The U.S. Food and Drug Administration has cleared PrecivityAD2, a blood test that helps identify whether a patient has amyloid plaques in the brain, one of the defining features of Alzheimer's disease. The underlying technology was invented at Washington University School of Medicine in St. Louis, and the test itself was developed and validated by C2N Diagnostics, a startup spun out of the university.
What sets this test apart from some other FDA-cleared blood tests for Alzheimer's biomarkers is the measurement method. Rather than relying on immunoassays, PrecivityAD2 uses high-resolution mass spectrometry to produce quantitative readings of the biomarkers it targets. For patients, the practical difference is the route to an answer: blood-based testing is less invasive than a spinal tap to collect cerebrospinal fluid, which has long been one of the standard ways to confirm amyloid pathology.
The timing matters because the first drugs shown to slow the progression of Alzheimer's have only recently reached patients, and those treatments work better the earlier they are started. A simpler way to check for amyloid could shorten the gap between a patient's first worrying symptoms and a clear picture of what is driving them. Additional candidate drugs remain in development.
A blood result is not a diagnosis on its own. The test is cleared as an aid for certain patients, and its results are meant to be interpreted alongside a person's clinical history and other diagnostic information by the clinician managing their care.