FDA Clears Roche's Single-Biomarker Elecsys pTau217 Blood Test for Alzheimer Disease

The FDA has cleared Elecsys pTau217, a blood-based immunoassay from Roche developed in collaboration with Eli Lilly, to aid clinicians in identifying amyloid pathology associated with Alzheimer disease (AD) in adults 55 and older with signs, symptoms, or complaints of cognitive decline. Roche describes it as the first and only FDA-cleared, single-biomarker blood test that supports both rule-in and rule-out assessment of amyloid pathology using the same validated cutoffs across primary and specialty care.¹

"FDA clearance of Elecsys pTau217 marks an important milestone in Alzheimer's disease diagnosis and underscores Roche's continued leadership in advancing innovative solutions that can help patients get answers sooner," Dan Malarek, president and CEO of Roche Diagnostics North America, said in a statement.¹

What the test measures

Elecsys pTau217 quantifies plasma concentrations of tau phosphorylated at threonine 217, a biomarker whose elevation is strongly associated with amyloid pathology, rather than functioning as a general marker of neuronal injury. The assay is not intended as a stand-alone diagnostic; results are meant to be interpreted alongside clinical history, cognitive assessment, and other diagnostic information as part of the broader AD workup.¹

The test produces 3 result categories: positive (high likelihood of amyloid pathology), negative (low likelihood, prompting evaluation of other causes of cognitive decline), and intermediate (indeterminate, generally warranting confirmatory testing). Roche has not established the assay's safety or effectiveness for predicting future dementia onset, for use in other neurologic conditions, or for monitoring therapeutic response.

Validation data

The clearance draws on a study published in Alzheimer's & Dementia in January 2026 that evaluated the assay across 5 cohorts totaling 2,148 individuals, comparing plasma pTau217 against amyloid PET. Among cognitively impaired participants, amyloid-positive individuals had a mean pTau217 concentration of 0.835 pg/mL, compared with 0.361 pg/mL in amyloid-negative participants, corresponding to an area under the ROC curve of 0.878 (95% CI, 0.840-0.915).²

Among cognitively unimpaired participants, the AUC was 0.907 (95% CI, 0.885-0.929).² A low-concentration cutoff also demonstrated strong negative predictive value, supporting the assay's use as a rule-out tool.

"For millions of families navigating the uncertainty of Alzheimer's disease, a timely diagnosis is the first and most critical step toward meaningful care," Carole Ho, MD, executive vice president and president of Lilly Neuroscience, said in a statement.¹

How it differs from other cleared assays

Elecsys pTau217 differs structurally from its main cleared competitor, Fujirebio's Lumipulse G pTau217/β-amyloid 1-42 Plasma Ratio, cleared in May 2025, which calculates a ratio between 2 analytes rather than relying on a single biomarker.³ Roche's single-analyte approach is designed to let one assay generate a rule-in, intermediate, or rule-out result without a second biomarker.¹

The test runs on Roche's cobas e 402 and cobas e 801 immunoassay systems, with an analytical run time of roughly 18 minutes; more than 4,500 compatible cobas instruments are already installed across US laboratories, which Roche says positions the assay for rapid, broad implementation without new hardware.

Availability

Both Labcorp and Quest Diagnostics announced plans to offer the FDA-cleared assay the same day as the clearance.⁴ Quest said it will introduce an AD-Detect-branded laboratory service based on the test to physicians and clinical trial collaborators in the fourth quarter of 2026, and plans to incorporate it into future AD-Detect panels in 2027.

Separately, Quest also announced a new multi-biomarker AD-Detect panel combining amyloid beta 42/40, pTau217, and APOE genotype, which the company said achieved a 10% indeterminate rate in recent research, below the 15%-20% rate cited by the Global CEO Initiative on Alzheimer's Disease for a typical clinical population.⁴

"As one of the pioneers in this field, Quest is constantly looking to add new innovations, both our own and from our collaborators, to our extensive AD-Detect portfolio so that physicians and patients can make the most informed care decisions," Michael K. Racke, MD, senior medical director of neurology at Quest Diagnostics, said in a statement.⁴

Clinical context

Traditional methods for assessing amyloid pathology, including amyloid PET and cerebrospinal fluid testing, can be costly, invasive, and difficult to access outside specialty centers. An estimated 75% of people living with dementia remain undiagnosed, and those who are diagnosed often experience years of uncertainty after symptoms first appear.¹

"Advances in blood-based biomarkers have the potential to transform the diagnostic pathway by expanding access to evaluation for Alzheimer's across a variety of care settings," Jared R. Brosch, MD, a neurologist at Indiana University Health who was not involved in developing the test, said in a statement.¹

Part of a broader diagnostics portfolio

Elecsys pTau217 adds to a growing line of Roche AD diagnostics, including Elecsys pTau181, cleared by the FDA in October 2025 as the first blood-based biomarker test available for primary care to help rule out amyloid pathology (97.9% negative predictive value in a 312-participant study), and the CSF-based Elecsys beta-amyloid 1-42 and total-tau assays, cleared in 2023.^5,6 Roche's neurology diagnostics portfolio also extends beyond AD; its Elecsys neurofilament light chain test received CE mark approval in April 2026 for monitoring neuroinflammation in relapsing-remitting multiple sclerosis.⁷

REFERENCES
1. Roche receives FDA clearance for Elecsys® pTau217, advancing Alzheimer's disease assessment across primary and specialty care. News release. Roche Diagnostics. August 24, 2026. Accessed August 24, 2026. https://www.prnewswire.com/news-releases/roche-receives-fda-clearance-for-elecsys-ptau217-advancing-alzheimers-disease-assessment-across-primary-and-specialty-care-302857619.html
2. Hibar DP, Bauer A, Rabe C, et al. Elecsys pTau217 plasma immunoassay detection of amyloid pathology in clinical cohorts. Alzheimers Dement. 2026. doi:10.1002/alz.71009
3. Fujirebio Receives Marketing Clearance for Lumipulse® G pTau 217/β-Amyloid 1-42 Plasma Ratio In-Vitro Diagnostic Test. News release. Fujirebio Diagnostics, Inc. May 16, 2025. Accessed August 24, 2026. https://www.fujirebio.com/en-us/news-events/fujirebio-receives-marketing-clearance-for-lumipulser-g-ptau-217bamyloid-142-plasma-0
4. Quest Diagnostics to Offer FDA-Cleared Roche pTau217 Blood Test to Assess Alzheimer's Disease Pathology. News release. Quest Diagnostics. August 24, 2026. Accessed August 24, 2026. https://www.prnewswire.com/news-releases/quest-diagnostics-to-offer-fda-cleared-roche-ptau217-blood-test-to-assess-alzheimers-disease-pathology-302858247.html
5. Roche's Elecsys® pTau181 becomes the only FDA-cleared blood test for use in primary care to rule out Alzheimer's-related amyloid pathology. News release. Roche. October 13, 2025. Accessed August 24, 2026. https://diagnostics.roche.com/us/en/news-listing/2025/fda-cleared-ptau181-alzheimers-blood-test.html
6. Roche receives FDA clearance for additional Alzheimer's disease cerebrospinal fluid (CSF) assays, supporting timely diagnosis and treatment decision-making. News release. Roche. June 27, 2023. Accessed August 24, 2026.
7. Roche receives CE mark for new Elecsys NfL blood test to detect neuroinflammation in multiple sclerosis. News release. Roche. April 13, 2026. Accessed August 24, 2026. https://www.roche.com/media/releases/med-cor-2026-04-13