FDA Clears Lumipulse Plasma Ratio as First Blood Test for Diagnosing Alzheimer Disease

Martin A. Makary, MD, MPH, FDA Commissioner

According to a new announcement, the FDA has cleared Fujirebio’s Lumipulse G p-tau217/ß-Amyloid 1-42 Plasma Ratio, a diagnostic blood test, for the early detection of amyloid plaques associated with Alzheimer disease (AD) in adults aged 55 and older. With the decision, it becomes the first such in vivo blood test used in the diagnosis of AD.¹

The test operates on the Lumipulse G platform, a fully automated system that uses chemiluminescent enzyme immunoassay technology to quantify biomarkers with high sensitivity and precision. The p-tau217 protein, associated with neurofibrillary tangles in AD, and ß-Amyloid 1-42, which forms amyloid plaques, are measured in plasma using the Lumipulse G p-tau217/ß-Amyloid 1-42 Plasma Ratio to distinguish amyloid-positive individuals from amyloid-negative ones, giving patients a non-invasive alternative for early AD detection.

"Alzheimer disease impacts too many people, more than breast cancer and prostate cancer combine," Martin A. Makary, MD, MPH, FDA Commissioner, wrote in a statement.¹ "Knowing that 10% of people aged 65 and older have Alzheimer's, and that by 2050 that number is expected to double, I am hopeful that new medical products such as this one will help patients."

A study of nearly 500 participants with mild cognitive impairment (MCI), published in Fluids Barriers CNS in 2025, was one of the main reasons for the decision. In this trial, investigators collected data on 6 different biomarkers including, volumetric MRI, PET-FDG, EEG for connectivity analysis, cerebrospinal fluid (CSF) and blood including apolipoprotein (APOE) genotyping. Biomarkers were collected after harmonization meetings for procedure standardization; moreover, their final evaluation was carried out in centralized expert centers highly specialized for each biomarker.²

Using a fully automated chemiluminescence enzyme immunoassay and the Lumipulse G600II instrument, investigators observed statistically significant positive correlations between CSF and plasma Aß42, Aß42/40 ratio, and ptau181. More notably, 91.7% of those with a positive result on the test demonstrated the presence of amyloid plaques by PET scan or CSF test result. In addition, 97.3% of individuals with negative results had a negative amyloid PET scan or CSF test result.

READ MORE: Plasma GFAP May Enrich Patient Selection, Reduce PET Scans Required for Alzheimer Trials

In the study, investigators demonstrated that ptau217 diagnostic performance is increased when also tau pathology is taken into account, showing a robust area under the curve (AUC) of 0.911 (95% CI, 0.875-0.947) for the comparison between amyloid-positive/tau-positive and amyloid-negative/tau-negative. Moreover, Aß42 and Aß42/Aß40 plasma levels were lower in amyloid-positive/tau-negative patients compared with amyloid-negative/tau-negative and amyloid-negative/tau-positive groups, and ptau181 and ptau217 plasma levels were higher in amyloid-positive/tau-positive patients compared with amyloid-positive/tau-negative individuals.

The Lumipulse G p-tau217/ß-Amyloid 1-42 Plasma Ratio, which previously received breakthrough device designation, was reviewed through the 510(k) premarket notification pathway. A 510(k) notification is a premarket submission to the FDA that shows a new device is substantially equivalent to an existing legally marketed device. The FDA determined that the Lumipulse G pTau217/β-Amyloid 1-42 Plasma Ratio is substantially equivalent to the previously authorized Lumipulse G β-amyloid Ratio (1-42/1-40) test, which uses CSF samples.

"Nearly 7 million Americans are living with Alzheimer disease and this number is projected to rise to nearly 13 million," Michelle Tarver, MD, PhD, director, Center for Devices and Radiological Health, said in a statement.¹ "Today’s clearance is an important step for Alzheimer disease diagnosis, making it easier and potentially more accessible for U.S. patients earlier in the disease."

The Lumipulse G ß-amyloid Ratio (1-42/1-40) test, another diagnostic tool indicated for early detected of amyloid plaques in AD, was previously approved by the FDA in mid-2022. The test, intended to measure the ratio of Aß1-42 and Aß1-40, was reviewed through the de novo premarket review pathway. Because there is a possibility that a positive result could be seen in patients with other types of neurologic conditions as well as cognitively healthy elders, the test is not intended as a screening or stand-alone diagnostic assay. The FDA noted that the results of the test should be interpreted in conjunction with other patient clinical information.³

REFERENCES
1. FDA Clears First Blood Test Used in Diagnosing Alzheimer’s Disease. News release. FDA. May 16, 2025. Accessed May 16, 2025. https://www.fda.gov/news-events/press-announcements/fda-clears-first-blood-test-used-diagnosing-alzheimers-disease
2. Catania M, Battipaglia C, Perego A, et al. Exploring the ability of plasma pTau217, pTau181 and beta-amyloid in mirroring cerebrospinal fluid biomarker profile of Mild Cognitive Impairment by the fully automated Lumipulse® platform. Fluids Barriers CNS. 2025;22:9. doi:10.1186/s12987-025-00620-5
3. FDA permits marketing for new test to improve diagnosis of Alzheimer’s disease. News release. FDA. May 4, 2022. Accessed May 16, 2025. https://www.fda.gov/news-events/press-announcements/fda-permits-marketing-new-test-improve-diagnosis-alzheimers-disease?utm_campaign=FDA+Permits+Marketing+for+New+Test+to+Improve+Diagnosis+of+Alzhe&utm_medium=email&utm_source=govdelivery