''This is a simple test that has high accuracy and can be run from a single drop of blood," says Robert Nagele, PhD, a professor of medicine at the University of Medicine and Dentistry of New Jersey School of Osteopathic Medicine. He is also founder of Durin Technologies Inc., the company that is developing the test.
The research results on the new test are published online in PLoS ONE.
His test is one of numerous such tests under study, says Heather Snyder, PhD, a spokesperson for the Alzheimer's Association, who reviewed the research results. "Many labs are looking at this. They are all in the very preliminary, very early stages. We all know we need an accurate, relatively noninvasive way to diagnose Alzheimer's."
Last month at the Alzheimer's Association International Conference, Australian researchers reported good results for another blood test for Alzheimer's under development. It works by determining the amount of amyloid plaque, associated with the disease, in people's brains.
An estimated 5.4 million Americans have Alzheimer's disease, the most common form of dementia, according to the Alzheimer's Association.
Doctors use brain imaging, evaluation of behavior, psychiatric tests, and other means to diagnose the disease. None are highly accurate, and some are costly and not practical to use on a widespread basis, experts say.
The only definitive way to diagnose the disease is by direct examination of brain tissue after the patient dies.
Nagele's test looks for antibodies in the blood specific to the disease. Alzheimer's is believed to start up to 10 years or so before symptoms are noticeable.
Before symptoms occur, these brain changes are under way, he tells WebMD. "Brain cells die and when they die, they pop, they explode, like a water balloon breaking."
The contents of those dying cells spill partially back into the blood. "Your body makes antibodies against the cell debris," he says. "We believe that happens so it can facilitate the cleanup of the cell debris."