The U.S. FDA has authorized the marketing of PrecivityAD2, an early Alzheimer's disease blood test based on original technology developed at Washington University School of Medicine in St. Louis (WashU Medicine). Development and validation were handled by C2N Diagnostics, a WashU spinoff company.
It determines the presence or absence of amyloid plaques in the brain with a single blood draw. Unlike previously approved blood tests that use immunoassays, this test uses high-resolution mass spectrometry to quantitatively measure biomarkers.
The targets measured are the ratio of amyloid (Aβ42/Aβ40) and two types of tau proteins (p-tau217, total tau217).
Prior research showed an accuracy of over 90% in diagnosing amyloid pathology and demonstrated performance comparable to lumbar puncture (cerebrospinal fluid test) or brain imaging even in patients with mild symptoms.
This is significant because recently approved treatments for slowing Alzheimer's progression are most effective when started early. FDA authorization will expand sales to hospitals and medical systems, increasing the likelihood of insurance coverage and improving accessibility and cost burden.
The work builds on research by Randall J. Bateman, and David M. Holtzman, professors in the Department of Neurology at WashU. The two pioneered the SILK (stable isotope-linked kinetics) technique for tracking amyloid-beta production and clearance, and co-founded C2N in 2007. C2N currently employs over 120 people and is expanding its headquarters to the Cortex Innovation District in St. Louis.
"This test accurately and reliably detects brain amyloid plaques associated with Alzheimer's pathology with a single blood draw. FDA clearance will allow us to reach more patients, enabling earlier diagnosis and treatment initiation at the most effective time." — Randall Bateman
"FDA clearance marks a pivotal milestone in transforming Alzheimer's diagnosis and management and paves the way for effective therapies." — David Holtzman
Source: WashU Medicine News, "FDA clears blood test to aid evaluation for Alzheimer's disease" (August 21, 2026, Shawn Ballard)
▶ Original source: https://medicine.washu.edu/news/fda-clears-blood-test-to-aid-evaluation-for-alzheimers-disease/
