ISLAMABAD
\nOn August 24, 2026, the U.S. FDA cleared a new single-biomarker blood test to help doctors detect signs of Alzheimer\u2019s disease.
\nThe test helps doctors determine both rule-in (positive result) and rule-out (negative result) assessment of amyloid pathology, a hallmark of Alzheimer\u2019s disease.
\nThe blood test is specifically for older adults 55 and older with signs or symptoms of cognitive decline.
\nOn August 24, 2026, the U.S. Food & Drug Administration (FDA) cleared the use of a new single-biomarkerTrusted Source blood test to help doctors look for signs of Alzheimer\u2019s disease in older adults 55 and older with signs or symptoms of cognitive decline.
\nCalled the Elecsys\u00ae Phospho-Tau (217P) Plasma (pTau217) blood test, the test was developed in collaboration by pharmaceutical companies Roche and Eli Lilly and Company.
\nMedical News Today spoke with four Alzheimer\u2019s disease experts to find out more about the Elecsys pTau217 blood test \u2014 how it works, how it\u2019s different from the tests already used today for diagnosing Alzheimer\u2019s disease, how people will be able to take the test, and how they predict this new test will change the Alzheimer\u2019s disease diagnostic landscape.
\nWhat is the Elecsys pTau217 test, and how does it work?
\nAccording to Peter Gliebus, MD, chief of neurology and director of cognitive and behavioral neurology at Marcus Neuroscience Institute, a part of Baptist Health South Florida, the Elecsys pTau217 blood test works by detecting phosphorylated tau 217 in blood, one of the earliest and most specific blood indicators of Alzheimer\u2019s.
\n\u201cIt rises early in the disease and remains mostly normal in other neurodegenerative conditions,\u201d Gliebus explained. \u201cAlthough it is a tau marker, blood pTau217 closely correlates with brain amyloid.\u201d
\nLaura Nisenbaum, PhD, interim chief science officer of the Alzheimer\u2019s Drug Discovery Foundation (ADDF), said the Elecsys test measures pTau217 concentration in plasma and uses validated cutoffs to categorize results as positive, intermediate, or negative.
\n\u201cOne of its distinguishing features is that it applies the same cutoffs across both primary and specialty care settings, which matters enormously for consistent, scalable implementation,\u201d Nisenbaum told MNT.
\nHow is this blood test different from those already available?
\nThe Elecsys pTau217 blood test is not the first Alzheimer\u2019s test to be approved by the FDA.
\n\u201cThe FDA cleared the Lumipulse G pTau217\/\u00df-amyloid 1-42 Plasma RatioTrusted Source [test] in May 2025,\u201d Dung Trinh, MD, an internist for MemorialCare Medical Group and chief medical officer of Healthy Brain Clinic in Irvine, CA, told MNT. \u201cThat test measures two biomarkers and calculates a ratio. Roche also received FDA clearance in 2025 for its Elecsys pTau181 test, which is primarily intended to help rule out Alzheimer\u2019s-related amyloid pathology in primary care.\u201d
\nTrinh explained that what distinguishes the new Elecsys pTau217 test is that it is a single-biomarker assay that Roche says supports both rule-in (positive result) and rule-out (negative result) assessment of amyloid pathology, using the same validated cutoffs in primary and specialty care.
\n\u201cThat simplicity could be operationally important because one assay can potentially be used throughout the patient journey rather than requiring different testing strategies in different settings,\u201d he continued.
\nMNT also spoke with Megan Glenn, PsyD, clinical neuropsychologist at the Center for Memory and Healthy Aging at the Hackensack Meridian Neuroscience Institute at Jersey Shore University Medical Center in New Jersey, who said that while we have seen several other blood markers explored over the last few years, many of them capture general brain inflammation or are easily affected by other neurological conditions.
\n\u201cWhat makes this specific tau marker stand out is its strong connection to the exact amyloid plaques that are characteristic of Alzheimer\u2019s disease,\u201d Glenn explained.
\n\u201cWhen compared directly to other options, this marker has consistently proven to be the most accurate at identifying these biological changes. It gives us a much clearer picture of what is happening biologically than previous blood tests could offer. This level of reliability is exactly what we need to confidently use blood testing in a clinical setting.\u201d
\n\u2014 Megan Glenn, PsyD
\nWho will have access to this blood test and where can it be taken?
\nThe Elecsys pTau217 is a standard blood draw, the same kind patients already get for routine cholesterol or blood sugar testing, Nisenbaum explained.
\n\u201cBecause it is designed to run on Roche\u2019s existing labs, it should be accessible through many of the same laboratories that handle routine blood work,\u201d she said. \u201cIn practice, a patient experiencing cognitive symptoms would discuss testing options with their physician, who would order it as part of a broader evaluation.\u201d
\n\u201cThe result, categorized as positive, intermediate, or negative for amyloid pathology, would then be interpreted alongside other clinical information to guide next steps. It is not a test patients can order themselves, and a positive result should always prompt further conversation with a clinician about what it means and what comes next.\u201d
\n\u2014 Laura Nisenbaum, PhD
\nTrinh added that the FDA-cleared intended population is important to note for this test.
\n\u201cThis is for individuals aged 55 and older who are presenting with signs, symptoms, or complaints of cognitive decline,\u201d he said. \u201cIt is not currently cleared as a general screening test for healthy, asymptomatic adults.\u201d
\nHow will this test change the Alzheimer\u2019s diagnostic landscape?
\nGlenn said that the FDA clearance of this new blood test is a massive step forward in making cognitive evaluations more accessible for everyone.
\n\u201cBy using standard laboratory equipment, it brings advanced testing capabilities to a much wider group of patients who might never have had access to specialized brain scans,\u201d she explained. \u201cThe most important thing to remember is that this test supports a careful clinical evaluation and does not replace a comprehensive assessment by a qualified professional.\u201d
\n\u201cThis marks a significant inflection point, not just small news: it is the first FDA-cleared blood test that can both confirm and exclude Alzheimer\u2019s amyloid pathology from a single blood sample, available on lab instruments already in thousands of hospitals,\u201d Gliebus said.
\n\u201cThis is important because approximately 75% of dementia cases remain undiagnosed, mainly due to confirmatory tests like PET scans and spinal taps being expensive, invasive, and limited to specialized centers,\u201d he added.
\n\u201cJust over a year ago, there were no FDA-cleared blood tests for Alzheimer\u2019s \u2014 now there are four,\u201d Nisenbaum commented. \u201cThat is a remarkable shift in a very short period.\u201d
\n\u201cThe broader implication is that blood-based diagnostics are no longer a future promise. They are becoming part of routine clinical practice, and that changes how we think about everything downstream, from trial design to drug development to how patients and families get answers. The diagnostic landscape five years from now will look very different from the one we had just a year ago.\u201d
\n\u2014 Laura Nisenbaum, PhD
\nWhat the Elecsys pTau217 test cannot tell us yet
\nBefore incorporating the Elecsys pTau217 blood test into routine care, Trinh said there are several things he would want to very clearly understand. For example, he would want to see the complete FDA labeling and real-world performance data, not only overall accuracy, but the positive and negative predictive values in the types of patients he actually sees.
\n\u201cPredictive value can change substantially depending on the prevalence of disease in the population being tested,\u201d he explained. \u201cSecond, I would want to know more about the intermediate result group. A test can perform very well overall, but from a clinician\u2019s perspective, the critical operational question is: How many patients fall into the gray zone, and exactly what should we do with them?\u201d
\nTrinh said he would also want clinicians and readers to understand exactly what the test cannot tell us.
\n\u201cRoche specifically states that it is not a stand-alone diagnostic test, and its safety and effectiveness have not been established for predicting who will later develop dementia or for monitoring treatment response,\u201d he explained.
\n\u201cA biomarker can tell us something very important about Alzheimer\u2019s-related pathology, but caring for the patient still requires determining whether that pathology explains the symptoms, what stage of disease the person is in, what other conditions may be contributing, and what treatment or care plan is appropriate.\u201d
\n\u2014 Dung Trinh, MD<\/p>\n","protected":false},"excerpt":{"rendered":"
ISLAMABAD On August 24, 2026, the U.S. FDA cleared a new single-biomarker blood test to help doctors detect signs of Alzheimer\u2019s disease. The test helps doctors determine both rule-in (positive result) and rule-out (negative result) assessment of amyloid pathology, a hallmark of Alzheimer\u2019s disease. The blood test is specifically for older adults 55 and older […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-564635","post","type-post","status-publish","format-standard","category-national"],"yoast_head":"\n