(CNN) -- A simple blood test could let you know whether you will develop Alzheimer's disease.
According to a new study published in the journal Nature Medicine, doctors may be able to make predictions 16 years before symptoms begin.
One of the many changes in the brain that occur is the accumulation of a protein in the blood called neurofilament light chain, or NFL.
Researchers are testing for the changes in this protein, to measure nerve cell loss in the brain. They say the more "Nfl" in the blood, the more brain damage you have.
405 people across the world were part of the "Dominantly Inherited Alzheimer's Network."
Their NFL protein levels were measured through blood tests, brain images, and cognitive tests every 2.5 years, over the last seven. The study is still ongoing, but 243 were already found to have increasing levels of the protein. So far, 13 participants have developed the disease.
If this clinical trial proves successful, doctors are hopeful it will allow them to start treating patients early.