Headlines this week say scientists have found a blood test that “opens the door” to diagnosing CTE in living people. The study behind them is real, published in one of medicine’s leading journals, and worth paying attention to. But it is an early step, not a test anyone can get. Here’s our plain-English take on what it is and what it isn’t.
What the study found
Researchers at Washington University School of Medicine in St. Louis measured a fragment of the tau protein, called eMTBR-tau243, in blood. Tau is the protein that builds up in the brain in CTE. In 11 people whose CTE was confirmed after death, levels were higher than in healthy people and rose as the disease got worse. The study was published in JAMA on November 13, 2026. (WashU Medicine)
What it doesn’t show yet
- It missed early CTE. The marker did not reliably detect early-stage CTE, the stage where a diagnosis would help most.
- It can’t tell CTE from Alzheimer’s. Alzheimer’s disease raises the same marker even more, and the two often occur together, especially in older adults.
- The study was very small. Only 11 people with CTE were tested. The researchers themselves say much larger studies are needed and that this marker would not be used on its own.
- Independent experts are cautious. A neuropathologist who was not involved told the Associated Press the finding is very preliminary. (AP)
- Note the financial ties. Several of the authors have financial ties to the company that licensed the technology. That’s common in medical research, but readers should know it.
What it means for you
Today, CTE can still be confirmed only by examining the brain after death. No blood test or scan can diagnose it in a living person yet. If you or someone you love has symptoms such as memory problems, mood changes or depression, please see a doctor: many of these symptoms have other causes that can be treated.
This is a promising direction, and it joins several other efforts to diagnose CTE during life. We’ll keep following it and report back when larger studies are published. See our Research page for the wider picture.
Research news is not medical advice; talk with a doctor about your own situation. If you or someone you know is struggling, call or text 988 (Suicide & Crisis Lifeline, U.S.).
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