Scientists have been searching for an easier way to diagnose Alzheimer’s disease for years. Now, a new study suggests a new blood test may hold the key. The study, published in the journal Nature Medicine in February of this year, showed that a protein in the blood called neurofilament light chain (NfL) began to increase six to eight years before symptoms appeared in people with familial Alzheimer’s. Also known as dominantly inherited Alzheimer’s, this form of dementia involves a rare, inherited gene that causes Alzheimer’s to develop by the age of 60.
“This is a powerful finding,” says Eric McDade, DO, Associate Professor of Neurology at Washington University and Associate Director of the Dominantly Inherited Alzheimer’s Network (DIAN) Trials Unit. “Using a blood test, we can actually identify what we think is an important marker for someone’s risk of developing cognitive impairment and brain atrophy up to seven years before disease onset.”
NfL is a protein that has been known to scientists for some time. It signals damage to neurons in the brain. It is often found at increased levels in people with stroke, traumatic brain injury, Alzheimer’s and other cases of memory and thinking problems. Previously the best way to test NfL was through spinal fluid. This study showed that the new blood test is as effective at measuring increases in NfL as spinal fluid testing.
The study was conducted with participants in the DIAN study. Blood tests comparing this population to a control group without the familial gene found that NfL began to increase in those carrying the gene about six to eight years prior to expected symptoms. The control group did not show such an increase.
“The next step is to study the test in a broader population of people at high risk for developing Alzheimer’s disease but prior to the onset of cognitive symptoms,” explains Dr. McDade. “If these studies show the same results, we could see the test used more widely in the near future.”
If proven effective in more studies, the blood test could initially be most helpful in Alzheimer’s clinical trials to track disease progression and treatment effectiveness. One day however, it could be used as a screening tool to determine if additional testing is needed.
“This could be groundbreaking for the field of Alzheimer’s research,” concludes Dr. McDade. “Combining this blood test with medications currently being tested to slow or stop the disease before symptoms occur has the potential to dramatically change the lives of millions of people.”