FDA approves blood test for the diagnosis of Alzheimer’s Disease

Alzheimer’s disease is a progressive neurodegenerative disorder that affects the brain, gradually impairing memory, reasoning, and behaviour. The disease is marked by the accumulation of abnormal protein deposits in the brain, specifically amyloid plaques and tau tangles. These deposits disrupt neural function and ultimately lead to brain cell death. Over time, individuals lose the ability to carry out daily tasks and experience significant personality and behavioural changes. With age being the biggest risk factor, Alzheimer’s typically affects individuals aged 65 and older (1).

Alzheimer’s disease is the most common cause of dementia, contributing to 60–70% of cases in older adults (2). Recent estimates indicate that approximately 7.4% (8.8 million) of Indians aged 60 and above are affected by dementia (3). 

Despite significant research progress, there is no cure for Alzheimer’s disease (4). Management strategies focus on slowing cognitive decline and maintaining quality of life for as long as possible. Accurate and timely diagnosis remains a major challenge, especially in the early stages when intervention may be most beneficial (5).

Importance of Early Diagnosis

Early diagnosis plays a pivotal role in the management of Alzheimer’s disease. It enables patients and caregivers to make informed decisions about future care, initiate appropriate therapies sooner, and participate in clinical trials during early disease stages. Clinically, early identification can help distinguish Alzheimer’s from other forms of cognitive impairment or reversible conditions. Furthermore, from a healthcare systems perspective, timely diagnosis supports better resource allocation, multidisciplinary care planning, and more effective disease management (6).

Traditionally, the presence of amyloid plaques, which are a hallmark of Alzheimer’s pathology, has been confirmed using PET imaging or cerebrospinal fluid (CSF) analysis through lumbar puncture. These methods, however, are expensive, invasive, or not easily accessible in many clinical settings. The need for a simpler and more patient-friendly diagnostic tool has driven ongoing research into blood-based biomarkers (7).

FDA Clears First Blood-Based Diagnostic Test

On May 16, 2025, the U.S. Food and Drug Administration (FDA) cleared the first blood test designed to assist in the diagnosis of Alzheimer’s disease. The test, known as the Lumipulse G pTau217/β-Amyloid 1-42 Plasma Ratio, was developed by Fujirebio Diagnostics, Inc. It is intended for use in adults aged 55 years and older who exhibit symptoms of cognitive decline and are being evaluated in a specialized care setting. By offering a blood-based method to assess amyloid plaque status, the test provides a less invasive, more accessible alternative to existing diagnostic pathways (8).

The Lumipulse test measures the levels of two proteins in blood: phosphorylated tau 217 and beta-amyloid 1-42, and calculates their ratio. This ratio is known to correlate with the presence or absence of amyloid plaques in the brain. The test is not intended as a screening tool and should not be used as a standalone diagnostic. Instead, it is designed to support clinical decision-making when combined with patient history and other assessments (8).

Clinical Evidence

The FDA’s clearance was based on data from a multicenter clinical study that evaluated 499 plasma samples from individuals with cognitive impairment. These samples were analyzed using the Lumipulse test and compared against amyloid PET scans or CSF test results. The study demonstrated that 91.7% of individuals with Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio positive results had the presence of amyloid plaques identified by PET scan or CSF test result. Around 97.3 % of individuals with negative results had a negative amyloid PET scan or CSF test result (8).

Key Findings

These findings support the test’s accuracy in identifying Alzheimer’s-related changes. However, as with any diagnostic tool, there is a risk of false positives or false negatives. Incorrect results could lead to inappropriate treatment decisions or delayed care. The FDA has emphasized that the test results must be interpreted alongside clinical evaluations and patient history (8).

The Lumipulse G pTau217/β-Amyloid 1-42 Plasma Ratio test was reviewed through the FDA’s 510(k) pathway, indicating that it is substantially equivalent to a previously approved CSF-based biomarker test. It was also granted Breakthrough Device Designation, which is reserved for technologies that offer a significant advantage in the diagnosis or treatment of potentially fatal conditions (8).

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About the Author

Ms. Hima Saxena is a medical writer and editor with a Master’s in Pharmaceutics and a strong background in medical communications. She creates clear, evidence-based content that supports healthcare professionals and empowers patients. Hima collaborates with pharmaceutical and healthcare clients to deliver accurate, impactful content across diverse therapeutic areas, bridging scientific integrity with accessible communication.

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References

1. What Is Alzheimer's Disease? Available at: https://www.nia.nih.gov/health/what-alzheimers-disease. Accessed June 4, 2025.

2. Dementia. Available at: https://www.who.int/news-room/fact-sheets/detail/dementia. Accessed June 4, 2025.

3. Lee J, Meijer E, Langa KM, et al. Prevalence of dementia in India: National and state estimates from a nationwide study. Alzheimers Dement. 2023 Jan 13;19(7):2898–2912. 

4. Kumar A, Sidhu J, Lui F, et al. Alzheimer Disease. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Feb 12. Available from: https://www.ncbi.nlm.nih.gov/books/NBK499922/

5. Safiri S, Jolfayi AG, Fazlollahi A, et al. Alzheimer's disease: a comprehensive review of epidemiology, risk factors, symptoms, diagnosis, management, caregiving, advanced treatments and associated challenges. Front Med (Lausanne). 2024 Dec 16;11:1474043. 

6. Rasmussen J, Langerman H. Alzheimer’s disease – why we need early diagnosis. Degener Neurol Neuromuscul Dis. 2019 Dec 24;9:123–130. 

7. Schöll M, Verberk IMW, del Campo M, et al. Challenges in the practical implementation of blood biomarkers for Alzheimer’s disease. Lancet Healthy Longev. 2024 Oct;5(10):100630. 

8. FDA News Release. FDA Clears First Blood Test Used in Diagnosing Alzheimer’s Disease. Available at: https://www.fda.gov/news-events/press-announcements/fda-clears-first-blood-test-used-diagnosing-alzheimers-disease. Accessed on 04 June 2025.

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