for,” Petersen told AARP. 

To learn more about a potential blood test for Alzheimer’s and dementia, from AARP, CLICK HERE.