Elecsys pTau181 Blood Test Gains European Approval for Alzheimer Disease Diagnosis

Matt Sause

According to a new announcement, Roche’s Elecsys pTau181 test, a blood test geared to rule out Alzheimer disease (AD) diagnosis from other cognitive declines, has gained CE Mark, opening access for those who live in the European Union.¹

The blood test, approved in the U.S. in 2022, is an automated, in-vitro diagnostic assay that measures phosphorylated tau (p-Tau)181, a key biomarker of amyloid pathology and one of the two hallmark proteinopathies in AD. It serves as a rule-out tool: a negative result reliably indicates no amyloid pathology, reducing the need for PET scans or lumbar punctures.

Through this simple blood test, clinicians may better triage and manage cognitive declines earlier. To date, the test has been shown to be effectively implemented across care settings, including primary care, where patients often first present with cognitive concerns. A positive test can lead to further testing and earlier identification of AD pathology, which may be critical for accessing new treatments and helping patients make informed decisions about future care.

"The burden of Alzheimer’s disease on society and healthcare systems is increasing as the world’s population ages," Matt Sause, chief executive officer at Roche, said in a statement.¹ "With Elecsys pTau181, doctors can give patients and their caregivers the clarity they need when establishing the cause of cognitive decline. By enabling an earlier and less invasive diagnosis, this test has the potential to improve patient outcomes and decrease costs for healthcare systems worldwide."

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The decision to approve the blood test was based on a prospective, multicenter study in which the modality was shown to rule out AD with a high negative predictive value (NPV) of 93.8% based on a 22.5% prevalence of amyloid positivity according to PET scans, with 83.6% sensitivity. The study, a first-of-its-kind comprising 787 patients across the U.S., Europe, and Australia, also showed that the rule out performance of the test was only minimally impacted by the patients’ age, gender, body mass index, or impaired kidney function.

The European Union’s decision to approve the test arrives at a pivotal moment, as the need for robust AD screening and diagnostic tools has never been more urgent. In recent years, the advent of anti-amyloid therapies—shown to be consistently more effective when administered in the earliest stages of the disease—has reshaped the clinical conversation around how to approach AD treatment. To date, two FDA-approved therapies in this class—lecanemab (Leqembi; Eisai) and donanemab (Kisunla; Eli Lilly)—entered the market in 2023 and 2024, respectively, marking a new era in disease-modifying care.

In 2023, the FDA granted 510(k) clearance to Roche for its Elecsys assays–including beta-amyloid 1-42 CSF II (Abeta42) and total tau (tTau) assay. Similar to the ptau181 test, these tools are intended to be used with other clinical diagnostic evaluations during the diagnosis process for patients with potential AD, and thus, do not establish a diagnosis of AD. The combination of all 3 assays–tTau/Abeta42, Abeta42, and pTau181–are reflective of the main AD pathologies and help clinicians more completely define the disease biologically, facilitating a diagnosis of inclusion.^2,3

REFERENCES
1. Roche receives CE Mark for minimally invasive blood test to help rule out Alzheimer’s disease. July 23, 2025. Accessed July 23, 2025. https://www.globenewswire.com/news-release/2025/07/23/3119980/0/en/Roche-receives-CE-Mark-for-minimally-invasive-blood-test-to-help-rule-out-Alzheimer-s-disease.html
2. Roche receives FDA clearance for additional Alzheimer’s disease cerebrospinal fluid (CSF) assays, supporting timely diagnosis and treatment decision-making. News release. June 27, 2023. Accessed July 23, 2025.
3. Roche Alzheimer’s disease Cerebrospinal Fluid (CSF) assays receive FDA clearance, supporting more accurate and timely diagnosis. News release. Roche. July 19, 2022. Accessed July 23, 2025. https://diagnostics.roche.com/us/en/news-listing/2022/roche-alzheimers-disease-cerebrospinal-fluid-assays-receive-fda-clearance.html