October 1, 2025 | We have entered a new era of science focused on developing tools and technologies to support early detection and diagnosis, said Rebecca Edelmayer, vice president of scientific engagement at the Alzheimer’s Association. The rapid evolution of research has led to the need to systematically collect, review, and distill findings into clear and actionable recommendations for how to use these tools in clinical practice, Edelmayer told Diagnostics World. And from her vantage point, blood biomarker tests for Alzheimer’s disease are in greatest need of this now.
Clinical Practice Guidelines and Other Blood Test Announcements
At its conference held in Toronto over the summer, the Alzheimer’s Association released its first clinical practice guideline focused on blood-based biomarker tests. The full guideline, co-authored by Edelmayer, appeared in the journal Alzheimer’s & Dementia (DOI: 10.1002/alz.70535) and includes recommendations that high-sensitivity blood tests (≥ 90% sensitivity, ≥ 75% specificity) can be used as triage tools and that high-sensitivity and specificity tests (≥ 90%) can be used as an alternative to PET scans or cerebrospinal fluid (CSF) testing.
Although there are other guidelines in development, Edelmayer said the Alzheimer’s Association began with blood biomarker tests in an effort to “keep up with the pace of the science, recognizing that there was a gap in clinical practice and a real need to make sure that clinicians had information at their fingertips to help support their decision-making on really finding the right test for the right patient and using it at the right time.”
Not all blood tests are equal or interchangeable, she cautioned, and the guideline is meant to help clinicians with their decision-making process, which should be a shared process along with the patient that involves discussion of the various pros and cons of using this type of test. Blood tests may “eventually revolutionize our field,” Edelmayer added, but “they’ll never be used in isolation.” They will “always need to be used as part of a comprehensive clinical evaluation.” In other words, blood tests are one tool that can “help aid in the diagnosis of someone with Alzheimer’s disease.”
Beyond the announcement of these newly released clinical guidelines, there were an array of other developments highlighted at the Alzheimer’s Association International Conference, as Diagnostics World previously reported, including blood test updates.
Quanterix announced the commercial launch of its p‑Tau 205 and p‑Tau 212 assays, for instance, which are now available to customers for use on the HD-X or SR-X instruments or through Quanterix’s Accelerator Lab. Another update came from Roche, which received CE marking for its Elecsys pTau181 test to rule out Alzheimer’s disease as the cause of cognitive decline. The company is also currently developing an Elecsys pTau217 blood test.
Blood Biomarker Challenge Aims to Evaluate Alzheimer’s and Dementia Blood Tests
In the UK, an initiative led by the Alzheimer’s Society and Alzheimer’s Research UK is exploring whether a panel of blood tests can complement existing diagnostic pathways in NHS memory clinics. Called the Blood Biomarker Challenge, the initiative began enrolling its first participants this year and hopes to bring dementia blood tests to the NHS within five years.
The READ-OUT (REAl world Dementia OUTcomes) team, led by Dementias Platform UK researchers from the Universities of Oxford and Cambridge, will test multiple new and existing blood tests, looking at a range of dementia types. The ADAPT team (Alzheimer’s disease Diagnosis and Plasma pTau217), led by University College London researchers, will focus on the p-tau217 biomarker in particular. Both teams will explore whether the tests can help detect these diseases at various stages.
Ashvini Keshavan, co-leader of the ADAPT team, senior clinical research fellow, and honorary consultant neurologist at University College London, told Diagnostics World that the ADAPT team has previously assessed the accuracy and performance of the p-tau217 blood test. Next up, her team is focused on determining the impact of on Alzheimer’s disease diagnosis and patient care.
The clinical trial, which recently launched, is aiming to recruit 1,100 participants from about 20 sites across the UK, Keshavan said, and will compare the effectiveness of providing blood test results at three months versus 12 months. The goal is to learn more about whether blood measurements of people with mild cognitive impairment or dementia impacts their onward care, including aspects like treatment decisions, support, and referral to clinical trials. Anticipated challenges include diverse recruitment, ensuring geographical and socioeconomic representation, and maintaining unbiased monitoring.
“Currently, we are working to a timeline of completion of recruitment by September 2027, analysis of the primary outcome by March 2028, and completion of all follow-up by end of March 2029,” Keshavan added. The trial’s success could ultimately influence national guidelines and NHS funding for blood tests in dementia diagnosis.
Regulatory Approval of New Alzheimer’s Blood Test
Earlier this year, the U.S. Food and Drug Administration cleared the first blood test used to help diagnose Alzheimer’s Disease. The Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio from Fujirebio Diagnostics is designed for the early detection of amyloid plaques that are associated with Alzheimer’s disease in patients 55 years and older with signs and symptoms of cognitive decline.
The test, which was developed using research conducted at Lund University in Sweden, Johns Hopkins University, and private collaborators, was reviewed through the FDA’s 510(k) premarket notification pathway and granted Breakthrough Device designation. During review, the FDA evaluated data from a multi-center clinical study of nearly 500 plasma samples from cognitively impaired adults.
The samples were tested by the Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio and compared with amyloid PET scan or CSF test results. In this study, 91.7% of individuals with positive Lumipulse results had the presence of amyloid plaques based on PET scan or CSF test result, and 97.3% of those with negative results had a negative CSF or amyloid PET scan result.
New medications are available to treat this disease, but they are only effective if diagnosed early on, and early diagnosis depends on accurate biomarkers, said Abhay Moghekar, associate professor of neurology at the Johns Hopkins University School of Medicine, whose lab contributed samples and validated the test.
The new test does not provide a definitive diagnosis but rather an amyloid range. Patients with scores above the high-end cutoff have a high likelihood of having Alzheimer’s disease, whereas those below the low range almost certainly do not have the disease. Results need to be interpreted along with other patient clinical information, and roughly 1 in 5 falls into a range that requires additional testing.
Advances in Alzheimer’s Biomarkers, Predictive Tools, and Testing Formats
A study published in Nature Medicine (DOI: 10.1038/s41591-025-03617-7) by researchers at Lund University in Sweden and the University School of Medicine in St. Louis reveals that levels of a protein found in the blood called MTBR-tau243 reflect the amount of tau accumulation in the brain. The findings suggest that this marker could be useful for improving the diagnostic evaluation of Alzheimer’s in clinical practice and for monitoring the effectiveness of targeted therapies used in clinical trials.
Although p-tau217 is seen as a sensitive blood-based biomarker for Alzheimer’s disease, researchers at the Sant Pau Institute in Spain pointed out that its prognostic value remains unclear. To learn more, they measured p-tau217 using a commercially available test across various clinical stages of disease. Findings published in Neurology (DOI: 10.1212/WNL.0000000000213769) support its potential use as a prognostic marker for monitoring disease progression, the authors concluded.
Meanwhile, researchers at the University of Southern California have developed a multiplex test that measures five biomarkers in plasma and serum—including amyloid, tau variants, neurofilament light, and glial fibrillary acidic protein GFAP. Ebrahim Zandi, associate professor in the Department of Immunology and Immune Therapeutics at the USC’s Keck School of Medicine, said his group improved upon existing xMAP technology to make it suitable for Alzheimer’s biomarkers.
He sees the wide availability of the base technology as a notable advantage over other similar methods. The assay’s performance is detailed in a study published in the Journal of Alzheimer’s Disease (DOI: 10.1177/13872877251340999). Moving forward, Zandi intends to validate the method with larger sample cohorts and explore options to make it available for widespread use as a cost-effective Alzheimer’s risk assessment tool, he told Diagnostics World.
Blood Test May Be Able to Detect Signs of ALS Long Before Symptoms Appear
In neurodegenerative news that extends beyond Alzheimer’s and dementia, a new blood test could provide new possibilities for the early diagnosis of amyotrophic lateral sclerosis (ALS), otherwise known as Lou Gehrig’s disease. Researchers at the Johns Hopkins University School of Medicine and the National Institutes of Health, along with the UK Biobank and the University of Turin in Italy, have pinpointed a set of proteins in blood that can detect ALS up to a decade before the onset of symptoms.
The research group used the Olink Explore 3072 platform to explore roughly 3,000 neurological and skeletal muscle proteins in blood samples from more than 600 participants. Thirty-three proteins were found to be “differentially abundant” in the plasma of patients with ALS compared with controls. They then applied machine learning to develop a predictive protein signature that diagnosed ALS with an area under the curve (AUC) of 98.3%. Study results, published in Nature Medicine (DOI: 10.1038/s41591-025-03890-6), suggest that plasma proteins could be a biomarker for this disease, and according to the researchers, could potentially pave the way toward a blood test.
Current diagnosis relies on neurological evaluations and the presence of symptoms, but for the time being, no definitive diagnostic test exists. A test enabling earlier detection of ALS could mean new opportunities to enroll participants in observational studies and offer promising treatments before the disease becomes debilitating, said co-investigator Alexander Pantelyat, associate professor of neurology at the Johns Hopkins University School of Medicine.
The group validated the test across multiple independent groups, including a cohort of over 20,000 participants from the UK Biobank. Blood samples from over 100 individuals that were collected 10 to 15 years before they developed ALS revealed changes in the protein signature identified in the study, suggesting that the biological markers of this disease can be detected long before symptoms show up. Additional research is underway to explore how this protein signature could help track disease progression, assess treatment effectiveness, and inform the development of new diagnostic tools.
Paul Nicolaus is a freelance writer specializing in science, nature, and health. Learn more at www.nicolauswriting.com.