FDA clears blood test to aid evaluation for Alzheimer's disease
FDA Grants Clearance for Blood Test to Assist in Alzheimer's Disease Evaluation
Date: August 21, 2026
Reporter: Matt Miller/WashU Medicine
The Food and Drug Administration (FDA) has officially cleared a pioneering blood test designed to assist in the diagnosis of Alzheimer’s disease. This breakthrough is based on technology originally invented at WashU Medicine.
The test, branded as PrecivityAD2, provides a non-invasive alternative to traditional diagnostic methods. It is capable of identifying amyloid plaque biomarkers with an accuracy rate exceeding 90%.
🔬 Technical Overview: PrecivityAD2
Developed and validated by C2N Diagnostics—a startup originating from WashU—PrecivityAD2 is specifically cleared to help clinicians identify the presence of brain amyloid plaques, a hallmark of Alzheimer's pathology.
Methodology Comparison
While other FDA-cleared blood tests typically rely on immunoassay methods, PrecivityAD2 utilizes high-resolution mass spectrometry. This allows for precise, quantitative measurements of specific biomarkers.
| Feature | PrecivityAD2 | Traditional Diagnostics |
|---|---|---|
| Procedure | Single Blood Draw | |
| Invasiveness | Low | High |
| Technology | High-Res Mass Spectrometry | Imaging / Fluid Analysis |
| Accuracy | High (Gold Standard) |
The Biomarker Chemistry
The test analyzes the specific ratios of amyloid and tau proteins. Using notation, the biomarkers measured include:
- Amyloid Beta: and
- Tau Proteins: and
# Conceptual logic for biomarker evaluation
def evaluate_alzheimers_risk(amyloid_ratio, tau_levels):
if amyloid_ratio < threshold and tau_levels > threshold:
return "Positive for Amyloid Pathology"
else:
return "Negative/Inconclusive"
🧬 The Scientific Foundation
The core technology was spearheaded by a team at WashU Medicine, co-led by:
- Dr. Randall J. Bateman (Joanne Knight Distinguished Professor of Neurology)
- Dr. David M. Holtzman (Morriss Distinguished Professor in the Department of Neurology)
The Path to Commercialization
- 2007: C2N Diagnostics is co-founded by Bateman, Holtzman, and others.
- Licensing: C2N acquired exclusive rights to patented technologies from the Bateman and Holtzman labs.
- Optimization: The startup refined the assays to create the commercial tests used today.
The SILK Approach
The research was grounded in stable isotope-linked kinetics (SILK). This method allowed researchers to study how amyloid-beta is produced and cleared within the brain and cerebrospinal fluid, providing the scientific bedrock for blood-based testing.
🏥 Clinical Impact and Patient Benefits
Early detection is critical because new treatments that slow neurodegeneration are most effective when administered as early as possible.
"The PrecivityAD2 test provides an accurate and reliable way to detect the presence of brain amyloid plaques associated with Alzheimer’s disease pathology based on a single blood draw," stated Dr. Bateman. "With faster diagnosis, patients can receive earlier treatment, when treatments are most effective."
Why FDA Clearance Matters
While the test was previously available for mild cognitive symptoms, official clearance provides several advantages:
- Broadened Market: Can be marketed to a wider array of clinicians and health systems.
- Quality Assurance: Provides a standardized seal of approval for medical institutions.
- Financial Accessibility: Facilitates insurance coverage, making the test more affordable.
🚀 Looking Forward
The transition from invasive spinal taps to simple blood draws represents a paradigm shift in neurology.
"Achieving FDA clearance of the PrecivityAD2 blood test is a key milestone in our mission to transform the diagnosis and management of Alzheimer’s disease on a path toward finding a cure," noted Dr. Holtzman.
Summary of Resources
- Institution: WashU Medicine
- Company: C2N Diagnostics
- Test Name:
PrecivityAD2 - Key Goal: Early, accurate, and accessible diagnosis.
