The U.S. Food and Drug Administration on Monday (August 24) authorized the Elecsys Phospho-Tau (217P) plasma test (pTau217), developed through a collaboration between Roche Holding Ltd and Eli Lilly. The test is intended for individuals aged 55 and older who are exhibiting signs, symptoms, or complaints of cognitive decline, serving as an aid in determining the presence or absence of amyloid pathology associated with Alzheimer's disease. Results are categorized as positive, intermediate, or negative, and must be interpreted alongside other clinical information—the test is not a standalone diagnostic tool. Pricing has yet to be announced.
Roche Holding Ltd stated that this is currently the only FDA-cleared blood test that relies on a single biomarker, employs the same validated cutoff values across both primary and specialty care settings, and simultaneously supports both "rule-in" and "rule-out" assessments of amyloid pathology. The test measures phosphorylated tau 217 in plasma. Higher levels suggest a greater likelihood that amyloid pathology is present, while lower levels indicate it is more likely absent. Intermediate results warrant further evaluation.
Dan Malarek, President and CEO of Roche Diagnostics North America, commented that the clearance brings the assessment closer to the front lines of patient care. Carol Ho, President of Neuroscience at Eli Lilly, noted that the collaboration's goal is to deliver the same test into both primary care—where most cognitive complaints first surface—and specialty clinics. The intended use and limitations are clearly outlined in the label, restricting application to those aged 55 and older with manifestations of cognitive decline. Roche Holding Ltd explicitly states that safety and efficacy have not been established for predicting the onset of dementia or other neurological diseases, nor for monitoring the effects of therapeutic products. Results must be combined with other diagnostic tools and clinical information.
Richard Isaacson, Director of Research at the Florida Institute for Neurodegenerative Diseases, told CNN that while the negative predictive value is sufficient, the positive predictive value is not ideal. False positives, intermediate classifications, and variables such as sample handling, kidney disease, or viral infections can complicate interpretation. He advocates for using a panel of tests rather than a single "Alzheimer's blood test." The traditional methods for confirming amyloid pathology—PET imaging or cerebrospinal fluid analysis—are costly, invasive, and not readily accessible outside of specialty centers.
Citing materials from the international Alzheimer's Association, Roche Holding Ltd noted that approximately 75% of dementia patients worldwide remain undiagnosed, and it commonly takes about 3.5 years from symptom onset to a confirmed diagnosis. The test is designed to run on the more than 4,500 installed Roche Holding Ltd cobas laboratory instruments in the United States, meaning laboratories do not need to purchase additional equipment. Roche Holding Ltd reported that evaluations show high concordance between this test and amyloid PET imaging in the population aged 55 and older with cognitive complaints. Specific sensitivity and specificity figures were not detailed in the press release.
Labcorp and Quest Diagnostics announced on Monday that they will offer the test through their respective networks. Quest stated it will launch a laboratory service branded as AD-Detect, based on this FDA-cleared reagent, to physicians and clinical trial partners across the U.S. in the fourth quarter of 2026, with plans to incorporate the reagent into future combination panels by 2027. Quest also announced it will introduce its own multi-marker laboratory-developed test at the end of this month, which falls outside the scope of this FDA clearance. The test received European CE marking in May and went on sale in Europe last month. Roche Holding Ltd has not disclosed U.S. pricing.
This marks the fourth FDA clearance for a blood test of its kind. In May 2025, Fujirebio's Lumipulse became the first FDA-approved blood test to aid in assessing Alzheimer's disease. In October of the same year, the Elecsys pTau181 from Roche Holding Ltd and Eli Lilly was cleared, primarily for ruling out amyloid pathology in primary care. Last week, C2N Diagnostics' PrecivityAD2 was authorized, with applicability extending to individuals as young as 40. Notably, pTau217 and pTau181 measure different phosphorylation sites.
Dr. Jared Brosch, a neurologist at Indiana University Health, remarked that while PET and cerebrospinal fluid tests can confirm amyloid pathology, their high cost and invasive nature make them inaccessible to many patients. Blood-based biomarkers expand assessment to a broader range of clinical settings. Roche Holding Ltd's pipeline also includes trontinemab, an amyloid antibody designed for brain delivery (in two Phase III trials), and nivegacetor, an oral gamma-secretase modulator (in Phase II). These drug programs are separate from the test clearance.
The test has been cleared for integration into existing U.S. laboratory workflows. Quest's branded service is slated to be available to physicians in the fourth quarter of 2026. The company has not provided a timeline for pricing, insurance reimbursement pathways, or how intermediate results will be managed in routine outpatient practice. The handling of intermediate results—whether to refer for further evaluation or proceed directly to anti-amyloid therapy assessment—remains at the discretion of individual healthcare institutions and is outside the scope of this label.