A recent study shows that new blood tests may help doctors diagnose Alzheimer’s disease faster and more accurately.
Alzheimer’s disease is the most common form of dementia, affecting 6.7 million Americans. As the U.S. population ages, that number is expected to grow to 13 million by 2050.
A study of 1,213 patients in Sweden between February 2020 and January 2024, published on Sunday, found that blood tests that target a form of protein called tau were much more accurate in diagnosing the disease than doctors alone.
In the study, patients who went to a general practitioner or specialist for memory complaints were initially diagnosed through traditional tests. They were then given blood for testing and referred for a confirmatory lumbar puncture or brain scan.
According to the findings of researchers at Lund University, the initial diagnosis by general practitioners was 61 percent accurate and that of specialists was 73 percent. However, the blood test was 91 percent accurate.
New research has found that blood tests that target a form of protein called tau are much more accurate in diagnosing the disease than doctors alone
Scientists believe Alzheimer’s likely results from an abnormal buildup of proteins – amyloid and tau – in and around brain cells.
“Not long ago, measuring pathology in the brain of a living human was considered impossible,” said Dr. Jason Karlawish, a co-director of the Penn Memory Center at the University of Pennsylvania who was not involved in the study. The New York Times.
“This study adds to the revolution that has taken place in our ability to measure what is going on in the brains of living people.”
Although the root cause of Alzheimer’s disease is still under debate, scientists believe the damage likely results from an abnormal buildup of proteins (amyloid and tau) in and around brain cells.
In Alzheimer’s patients, amyloid proteins are not effectively removed from the body and eventually form plaques in the brain. Tau proteins detach from neurons and form tangles.
Both can lead to the death of neurons, making it difficult for signals to travel through the brain.
Blood tests measure a form of tau that correlates with the amount of plaque a person has built up, says Dr. Suzanne Schindler, a neurologist at Washington University in St. Louis.
A high level indicates that there is a good chance that a person has Alzheimer’s, while a low level indicates that this is probably not the cause of the memory loss.
Experts believe that blood tests should only be used by doctors and researchers and should not be available to the general public.
Maria Carrillo, chief scientific officer of the Alzheimer’s Association, says they should only use blood tests that have been proven to have an accuracy rate of more than 90 percent.
The Alzheimer’s Association is working on guidelines and several companies plan to seek FDA approval, which should provide clarity on appropriate use.
The tests are not intended for people who do not have symptoms, unless it is part of participation in research studies, Schindler said.
Alzheimer’s disease is the most common form of dementia, affecting 6.7 million Americans
This is partly because the build-up of amyloid can begin as early as 20 years before the first signs of memory problems. So far, there are no preventative measures, apart from the basic advice to eat healthily, exercise and get enough sleep.
There is currently no cure for Alzheimer’s. New drugs in development, such as donanemab (a twice-daily pill that may reduce levels of a harmful brain protein called amyloid), can only slow the progression of the disease marginally and come with dangerous side effects, such as brain hemorrhages.
Although the drug was initially touted as a possible therapy, a quarter of the patients in the study experienced brain swelling and three people died from brain swelling or bleeding attributed to the drug.
Another drug, Leqembi, works in a similar way to donanemab but can also cause amyloid-related imaging abnormalities (ARIA). These are changes in the brain that can cause bleeding and swelling.
It is FDA approved, but research shows that about 20 percent of people who take the drug develop ARIA, but only 20 percent of those people experience symptoms.