Alzheimer’s disease, which progressively and irreversibly destroys memory and thinking skills in the brain, affects an estimated 5.1 million Americans. Since the first symptoms of Alzheimer’s usually appear after age 60, many affected individuals don’t even know they have the disease and therefore can’t work to prevent it.

But a new blood test may hold the key to early detection. According to research published in the published in the Journal of the Federation of American Societies for Experimental Biology (FASEB) and presented at a Washington, DC conference for the Society for Neuroscience, blood tests may be able to detect Alzheimer’s up to 10 years before symptoms appear.

Though the research is still in its early stages and the sample size is too small to apply to a commercial scale yet, the results so far are promising.

Essentially, the study’s authors discovered a way to measure the brain’s insulin resistance and discovered that the presence of insulin resistance indicated Alzheimer’s in 100% of cases studied.

Researchers compared blood from living Alzheimer’s patients to frozen blood taken from the same patients 1-10 years before they were diagnosed. By monitoring levels of an insulin receptor called IRS-1 in each patient’s blood, researchers were able to correctly identify which patients had Alzheimer’s, even in blood samples that were 10 years old.

That 10-year diagnostic window could be huge advantage for potential Alzheimer’s patients. Early diagnosis allows patients to partake in behavioral interventions and treatments that could slow or even stall the progression of the disease.

“Early detection is critically important in the treatment of this disease, it benefits both the patient and their families. It allows them time to plan and find community resources to help their family. People in early stages will be able to report symptoms and concerns and understand the early stages of their disease, this blood test could change the whole treatment protocol for the disease,” says Laurie Malone, Managing Partner and CEO of Golden Heart Senior Care.

At the conference, the study’s lead author, neuroscientist Dimitrios Kapogiannis told Bloomberg Businessweek that “We will need replication and validation, but I’m very optimistic this work will hold.”

The study’s senior author, Dr. Ed Goetzl, made a similar statement to Time, adding that they hoped to replicate their results on a larger sample and expand upon the findings. Goetzl hopes that understanding how insulin resistance affects Alzheimer’s will help pharmaceutical companies develop better drugs to treat the disease.