The latest Alzheimer’s blood test is the most promising yet, as it appears to accurately predict the disease 10 years before a clinical diagnosis could be made, researchers announced Sunday.

The test hinges on a brain protein called IRS-1, which is involved in insulin signaling. Based on people’s proportions of active and inactive forms of the protein, the investigators were able to say with 100% accuracy whether the sample came from a health older person, someone with diabetes or someone with Alzheimer’s. This held true even for samples taken from participants 10 years before they were diagnosed with Alzheimer’s, the team announced at the Society for Neuroscience conference in Washington, D.C.

Their findings appeared in the online version of The FASEB Journal, The Journal of the Federation of American Societies for Experimental Biology, in late October.

Other potential Alzheimer’s blood tests predict the disease within one to three years.

So far, only 174 individuals have participated in a trial of the IRS-1 blood test, so more expansive studies are needed before it is widely available, the investigators explained in a press release. The company behind the test, California-based NanoSomiX, plans to produce a commercial version.

While testing for Alzheimer’s and other dementias is controversial due to the lack of a cure, proponents argue that it opens the way for therapies that could weaken or even eradicate the disease in its early stages.