Scientists have developed a promising new way to estimate when a person might start showing symptoms of Alzheimer’s disease — using just a blood test.
Researchers at Washington University School of Medicine in St. Louis report that their method can predict the likely timing of symptoms within about three to four years, a breakthrough that could transform both research and future patient care.
Alzheimer’s disease affects more than seven million Americans, and the cost of care for Alzheimer’s and other dementias is expected to approach $400 billion in 2025.
Because there is still no cure, experts say early prediction could be key to developing treatments that prevent or delay the disease.
The new approach relies on measuring a protein in the blood called p-tau217.
This protein is linked to the buildup of amyloid and tau — abnormal proteins that accumulate in the brain many years before memory loss and other symptoms appear.
Scientists have known that these brain changes begin long before diagnosis, but until now it has been difficult to estimate exactly when symptoms would start.
In the study, published in Nature Medicine, researchers analyzed data from more than 600 older adults who were living independently and participating in long-term Alzheimer’s research projects.
By tracking p-tau217 levels in their blood and comparing them with when symptoms eventually appeared, the team created models that function like biological “clocks.”
These clocks estimate how long it may take for symptoms to develop once p-tau217 levels become elevated.
For example, people whose levels rose around age 60 tended to develop symptoms about 20 years later, while those whose levels increased at age 80 often developed symptoms within about 11 years.
The findings suggest that younger brains may be more resilient, allowing more time before symptoms appear.
Researchers say this blood test approach has several advantages.
It is much cheaper, easier, and less invasive than brain scans or spinal fluid tests currently used in research settings. In the near future, it could help scientists design faster and more efficient clinical trials for drugs aimed at preventing Alzheimer’s.
Instead of waiting many years to see who develops symptoms, trials could focus on people most likely to experience changes within a shorter timeframe.
Eventually, doctors may be able to use such tests to help patients plan for the future. Knowing when symptoms are likely to begin could guide decisions about lifestyle changes, medical treatments, and long-term care. However, experts caution that the test is not yet ready for routine use in healthy individuals and more research is needed before it becomes part of standard medical care.
The team also found that their prediction models worked across different versions of p-tau217 blood tests, suggesting the method is reliable and could be widely applied. Future studies may combine this marker with other blood biomarkers to improve accuracy even further.
While there is still much work ahead, the discovery offers hope that a simple blood test could one day provide an early warning for Alzheimer’s. Such a tool could give patients and families precious time to prepare and, as new treatments emerge, possibly delay the disease before it disrupts memory and daily life.
Source: KSR.
