...
By Lydia Patrick
Life & Trends Reporter
0
Share
Newsweek is a Trust Project member
See more of our trusted coverage when you search.Prefer Newsweek on Googleto see more of our trusted coverage when you search.
A single blood test may be able to predict when a person will develop Alzheimer’s symptoms—years before memory loss begins—according to new research from the Washington University School of Medicine in St Louis.
According to the researchers, their concept could estimate the age of onset of Alzheimer’s symptoms to within three to four years—an ability that could transform both clinical trials and, eventually, how doctors identify people most likely to benefit from preventive treatments.
“Our work shows the feasibility of using blood tests, which are substantially cheaper and more accessible than brain imaging scans or spinal fluid tests, for predicting the onset of Alzheimer’s symptoms,” said senior author Suzanne E. Schindler, MD, PhD, an associate professor of neurology at WashU Medicine. “In the near term, these models will accelerate our research and clinical trials.”
Read More on Health
“Eventually, the goal is to be able to tell individual patients when they are likely to develop symptoms, which will help them and their doctors to develop a plan to prevent or slow symptoms,” she added.
More than 7 million Americans currently live with Alzheimer’s disease, and the Alzheimer’s Association projects that the national cost of care will reach nearly $400 billion in 2025.
While there is still no cure, scientists hope that predicting who is at highest risk—and when symptoms are likely to begin—could help guide early interventions.
...
How The Test Works
The model is powered by a blood marker called p‑tau217, a protein linked to the buildups of amyloid and tau in the brain—the two defining features of Alzheimer’s disease. These proteins begin accumulating many years before memory problems emerge.
To build the prediction model, Schindler and colelagues analyzed data from 603 older adults who were part of two major Alzheimer’s research efforts: the WashU Knight Alzheimer Disease Research Center and the nationwide Alzheimer’s Disease Neuroimaging Initiative (ADNI).
Participants lived independently at the time they entered the studies. Their blood samples were tested using PrecivityAD2—an Alzheimer’s diagnostic test from the St. Louis-based company C2N Diagnostics—as well as several other p‑tau217 blood tests, including one cleared by the U.S. Food and Drug Administration.
Paper author and neurologist Kellen Petersen said that amyloid and tau levels in the brain act almost like a biological timeline.
“‘Amyloid and tau levels are similar to tree rings—if we know how many rings a tree has, we know how many years old it is,’” he explained.
“‘It turns out that amyloid and tau also accumulate in a consistent pattern and the age they become positive strongly predicts when someone is going to develop Alzheimer’s symptoms.
"We found this is also true of plasma p‑tau217, which reflects both amyloid and tau levels.’”
Younger Brains May Withstand Damage Longer
The study found notable age differences in how long people stay symptom‑free after p‑tau217 levels rise.
- Someone whose p‑tau217 levels were elevated at age 60 typically developed symptoms 20 years later.
- Someone whose levels did not rise until age 80 developed symptoms within 11 years.
Researchers say this suggests younger brains may be more resilient to early Alzheimer’s changes, while older adults may show symptoms sooner even with lower levels of disease markers.
Useful Across Different Tests
The model performed well regardless of which company’s p‑tau217 blood test was used—something the researchers say demonstrates its strength and reliability.
To promote transparency, the team also released all of its model‑development code, and Petersen created a web‑based tool for scientists to explore how the “clock” works.
“These clock models could make clinical trials more efficient by identifying individuals who are likely to develop symptoms within a certain period of time,” Petersen said.
“With further refinement, these methodologies have the potential to predict symptom onset accurately enough that we could use it in individual clinical care.”
Do you have a tip on a health story that Newsweek should be covering? Do you have a question about Alzheimer's disease? Let us know via health@newsweek.com.
Reference
Petersen, K. K., Milà-Alomà, M., Li, Y., Du, L., Xiong, C., Tosun, D., Saef, B., Saad, Z. S., Du-Cuny, L., Coomaraswamy, J., Mordashova, Y., Rubel, C. E., Meyers, E. A., Shaw, L. M., Dage, J. L., Ashton, N. J., Zetterberg, H., Ferber, K., Triana-Baltzer, G., … Schindler, S. E. (2026). Predicting onset of symptomatic Alzheimerʼs disease with plasma p-tau217 clocks. Nature Medicine. https://doi.org/10.1038/s41591-026-04206-y
View 0 Comments
Submit Correction
View Editorial & AI Guidelines