Just because someone has amyloid plaques in their brain doesn’t necessarily mean they have Alzheimer’s disease right now. Research shows that these plaques can build up years—even decades—before cognitive symptoms ever appear.That’s why this new blood test isn’t meant to be used on its own. It’s not a one-and-done diagnosis tool. But it’s a powerful addition to the diagnostic process—less invasive than a spinal tap, more accessible than a PET scan, and a big step forward in catching Alzheimer’s