“This blood test clearly identifies Alzheimer’s tau tangles, which is our best biomarker measure of Alzheimer’s symptoms and dementia,” co-senior author Dr. Randall Bateman, a professor of neurology at the Washington University School of Medicine in St. Louis, said in a news release.

Researchers have developed a blood test based on a protein biomarker for tau tangles that can help diagnose Alzheimer’s disease and also provide insight on how far the disease has progressed.

A new blood test test could determine how far Alzheimer's has progressed and could also help confirm whether another condition is causing a person’s cognitive symptoms.