A groundbreaking study led by the Foundation for the National Institutes of Health (FNIH) Biomarkers Consortium has validated that certain commercial blood tests are accurate enough for clinical use in detecting Alzheimer's disease, potentially eliminating the need for invasive spinal taps and expensive brain scans in many patients with cognitive impairment.
The head-to-head comparison study, presented at the Alzheimer's Association International Conference (AAIC) in Philadelphia, evaluated commercially available tests from six major developers: ALZpath, C2N Diagnostics, Fujirebio Diagnostics, Janssen, Quanterix, and Roche Diagnostics. Using blood samples from the Alzheimer's Disease Neuroimaging Initiative (ADNI), researchers assessed the ability of these tests to accurately detect amyloid plaques and tau tangles, brain volume changes, and clinical dementia symptoms.
Key Findings on Test Accuracy
The study confirmed that some blood tests demonstrate accuracy similar to established cerebrospinal fluid tests in determining the presence of amyloid plaques as measured by positron emission tomography (PET) scans. This represents a significant advancement in Alzheimer's diagnostics, as cerebrospinal fluid testing requires an invasive spinal tap procedure.
"Many Alzheimer's blood tests are now clinically available. Some are highly accurate, while others are little better than flipping a coin. Doctors need to know which tests can be trusted," said Suzanne Schindler, MD, PhD, a clinical neurologist and the Fluid Biomarker Core Leader at Washington University School of Medicine in St. Louis, and a member of the FNIH project team.
P-tau217 Emerges as Leading Biomarker
The research provided further confirmation that blood tests measuring levels of the protein p-tau217 are the most accurate in determining both the presence and amount of amyloid plaques in the brain. This finding reinforces the clinical utility of p-tau217 as a reliable biomarker for Alzheimer's disease detection.
Clinical and Research Implications
The validation of these blood tests addresses a critical need in Alzheimer's care, particularly given recent approvals of new anti-amyloid drugs and the numerous treatments currently in clinical trials. "The recent approvals of new anti-amyloid drugs—and the many treatments being studied in clinical trials—underscore the pressing need for more accessible, less invasive testing for early detection of Alzheimer's," said Julie Gerberding, MD, MPH, President and CEO of the FNIH.
Beyond clinical diagnosis, these blood tests could significantly accelerate drug development by helping researchers select optimal participants for clinical trials. The tests also demonstrated capability in detecting low levels of brain amyloid in people without cognitive impairment, opening possibilities for earlier intervention strategies.
Future Research Directions
The FNIH project team is conducting additional analyses to evaluate how well these blood tests can predict Alzheimer's disease progression over time, including the likelihood of presymptomatic individuals eventually developing cognitive symptoms. This research aims to determine whether certain treatments may prevent or slow cognitive decline in patients with early Alzheimer's brain changes.
The comprehensive dataset generated by this study is freely available to the scientific community through ADNI, enabling researchers to further investigate test performance and explore additional scientific questions, including the effects of age, sex, genetics, medical conditions, race, and social determinants of health on amyloid pathology.
Widespread Clinical Impact
The widespread clinical adoption of validated blood tests could lead to more accurate diagnoses of people with cognitive impairment and more efficiently identify patients who may benefit from Alzheimer's treatments. This development represents a significant step toward making Alzheimer's diagnosis more accessible and less burdensome for patients while maintaining diagnostic accuracy.
