Study Shows Blood Test Can Predict Onset of Alzheimer’s Symptoms Years in Advance

North Bethesda, MD — February 19, 2026 — A new study developed and launched by the Foundation for the National Institutes of Health’s Biomarkers Consortium shows that a single blood test can assess not only a person’s risk of developing Alzheimer’s disease but also predict approximately when symptoms will start, with an average margin of error of about three to four years. 

The study was published today in Nature Medicine.

“With advances in Alzheimer’s blood-based diagnostics, like in this study, the field is moving closer to earlier diagnosis and more accessible, precise treatments for people living with the disease,” said Alessio Travaglia, PhD, director, Translational Science, Neuroscience and Rare Diseases, at the FNIH. “Advances in Alzheimer’s research are gaining remarkable momentum, built on decades of scientific progress and the growing role of biomarkers in accelerating the development of new therapies and diagnostics.”

Researchers in the study analyzed p-tau217, a protein linked to Alzheimer’s disease, in blood samples collected over a period of up to 10 years from more than 600 adults (ages 62-78 years) who were initially free of cognitive symptoms. The team then built statistical clock models that related blood p-tau217 changes over time to future symptom onset.

People with higher levels of plasma p-tau217 tended to develop Alzheimer’s symptoms sooner, and older individuals developed symptoms more quickly after reaching elevated levels of this protein. The model was able to estimate how many years away a person might be from developing memory and thinking problems related to Alzheimer’s, with an accuracy of within 3-4 years. This level of accuracy could prove especially helpful for clinical trials, helping researchers select participants most likely to develop symptoms within a trial’s timeframe—making studies more efficient and powerful.

The research team also developed a web-based application that allows scientists to visualize how levels of plasma p-tau217 change over time and how they relate to Alzheimer’s symptoms. The interactive tool helps researchers to explore complex relationships between plasma p-tau217, age, and symptoms.

“This study shows that it is possible to use blood tests to predict not only if individuals are likely to develop Alzheimer’s symptoms but also to estimate when the symptoms will begin,” said Suzanne Schindler, MD, PhD, the study’s senior author and an associate professor of neurology at Washington University School of Medicine in St. Louis. “We are working to make these models even more accurate.”

Both Alzheimer’s biomarker testing in people without cognitive symptoms and use of the web-based application should be limited to research settings, the study authors wrote.

The study builds on data and insights generated from previous and ongoing FNIH research partnerships committed to advancing understanding of Alzheimer’s and other neurodegenerative diseases. Beginning with the Alzheimer’s Disease Neuroimaging Initiative (ADNI) in 2004 and continuing through the Accelerating Medicines Partnerships^® and the Biomarkers Consortium, the FNIH has spearheaded numerous collaborative efforts focused on identifying and validating biomarkers for early detection and effective treatment of Alzheimer’s.

This study was supported by private-sector partners AbbVie Inc., the Alzheimer’s Association, The Alzheimer’s Drug Discovery Foundation’s Diagnostics Accelerator, Biogen, Johnson & Johnson, and Takeda.