The Elecsys pTau217 blood test, developed by Roche in collaboration with Eli Lilly, received clearance from the U.S. Food and Drug Administration (FDA) for use in assessing the likelihood of Alzheimer’s disease or ruling it out in people aged 55 and older who show signs of cognitive decline. The test measures a single biomarker, phosphorylated tau 217 (pTau217), which is associated with the presence of amyloid deposits in the brain.
According to the description provided, the test does not independently diagnose each case. Rather, it helps physicians estimate the likelihood of amyloid pathology earlier in the diagnostic pathway and identify patients who may need additional evaluation. Roche received the European CE mark for the test in May, before the U.S. clearance.
National Launch Through Two Major Laboratories
Labcorp and Quest Diagnostics said they intend to offer the test in the United States. Labcorp plans to make it available nationwide in the coming months, while Quest will launch it as part of a laboratory testing service called AD-Detect in the fourth quarter. Quest also plans to integrate it into future AD-Detect panels during 2027.
The test was designed to work with Roche’s Cobas laboratory systems, with the aim of supporting rapid implementation and broader access. Roche says that using validated, standardized clinical thresholds can improve consistency in interpreting results between primary care facilities and specialized centers. Labcorp said the test’s performance is comparable to cerebrospinal fluid tests and positron emission tomography (PET) brain imaging, while noting that standardizing measurements across tests and care settings remains an important factor for physicians.
What Changes in Practice?
Assessment of amyloid pathology has largely relied on techniques such as PET imaging or cerebrospinal fluid analysis, both of which are more difficult to access outside specialized centers. A blood test could therefore expand the initial assessment pathway, particularly if it becomes available through national laboratory networks. However, commercial expansion does not eliminate the need to interpret the result within the context of the patient’s condition, and the source does not establish that the test will replace imaging or specialized testing in all cases.
A Market Moving Toward Greater Competition
Roche and Eli Lilly’s clearance comes amid accelerating competition in Alzheimer’s-related blood tests. In May 2025, the FDA cleared Fujirebio’s Lumipulse test, which compares the ratio of pTau217 to beta-amyloid, making it the first laboratory blood-based diagnostic test to help diagnose Alzheimer’s. Labcorp and Quest also began selling internally developed tests for the same biomarkers that year.
In the previous week, the FDA cleared C2N Diagnostics’ PrecivityAD2 test for people aged 40 and older. That test uses mass spectrometry to analyze amyloid ratios and two forms of tau protein. It is expected to become available later in the year, while an internally developed version will continue to be offered. Leerink Partners analysts believe the launches of the C2N and Roche-Lilly tests signal growing momentum and competition, while questions concerning measurement standardization, determining the most appropriate use for each test, and the role of advanced testing in clinical decision-making remain issues that physicians will need to assess in practice.