Blood Test Predicts Age When Alzheimer’s Symptoms Start

A new study showed that a blood test can estimate when someone will begin to show Alzheimer’s symptoms. This could help researchers better design approaches to prevent or treat symptoms.

Alzheimer’s disease is a brain disorder that slowly destroys memory and thinking skills. It’s the most common form of dementia. There is no cure, but there are treatments.

People with Alzheimer’s disease have high levels of a protein called p-tau217 in their blood. Researchers studied data from 603 people who had multiple p-tau217 blood tests over time. They used this data to create a “clock” model.

The model could identify individuals likely to develop Alzheimer’s symptoms. For those who developed symptoms, it could estimate the age of symptom onset. The time between the first high test result and the first symptoms shrank with age. A person with high p-tau217 levels at age 60 would have symptoms about 20 years later. However, a person with high p-tau217 at age 80 would develop symptoms after about 11 years.

The findings suggest a single blood test might be used to estimate how long it will take for someone to show Alzheimer’s symptoms. But more research is needed before the test could be used in the clinic. Researchers are still working to improve the model’s predictions.

“Eventually, the goal is to estimate when individuals are likely to develop symptoms, which would help them and their doctors to create a plan to prevent or slow symptoms,” says Dr. Suzanne Schindler at Washington University in St. Louis.