A blood marker can predict the progression of Alzheimer's disease.

A team of researchers from the Sant Pau Research Institute (IR Sant Pau) has demonstrated that the plasma biomarker p-tau217, obtained through blood tests, can predict the clinical progression of Alzheimer's disease even in the earliest stages, when symptoms are not yet evident.

The work, published in the journal Neurology , reinforces the role of blood tests in the future of dementia diagnosis and monitoring, reported Sant Pau Hospital in Barcelona on Monday.

The research, conducted within the Sant Pau Initiative on Neurodegeneration (Spin) cohort, included 731 people with and without cognitive impairment, with an average follow-up of up to 10 years.

The p-tau217 marker allows us to anticipate the rate of cognitive decline

Researchers analyzed levels of p-tau217—a specific form of the tau protein associated with neurodegeneration—and observed that this marker not only correlates with the presence of Alzheimer's, but also allows them to predict the rate of cognitive decline and the progression to more advanced stages of the disease, including dementia.

Ignacio Illán, a researcher at the Hospital de Sant Pau and director of the study, stated that this marker has "enormous potential" as a clinical tool, as it accurately identifies Alzheimer's disease and allows for estimating its rate of progression.

First author and neuropsychologist researcher Judit Selma-González noted that this biomarker can identify people who "do not yet have cognitive symptoms, but are at greater risk of developing them in the short or medium term."

Less invasive

Until now, the most reliable biomarkers for detecting and monitoring Alzheimer's required invasive techniques such as lumbar puncture or positron emission tomography, but this biomarker offers a noninvasive, more accessible, and more affordable alternative.

The study found that p-tau217 levels progressively increased from preclinical to advanced stages of dementia and were independently associated with a higher risk of cognitive decline. The marker also showed better prognostic capacity than its currently widely used cerebrospinal fluid equivalent, p-tau181.

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Researchers believe that the ability to use a blood test to determine this clinical status and monitor progression represents an important step toward more personalized and precise medicine.