What’s next for Alzheimer’s blood tests? Experts predict the future of dementia detection
The Alzheimer’s blood test has been climbing headlines as families, patients and clinicians ask whether a simple draw can replace lumbar punctures and PET scans, and whether it can catch the disease before symptoms take hold. Recent studies suggest the answer is inching closer to yes, though researchers are urging caution as the science moves from lab to clinic.
Here’s what the latest research shows, what experts are saying and where the technology could go next.
How Accurate Is the Alzheimer’s Blood Test
Accuracy is the headline finding driving most of the current momentum. A study published in JAMA in October 2024 examined 1,213 patients evaluated for cognitive symptoms in Sweden between February 2020 and January 2024, comparing blood-test results across primary care and secondary care cohorts. The blood test, which measures Alzheimer’s-related proteins, detected the disease’s biological markers with roughly 90% accuracy, outperforming standard clinical evaluations.
Researchers stressed the test is a diagnostic tool, not a standalone answer.
“We see this as a major step towards global clinical implementation of an Alzheimer’s blood test,” said senior author Oskar Hansson, M.D., Ph.D., at Lund University. “It highlights the need for Alzheimer’s biomarkers in making a correct diagnosis more of the time. The next steps include establishing clear guidelines for how an Alzheimer’s blood test can be used in clinical practice, preferably by implementing these tests first in specialist care and then in primary care. This work is currently ongoing.”
A separate 2024 study published in Nature Medicine tested a blood measure of the biomarker %p-tau217 against gold-standard methods including PET brain scans and cerebrospinal fluid tests. Researchers evaluated 1,422 participants from Sweden and 337 from the United States. The blood test performed as well as FDA-approved CSF tests for identifying amyloid plaques and, in some analyses, performed even better for detecting tau tangles. Overall, the test correctly identified Alzheimer’s-related pathology in roughly nine out of 10 people with cognitive impairment, with accuracy approaching 95% when researchers used a two-cutoff approach that flagged borderline results as “indeterminate.”
What the Alzheimer’s Blood Test Means for Early Diagnosis
The appeal of a blood-based test is practical, since it could reduce reliance on lumbar punctures and PET imaging, which are invasive, expensive or difficult to access. Study authors emphasized that the test is intended for people already being evaluated for memory or thinking problems, not as a screening tool for the general public, and that results should be interpreted alongside symptoms, medical history and other clinical findings.
Doctors treating Alzheimer’s say faster, cheaper diagnostics matter now that disease-modifying therapies exist.
“I expect several other tests will quickly gain FDA approval. Because we have disease-modifying treatments for Alzheimer’s disease, there is now an imperative to detect and treat our patients quickly,” Dr. Andrew Budson, lecturer in neurology at Harvard Medical School and chief of Cognitive and Behavioral Neurology at VA Boston Healthcare System, said, per Harvard Health. “Just like in a patient in whom cancer is detected, the treatment doesn’t need to be initiated in a week, but six months is too long, and treatment would ideally begin within two months. Blood-based biomarkers will be crucial to help make this scenario into a reality.”
Predicting Alzheimer’s Risk Before Symptoms Appear
Beyond diagnosis, researchers are exploring whether blood tests can predict future risk in people who feel fine today. A new study presented at the Alzheimer’s Association International Conference followed more than 2,600 older adults and found that symptom-free adults with the highest levels of p-tau217 had a 38% chance of developing cognitive impairment within five years, a figure that climbed to 78% at 10 years.
Dr. Reisa Sperling, the study’s senior author, urged patience.
“Wait and get tested when you can potentially do something about it,” Sperling told ABC News. “At this point it wouldn’t change what I would tell someone to do. I’d still tell them to eat well, sleep well, exercise a lot and stay engaged.”
“This is a gradual process where amyloid and tau build up in the brain and this blood-based biomarker is telling you how far you are in that process,” Sperling said.
Outside researchers called the findings promising but noted the tests “are not yet precise enough to guide individualized prognosis,” while adding that the work has “provided a crucial piece of the puzzle.”
Jessica Langbaum of the Banner Alzheimer’s Institute said patient demand is already outpacing the science.
“Already we have people coming saying, ‘I want this blood test. I have a family history of Alzheimer’s disease,’” Langbaum said. “These findings are quite strong,” she added, saying a predictive blood test would be “really important” if future studies identify treatments that can prevent symptoms from developing.
Dr. Kristien Yaffee, vice chair in the University of California, San Francisco’s Department of Psychiatry and Behavioral Sciences, told the Fisher Center for Alzheimer’s Research Foundation that “for some people who discover they have the biomarkers, testing could open a window to embark on interventions that may postpone Alzheimer’s onset.”
What Comes Next for the Alzheimer’s Blood Test
Leading experts see blood tests reshaping both clinical trials and everyday care, but only after larger validation studies and clearer clinical guidelines.
“Blood tests, once they (a) are confirmed in large populations to be more than 90% accurate and (b) become more widely available, show promise for improving, and possibly redefining, the clinical trial recruitment process and the diagnostic work-up for Alzheimer’s,” said Maria C. Carrillo, Ph.D., chief science officer and medical affairs lead at the Alzheimer’s Association. “While at this time doctors in primary and secondary care should use a combination of cognitive and blood or other biomarker testing to diagnose Alzheimer’s, 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.”
Nisenbaum of the Alzheimer’s Drug Discovery Foundation echoed that we’re still in the early innings.
“We’re at the early stages of having doctors understanding how to utilize these tests and how to move forward,” Nisenbaum said. “We know patients and families want the diagnosis, and while these tests are not perfect, these blood tests in combination with cognitive testing may fill a key gap in the field.”
“We don’t recommend that people go out and ask to get a p-tau217 blood test,” she added, “but in the very near future, I hope that that story will change.”
This article was created by content specialists using various tools, including AI.
