FDA Approves First Alzheimer's Blood Test for Primary Care Use

Roche and Eli Lilly have secured FDA approval for Elecsys pTau181, the first blood-based test for Alzheimer's disease assessment approved for use in primary care settings. This landmark decision, announced on October 14, 2025, marks a significant advancement in the early detection and management of Alzheimer's disease.

Elecsys pTau181: A Game-Changer in Alzheimer's Diagnostics

The Elecsys pTau181 test is designed for patients 55 years and older who exhibit signs or report symptoms of cognitive decline. By measuring blood levels of the phosphorylated Tau (pTau) 181 protein, the test aids in ruling out Alzheimer's disease-related pathology. However, Roche and Lilly emphasize that results should be interpreted alongside other clinical information.

Data from over 300 patients supported the FDA's decision, demonstrating Elecsys' impressive 97.9% negative predictive value in ruling out Alzheimer's pathology. This high accuracy positions the test as a valuable tool for primary care physicians in guiding appropriate referrals and allowing neurologists to focus on patients most likely to require advanced evaluation and treatment.

Potential Impact on Alzheimer's Treatment Landscape

The approval of Elecsys could have far-reaching implications for the uptake of currently approved Alzheimer's therapies. Biogen CEO Chris Viehbacher recently highlighted the potential of biomarker-based tests like Elecsys to "remove some of the bottlenecks" in treatment uptake, particularly for drugs such as Biogen's Eisai-partnered Leqembi.

This development comes amidst a series of regulatory wins in the Alzheimer's space. Last month, Biogen and Eisai received approval for a subcutaneous version of Leqembi, branded as Leqembi Iqlik, for maintenance therapy. Additionally, Eli Lilly's anti-amyloid therapy Kisunla secured a label expansion in July for a more gradual dosing schedule, potentially reducing the risk of amyloid-related imaging abnormalities.

Broadening Access to Alzheimer's Diagnostics

While Elecsys is not the first FDA-approved blood test for Alzheimer's – that distinction belongs to Fujirebio Diagnostics' Lumipulse G pTau217/β-Amyloid 1-42 Plasma Ratio – it is the first to be approved for use in primary care settings. This broader availability is expected to significantly increase access to minimally invasive testing, potentially leading to earlier interventions and improved patient outcomes.

The approval of Elecsys represents a collaborative effort between Roche and Eli Lilly, stemming from their March 2023 partnership aimed at earlier Alzheimer's detection. As the pharmaceutical industry continues to make strides in Alzheimer's research and treatment, tools like Elecsys may play a crucial role in shaping the future of dementia care and management.