On May 15, 2025, the FDA (Food and Drug Administration) gave the green light to the very first blood test to help diagnose Alzheimer’s disease. Called PRECIVITYAD2 and developed by the American company C2N Diagnostics, this test marks a major advance: it can be used in addition to existing methods, to guide the diagnosis faster, as soon as cognitive disorders appear.
How does this new blood test against Alzheimer work work?
In fact, Alzheimer’s disease manifests itself by a progressive accumulation of amyloid protein in the brain, forming plates, followed several years later by the appearance of tau protein tangles. Cognitive disorders generally occur when these tangles become detectable, either when the disease is well advanced.
So far, the diagnosis of Alzheimer’s diagnosis was essentially based on heavy and often late exams: brain MRI, pushed neuropsychological evaluation, even sometimes lumbar puncture to analyze cerebrospinal fluid. The PRECIVITYAD2 test offers a less restrictive alternative, by measuring the presence of a key biomarker of the disease directly in the blood: the ratio between beta-amyloid proteins 42 and 40. 499 plasma samples taken from adults with cognitive disordersit obtained 91.7 % success.
A tool reserved for over 55s that have signs
The FDA affirms this, this test “has demonstrated satisfactory clinical performance in the evaluation of patients with signs of cognitive disorders”. On the other hand, it will not be presented as a free access test for general public, but a tool for health professionals who wish to refine a clinical suspicion. Therefore, it will only be for people aged 55 and over, in a framed medical framework.
A doctor may thus, in the event of early symptoms, prescribe this blood analysis in order to guide the decision to use – or not – to further examinations. In itself, the test is not designed to replace traditional diagnostic methods, but to serve as a filter or prior indicator. And accelerate things.
A medical advance that could change the situation
For the medical community, this authorization opens a promising path. As the FDA press release pointed out, this type of test “represents significant progress towards less invasive assessments“For neurodegenerative pathologies still too little detected in time.
According to experts, the simplification of the screening route could promote earlier management of the disease, provided you are well supervised. This test does not predict the future development of the disease, nor constitutes formal proof. But it could accelerate access to treatment or follow -up, in an often clogged health system.
Asked a few months ago about the advances of these tests, Dr. Christophe de Jaeger, a geriatrician and researcher also shared his enthusiasm: “This test will really advance things routine, because it is easy to prescribe a blood test. This will allow many patients to be more quickly diagnosed and therefore more quickly taken care of, according to their clinical health and disorders “ he details. For him, “The role of the doctor will be to determine the relevance of the results and to see whether or not an Alzheimer’s disease can be suspected, because the diagnosis of Alzheimer’s is complex and you have to know how to question it “.
Pending a possible marketing in Europe, professionals welcome a decision which, failing to revolutionize the diagnosis, will simplify a key step.