Researchers have developed a blood test that can predict the likelihood that asymptomatic older adults will develop Alzheimer's symptoms within five to ten years. This test, known as p-tau217, provides a potential tool to accelerate the development of treatments.

The study revealed that those with high levels of p-tau217 have a 38% risk of cognitive decline in five years, increasing to 78% in ten years. The data come from an analysis of 2,684 older adults, published in JAMA and presented at the Alzheimer's Association International Conference in London, who were involved in long-term Alzheimer's research.

"We already have people coming in and saying, 'I want to do this blood test. I have a family history of Alzheimer's disease,'" said Jessica Langbaum of the Banner Alzheimer's Institute in Phoenix, something she strongly advises against, for now, reports the Associated Press (AP).

“These findings are pretty compelling,” Langbaum added, and a predictive blood test would be “really important,” but only if ongoing studies eventually find a drug that can help people before symptoms begin.

Considerations about the application of the test

The test measures a specific form of tau that is linked to the buildup of amyloid plaques in the brain. This blood biomarker makes it easier to identify people in early stages of the disease process.

Experts in the field have expressed the need for caution. Although the analysis may be promising, its use in healthy individuals must be approached with caution. It is recommended to wait until treatment options are available before undergoing testing.

Despite the positive results, only a portion of the participants were monitored for a full decade. This raises questions about the accuracy of long-term predictions. In addition, other risk factors could influence the results and complicate the diagnosis.

Open research on the p-tau217 assay has sparked interest, but the scientific community emphasizes that effective application will depend on the availability of treatments that intervene before the onset of symptoms. The discussion continues around prediction methods and their influence on clinical practice.

Following a predictive diagnosis, health systems and clinical guidelines are implementing structured pathways so that appropriate treatment is available in a timely manner.