FDA clears PrecivityAD2, an Alzheimer's blood test

Getting checked for Alzheimer's used to mean a brain scan or a spinal tap. Now it can start with a simple blood draw. The FDA cleared C2N Diagnostics' PrecivityAD2 test on Aug. 20. It's now available for adults as young as 40 who show early signs of cognitive decline. The test detects Alzheimer's-linked amyloid plaque biomarkers with more than 90% accuracy. It's the first such test cleared for patients this young.

Earlier blood tests like this one were only cleared for older adults. Alzheimer's has mostly been treated as a disease of aging. Expanding to age 40 reflects something doctors have known for a while. Early-onset cases exist. Catching biomarkers sooner means starting treatment sooner, when it may do more good. The test isn't a diagnosis on its own. Doctors still combine it with a full clinical evaluation before telling a patient anything definitive.

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How many people will actually get tested now that a blood draw can replace a brain scan? Cost and insurance coverage will decide that as much as the science does. A test this much easier to administer only matters if doctors, and insurers, actually put it to use.