- The early diagnosis of Alzheimer’s disease is important for the medications currently available for the condition.
- Right now, researchers are focusing on finding new ways to better diagnose early Alzheimer’s disease, such as blood tests.
- Researchers from Lund University have found that a new blood test called PrecivityAD2 is about 90% accurate in identifying Alzheimer’s disease in people experiencing cognitive symptoms.
As with any disease, the earlier a person receives a diagnosis the better.
This is especially true with Alzheimer’s disease — although there is currently no cure for the condition, there are medications available for the earliest stages of the disease to help manage symptoms and potentially slow progression.
Recently, researchers have been focusing on finding new ways to better diagnose early Alzheimer’s disease. One such method is the use of blood tests to look for specific biomarkers associated with the condition.
At Lund University in Sweden, researchers have found that a new blood test called PrecivityAD2 is about 90% accurate in identifying Alzheimer’s disease in people experiencing cognitive symptoms.
“Early diagnosis is crucial as new treatments that slow the disease’s progression are developed,” says Oskar Hansson, MD, PhD, professor of neurology at Lund University and co-lead author of this study recently published in the Journal of the American Medical Association (JAMA) and presented at Alzheimer’s Association International Conference 2024.
“For example, two immunotherapies have recently been approved in the U.S. and are expected to be available in Europe soon. An early and accurate diagnosis is also vital for facilitating research into new treatments.”
For this clinical study, researchers tested the PrecivityAD2 blood test made by C2N Diagnostics, LLC.
The test works by measuring a combination of two ratios within a blood sample:
Both tau and amyloid-beta proteins are currently considered pathological hallmarks of Alzheimer’s disease.
“Blood tests for early detection of Alzheimer’s disease are crucial because they offer a less invasive, more cost-effective, and accessible alternative to current methods like cerebrospinal fluid tests and amyloid PET scans,” Verna Porter, MD, a board certified neurologist and director of the Dementia, Alzheimer’s Disease, and Neurocognitive Disorders at Pacific Neuroscience Institute in Santa Monica, CA — who was not involved in this study — told Medical News Today.
“Early and accurate diagnosis can lead to timely intervention and better patient outcomes,” she said.
About 1,200 study participants with an average age of 74 years old were tested with the PrecivityAD2 blood test.
Of the participants, 23% had subjective cognitive decline, 33% had dementia, and 44% had mild cognitive impairment. About 50% of participants showed Alzheimer’s disease pathology through primary and secondary care testing.
Of the 698 participants previously seen at a memory clinic, the PrecivityAD2 test was about 90% accurate in identifying the presence of Alzheimer’s disease, while specialists were only 73% valid.
And for the remaining 515 participants originally seen by a primary care doctor, the test was again about 90% accurate in diagnosing Alzheimer’s disease, compared to primary care physicians being 61% correct.
“Primary care doctors’ accuracy in identifying Alzheimer’s disease was 61%, while specialist physicians were correct 73% of the time,” says Sebastian Palmqvist, MD, PhD, associate professor of neurology at Lund University and co-lead author of this study. “This underscores the lack of good, cost-effective diagnostic tools, particularly in primary care, and indicates the potential improvement in diagnosis with the adoption of this blood test in healthcare settings.”
After reviewing this study, Porter told MNT that the high diagnostic accuracy and robustness of the blood biomarkers — Amyloid Probability Score 2 (APS2) and p-tau217 — in identifying Alzheimer’s disease across primary and secondary care settings are promising.
“This could significantly improve early diagnosis and patient management, ideally, providing earlier access to treatment.”
— Verna Porter, MD
For the next steps in testing the PrecivityAD2 blood test, Porter said should would like to see validation of the blood biomarkers in diverse international cohorts, especially those with lower amyloid positivity prevalence, as well as the development and evaluation of fully automated immunoassays for easier implementation in clinical labs.
“(Also) conduct further studies to compare the diagnostic performance of the percentage of p-tau217 versus p-tau217 alone,” she continued. “This involves identifying specific clinical settings or patient subgroups where one metric might offer greater diagnostic accuracy or utility over the other.”
“For instance, the percentage of p-tau217 might be particularly useful in patients with certain comorbid conditions, such as chronic kidney disease, which can affect the levels of non-Alzheimer’s related p-tau217,” Porter added. “Understanding these nuances will help tailor the use of these biomarkers to maximize diagnostic accuracy and clinical benefit.”
MNT also spoke with Karen D. Sullivan, PhD, ABPP, a board-certified neuropsychologist, owner of I CARE FOR YOUR BRAIN, and Reid Healthcare Transformation Fellow at FirstHealth of the Carolinas in Pinehurst, NC about this study.
“My first reaction is that the dementia biomarker stakeholder’s have done an excellent job in claiming their turf in the diagnosis of Alzheimer’s disease,” Sullivan said. “The dementia specialist they reference mostly relied on cognitive screening measures and did not administer a comprehensive neuropsychological evaluation. I predict their predictive accuracy would have been much better than 73% if a gold standard cognitive testing approach was used by a board certified neuropsychologist.”
She cautioned that by reducing brain health diagnosis to lab tests only, and forgoing detailed clinical interviews and human-to-human assessments, physicians run the risk of false positive dementia diagnoses, reducing complex neuropathological processes into one neat diagnosis and, in our present care environment, unnecessary treatments with high risks.
“In brain health, structure does not always equal function and many patients with dementia have mixed causes for their symptoms,” Sullivan explained. “Yes, there may be Alzheimer’s related amyloid accumulation but there can also be other pathologies that are contributing. The new Alzheimer’s disease monoclonal antibody treatments have not been tested for safety in mixed etiologies.”
“I think the best approach is to respect biomarkers as one piece of data in a person-centered assessment model and not to forget that our brain is a unique and complex biopsychosocial system different from other body systems. This is the organ of the self and requires a person-centered, multi-faceted, individualistic approach. I don’t want us to lose sight of our humanness in diagnosing dementia.”
— Karen D. Sullivan, PhD, ABPP
