Diagnostic technology advancements hold promise for a new era for Alzheimer’s screening and monitoring tests that are more accessible and less invasive than traditional methods like PET (Positron Emission Tomography) scans and spinal taps. This paves the way for easier diagnosis of potential Alzheimer’s patients, particularly in a community screening setting.
A breakthrough came in May when the Food and Drug Administration (FDA) issued marketing clearance within the United States (US) for the first blood test for use in diagnosing Alzheimer’s disease: Fujirebio’s Lumipulse G pTau 217/β-Amyloid 1-42 Plasma Ratio. “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,” FDA Commissioner Martin A. Makary in the Agency’s 16 MAY 2025 statement.
How it works
The test measures two proteins in a blood sample and calculates their ratio to determine the likelihood of amyloid plaques in the brain, which strongly correlate with Alzheimer’s. Specifically, two (2) tests of a blood sample are used to detect and measure concentrations of phosphorylated tau 217 (p-tau 217) and beta-amyloid (β-Amyloid)1-42 to detect amyloid plaques associated with Alzheimer’s disease in adult patients. Once the individual concentrations for pTau 217 and β-Amyloid 1-42 have been determined, the company’s Lumipulse G1200 system can be used to automatically calculate a single ratio. This final ratio is the single number used by healthcare providers to help determine the likelihood of amyloid plaques in the patient’s brain.
Intended use and success rate
The test is intended for patients presenting at a specialized care setting with signs and symptoms of cognitive decline. The results must be interpreted in conjunction with other patient clinical information to reduce the risk of false positives and false negatives. During its review, FDA evaluated data from a multi-center clinical study of 499 individual plasma samples from adults who were cognitively impaired and compared the results with amyloid PET scan or CSF test results.
In this clinical study, 91.7% of individuals with Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio positive results had the presence of amyloid plaques by PET scan or CSF test result; and 97.3 % of individuals with negative results had a negative amyloid PET scan or CSF test result. Less than 20% of the 499 patients tested received an indeterminate Lumipulse G pTau217/β-Amyloid 1-42 Plasma Ratio result. “These findings indicate that the new blood test can reliably predict the presence or absence of amyloid pathology associated with Alzheimer’s disease at the time of the test in patients who are cognitively impaired,” FDA concluded, adding the caveat: “The results must be interpreted in conjunction with other patient clinical information.”
REFERENCE: Medical Device and Diagnostic Industry (MD+DI); 16 SEP 2025; Staff (Informa Markets Engineering)