Alzheimer’s Blood Test Breakthrough May Replace Costly Brain Scans

This affordable test detects Alzheimer’s with over 90% accuracy—years before symptoms appear—and could democratize early diagnosis worldwide.

Scientists at Washington University School of Medicine have developed a low-cost blood test that detects Alzheimer’s with over 90% accuracy. Unlike PET scans, which can cost thousands of dollars, or spinal taps, which are invasive and time-consuming, this test requires only a standard blood draw and could be offered in regular doctor’s visits. Even more impressive: it can identify Alzheimer’s years before symptoms arise, giving patients and families precious time to prepare, intervene, and seek support.

Alzheimer’s affects more than 6 million Americans and nearly 55 million people worldwide. By the time symptoms appear, significant brain damage has often already occurred. That’s why early detection is critical—not only for managing care, but also for enrolling patients in clinical trials and accelerating the development of effective treatments.

The blood test works by measuring levels of amyloid beta and tau proteins—key biomarkers associated with Alzheimer’s—in combination with other clinical factors. In trials, it has shown a remarkable ability to predict which patients will go on to develop memory loss and cognitive decline. The test is currently undergoing large-scale validation in diverse populations and may receive regulatory approval within the next year or two.

Beyond the science, the implications for equity are profound. High-quality brain imaging is expensive and often unavailable in lower-income communities, both in the U.S. and globally. A simple, affordable test that can be administered in any clinic has the potential to democratize access to early diagnosis and improve outcomes across the board.

While there’s still no cure for Alzheimer’s, this breakthrough represents a major step forward in the fight against the disease. And it’s a reminder that sometimes, the most powerful innovations don’t cure the illness—they change the timeline.