That information could be reassuring or terrifying, but for now it’s a potential tool to speed drug development by helping to identify and enroll high-risk people into studies of possible Alzheimer’s treatments or preventive strategies.

Already large clinical trials are testing if certain drugs could prevent or at least delay the disease—and if any of those pan out, doctors will need an easy way to tell who should try them.

The scientists behind the new study stress that it’s too soon for healthy people to seek out the so-called p-tau217 test, which is currently used to help diagnose whether people experiencing cognitive problems have Alzheimer’s or another disorder.