"When you have 90% accuracy," Ilene Rosenthal said, "that's very impressive."
A new study is offering hope for a simple and accurate blood test that can diagnose Alzheimer’s disease in its early stages, the only time when currently available treatments work.
The study led by a group of Swedish researchers and published Sunday in the Journal of the American Medial Association, found that a test based on measuring certain proteins in the brain had about a 90% accuracy rate in diagnosing Alzheimer’s in those with cognitive symptoms. By comparison, primary care doctors and specialists had a 61% and 73% accuracy rate in diagnosing the disease, the study found.
Currently, the disease can be definitively diagnosed only by more expensive and invasive tools such as PET scans and spinal taps. The neurodegenerative disease afflicts more than 6 million Americans, and Baltimore and Maryland have been found to have some of the nation’s highest rates of prevalence.
The blood test in the study and others of its ilk are only available in research trials at the moment. Getting one to the market and available in a primary care physician’s office would represent “incredible progress,” said Corinne Pettigrew, an assistant professor of neurology at the Johns Hopkins University School of Medicine who was not involved in the study.
“This would allow patients to review options for treatments, learn about what to expect of the disease and plan for the future,” said Pettigrew, who leads outreach, recruitment and engagement for the Hopkins Alzheimer’s Disease Research Center.
She said the test also would be important for ruling out Alzheimer’s as the reason for a patient’s cognitive impairment, allowing doctors to seek and treat the actual cause.
The study involved 1,213 people in Sweden whose average age was 74 and who were being evaluated because of cognitive symptoms. According to the paper, Alzheimer’s is often misdiagnosed by primary care physicians and even specialists because of a lack of or limited access to diagnostic tools. That prevents patients from starting treatments for those with early Alzheimer’s, which require test results confirming the disease, the study said.
“The higher diagnostic accuracy of the blood test indicates that it could be suitable for implementation in primary care, but future studies need to examine its effect on clinical care,” according to the study, which was led by Dr. Sebastian Palmqvist, of Lund University in Sweden. “In addition to improving diagnostic accuracy, a positive test result could further support the initiation of widely available treatments.”
Ilene Rosenthal, program director at the Greater Maryland chapter of the Alzheimer’s Association, called the study findings “extremely exciting” for advocates such as her organization who have pushed for more research to understand and treat the devastating disease.
“When you have 90% accuracy,” she said, “that’s very impressive.”
Rosenthal envisions a time when a blood test for Alzheimer’s will be as common and widely available as those that test for cholesterol.
“This should become a normal part of a physical or a wellness visit,” she said.
Alzheimer’s still has no cure, but there are treatments that can ease its symptoms and change its progression if started early enough. That makes the development of a test vital, and it will incentivize patients and doctors to use them, Rosenthal said.
“The real urgency right now is the availability of new treatments. But these treatments are only going to work in the early stages,” she said. “It’s so much better to know than to not know.”
