A new blood test may be 90% accurate at predicting whether someone will develop Alzheimer’s disease within the next three years.

Researchers at Georgetown University tested the blood of 525 people over the age of 70 over a period of five years. They then compared the results of 53 people who developed Alzheimer’s or cognitive impairment with 53 people who did not experience cognitive decline. They found different levels of 10 blood lipids, or fats, in each group. Tracking these 10 markers was predictive of who would develop cognitive decline, with 90% accuracy.

So far, the test appears to work to predict cognitive decline three years before symptoms appear, but the researchers are looking to see whether it may work even earlier. They also plan to repeat the experiment with a larger group of people, which will be necessary before a standardized blood test could be implemented in physician’s offices.

If further studies confirm the results, the blood test would provide a much better tool for diagnosing the devastating disease, which can currently only be detected with expensive and often unreliable brain scans and lumbar punctures.