New Blood Test Could Predict When Alzheimer’s Symptoms Will Present

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AIzheimer’s disease is a difficult disease to diagnose. Clinical markers (amyloid plaques and tangles of filamentous tau proteins that accumulate in the brain) are best measured by PET, which is expensive and not widely available.

The search for simpler, more reliable ways to detect the disease has been going on for years, and the FDA recently approved a blood test for people over 55. Today, new research published in Natural medicine shows promise not only in detecting Alzheimer’s disease, but also in predicting when symptoms will appear.

Neuroscientists at the University of Washington took blood samples from 600 people aged 62 to 78 who did not suffer from cognitive impairment. By measuring levels of a phosphorylated version of tau, p-tau217, they were able to create a model that could estimate the onset of Alzheimer’s symptoms with a margin of error of three to four years.

“Amyloid and tau levels are similar to tree rings: If we know the number of rings a tree has, we know how many years old it is,” study author Kellen K. Petersen said in a statement. “It turns out that amyloid and tau also accumulate in a consistent pattern and that the age at which they become positive strongly predicts when a person will develop Alzheimer’s disease symptoms. We found that this is also true for plasma p-tau217, which reflects both amyloid and tau levels.”

Read more: “What Alzheimer’s looks like from the inside out”

This is encouraging news for the millions of Americans who are at risk of developing Alzheimer’s disease, but it comes with some important caveats. Concerned about false positives, many experts are sounding the alarm about the generalization of blood tests in people who have not shown any symptoms of the disease. Blood tests, they say, should be just one part of a more comprehensive diagnostic protocol.

Although this latest test will need some fine-tuning before it’s ready for prime time, it can still be used in clinical trials.

“In the short term, these models will accelerate our research and clinical trials,” said study author Suzanne E. Schindler. “Ultimately, the goal is to be able to tell each patient when they are likely to develop symptoms, which will help them and their doctors develop a plan to prevent or slow symptoms.” »

A number of factors have been linked to delayed disease progression, such as a healthy diet, active lifestyle and social engagement, but there are only two recently approved treatments to delay Alzheimer’s disease when it is detected early.

It’s a big step in the right direction, but it’s not exactly a miraculous breakthrough.

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Main image: GerryShaw / Wikimedia Commons

• Jake Currie

  Published on February 24, 2026

  Jake Currie is a writer based in Brooklyn, New York.