Blood test eliminates need for invasive procedures
The FDA cleared the Lumipulse G pTau217/β-Amyloid 1-42 Plasma Ratio assay for commercial use, allowing doctors to diagnose Alzheimer's disease with a simple blood draw. The test measures the ratio of phosphorylated tau 217 to beta-amyloid 1-42 in the blood, which correlates with the presence of amyloid plaques in the brain — a hallmark of Alzheimer's. Previously, confirming an Alzheimer's diagnosis required either a costly PET scan or a lumbar puncture to test cerebrospinal fluid.
97.3% accuracy in ruling out disease
In clinical studies, 91.7% of patients with positive test results had confirmed amyloid plaques on PET scans or CSF tests, while 97.3% of those with negative results had no detectable plaques. The high negative predictive value means primary care physicians can confidently rule out Alzheimer's disease in patients showing cognitive symptoms, reducing the need for specialist referrals and expensive imaging. The test is approved for patients aged 55 and older with signs of cognitive decline.
New era for dementia diagnostics in primary care
The approval opens the door to screening over one million Americans in the first year alone, according to projections. Alzheimer's disease affects one in nine older adults in the U.S., and early diagnosis is considered key to better outcomes. The test is expected to be widely adopted in primary care settings, potentially reducing diagnosis delays that currently average two to three years from symptom onset. Roche and Lilly are already scaling up production to meet anticipated demand.