New Alzheimer’s Blood Tests Could Reduce Diagnosis Time by Years …C0NTINUE READING HERE >>>
Key Takeaways
A new blood test for Alzheimer’s shows 91% accuracy in diagnosing the condition, potentially improving early diagnosis and access to treatments.Using blood tests alongside cognitive assessments could reduce the time to diagnose Alzheimer’s, helping more patients access early treatments.Current diagnostic tools like spinal taps and PET scans are less accessible, making the blood test a promising alternative for earlier and more accurate detection of Alzheimer’s.
A recent JAMA study shows that blood tests could significantly improve the diagnosis of Alzheimer’s. Research shows that a test that determines the likelihood of amyloids, specifically, is 91% accurate at detecting the condition.
Experts say faster diagnosis is critical because there are two effective Alzheimer’s treatments currently on the market—Leqembi and Kisunla—as well as others in the pipeline. Both can potentially delay the progression of the disease, but only if patients get the drugs at the earliest stages of Alzheimer’s.
Often, however, patients are not diagnosed until it’s too late to try the medications.
“Blood tests have the potential to increase the accuracy of early diagnoses and maximize the opportunity to access Alzheimer’s treatments as early as possible for better outcomes,” said Maria C. Carrillo, PhD, Alzheimer’s Association chief science officer and medical affairs lead, in a statement about the study.
How Does the New Blood Test Compare to Current Diagnostic Tools for Alzheimer’s?
Different versions of blood tests to detect Alzheimer’s have been on the market for several years, but they’re not widely available and are rarely currently covered by insurance. Their accuracy also varies, Suzanne Schindler, MD, a neurologist specializing in Alzheimer’s disease at the Washington University School of Medicine in St. Louis, told Verywell.
None of the currently available tests have or need to have FDA approval, though that could change under a newly proposed rule. A pre-print study by the Foundation for the National Institutes of Health compared commercially available tests, determining that “some blood tests had accuracy similar to cerebrospinal fluid tests in detecting amyloid plaques and could eliminate the need for an invasive spinal tap or expensive brain scan” according to a press release. The study did not conclude that one test is better than another; the Alzheimer’s Association has convened a panel of experts to develop clinical guidelines for the use of existing tests.
The JAMA study, which was presented at the Alzheimer’s Association International Conference in July, included over 1,200 patients who saw either a primary care doctor or a dementia specialist. Patients were given in-office cognitive and memory tests, a blood test, and were sent for either a spinal tap or a brain imaging test called a PET scan.
“In-office tests and spinal taps or PET scans are the most common current way to accurately diagnose Alzheimer’s disease, but not everyone is referred to or has access to those tests, which can significantly delay the diagnosis,” Schindler said.
Researchers tested all of the blood samples for a protein called phosphorylated tau, which can develop before cognitive issues start and can predict the likelihood of amyloid plaques in the brain. When they compared the results, they found that the initial diagnosis of primary care doctors was 61% accurate, the dementia specialists were 73% accurate, and the blood test was 91% accurate at diagnosing Alzheimer’s.
Blood Tests Should Speed Up Time to Diagnosis
There’s currently a wide range of how long the road to an Alzheimer’s diagnosis can be. Jason Hinman, MD, PhD, Interim Co-Center Director of the Mary S. Easton Center for Alzheimer’s Research and Care at UCLA, pegged it at an average of 18 months. He said that it can be longer when factoring in the time deliberating about whether or not to discuss the subject, the waiting time for tests and evaluations, and frequent inaccurate doctor determinations that there is no significant cognitive problem. The problem is compounded by a shortage of Alzheimer’s specialists, especially for people in rural communities, Hinman said.
Research presented at the Alzheimer’s conference suggested that by 2033, people will wait an average of nearly six years to understand if they could be eligible for new Alzheimer’s treatments if their primary care doctor only used cognitive assessments to make referrals to specialists. The wait time is expected to get worse over time due to an aging population and a declining number of specialists like geriatricians, neurologists, and radiologists.
If blood tests were used to rule out Alzheimer’s, the average wait times would drop to 13 months, researchers say. That’s because the condition could be ruled out sooner, and far fewer patients would need to see a specialist.
The researchers also determined that if blood tests and brief cognitive assessments were used by primary care doctors suggest there is the possibility of an Alzheimer’s diagnosis, wait times to understand eligibility for new treatments would fall to less than six months on average.
“Our results suggest using blood tests to identify potential candidates for treatments could make a significant difference in treating people with early Alzheimer’s,” said lead study author Soeren Mattke, MD, DSc, director of the Brain Health Observatory at the University of Southern California, Los Angeles, in a statement. “Currently, eligible patients are falling outside of the treatment window because it takes so long to receive a diagnosis.”
Shortening the time from symptoms to diagnosis is critical because the currently available drugs to treat Alzheimer’s disease can only be used for patients with mild to moderate cognitive decline. Accurate diagnosis is just as critical, says Schindler. What may initially seem like Alzheimer’s disease could be a medication side effect or a different treatable disease, but not necessarily treatable by drugs prescribed for Alzheimer’s.
What This Means For You
Patients interested in an Alzheimer’s blood test can ask their doctors about it now or ask for a referral to a dementia specialist who may be more likely to know about and even use the tests. It’s unlikely, for now, that the tests will be used alone, and patients should expect a full battery of in-office tests, as well as imaging scans or a spinal tap. While some insurance plans may pay for part of the cost of these blood tests, not all do.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Palmqvist S, Tideman P, Mattsson-Carlgren N, et al. Blood biomarkers to detect Alzheimer disease in primary care and secondary care. JAMA. Published online July 28, 2024. doi:10.1001/jama.2024.13855
Schindler SE, Petersen KK, Saef B, et al. Head-to-head comparison of leading blood tests for Alzheimer’s disease pathology. medRxiv. Preprint posted online July 3, 2024. doi:10.1101/2024.06.12.24308839
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