The main promise of a blood marker for CTE is not certainty, but earlier direction. At present, the condition is still defined by what is seen after death, so any living-world test has to be judged against a difficult standard. That means a useful biomarker would likely be one piece of evidence in a broader clinical picture, not a standalone answer. For readers, the important question is less โcan blood prove CTE?โ and more โhow well can it separate likely cases from other causes of symptoms that can look similar?โ
This distinction matters because head injury history, mood changes, memory problems and impulse issues are not specific to CTE. Depression, sleep disruption, substance use, medication effects and other neurological conditions can overlap with the same complaints. A blood test that tracks tau-related signals may improve confidence, but it could still reflect brain injury more generally rather than one single disease process. In other words, a marker can be clinically helpful even if it is not perfectly disease-defining.
The new research angle is also about timing. If blood markers can be linked to later brain findings, they may eventually help identify who needs closer follow-up, more careful symptom monitoring or enrollment in studies of possible treatments. That is especially relevant because CTE has no proven disease-modifying therapy yet. For now, the value of earlier identification may lie in planning, support and reducing further exposure to head impacts, rather than in confirming a treatment path.
There is also an evidence lesson here for families and sports communities. A biomarker is only as strong as the studies validating it across different people, ages and exposure histories. Until then, the most responsible interpretation is cautious optimism: promising science, but not a finished clinical tool.
Early diagnosis
Chris Nowinski used to be a college football player and a WWE wrestler. Now heโs a scientist and patient advocate studying one of the biggest problems he and his friends have faced: concussion damage.
Nowinski says he felt pressure to play football โbecause I was tall and strong in high school โ and I did not have any idea of what I was getting into.โ
After retiring from wrestling due to concussion symptoms in 2003, Nowinski began researching head trauma in sports. Heโs had two former teammates die with chronic traumatic encephalopathy (CTE), a serious condition where repeated blows to the head can cause brain damage, leading to symptoms like memory loss, mood swings and trouble moving.
In 2007, Nowinski started the Concussion Legacy Foundation, which supports veterans and athletes by promoting CTE scientific research and advocating for policy changes to prevent it. To study the condition, Nowinski and his foundation partnered with scientists at Boston Universityโs CTE Center led by Michael Alosco and Thor Stein to recruit people with suspected CTE to give blood and agree to donate their brains for research after they die.
Normally, CTE is only diagnosed after death. Itโs common in American football players, who suffer repeated blows to the head from tackles and hard landings on the field, but can also be found in people who played a wide range of amateur sports as kids. CTE made headlines in July when Shane Tamura, who believed he had the condition, went to the NFLโs office building in Manhattan and shot four people before killing himself. After an autopsy, the New York City Medical Examinerโs office later confirmed that Tamura did have early stage CTE.
Diagnosing CTE in living people will be immensely important for patients and families, Nowinski says. โThis is a much larger disease than anybody realizes, and once we can prove that, hopefully that will generate more interest in developing disease-modifying treatments.โ
CTE, like Alzheimerโs disease, is associated with a buildup of tau protein in the brain. A blood test measuring the ratios of certain tau proteins can help diagnose Alzheimerโs disease. Nowinski and CLF are partnering with Boston University researchers Alosco and Stein to create a similar blood test for CTE.
Last year, the first patient in their study passed away. The man, Chip Collins, played tackle football for eight years and had an advanced form of CTE. Alosco, Stein and their colleagues will now be able to compare the damage in Collinsโ brain to proteins they found in blood he donated during his life to begin validating the studyโs diagnostic approach.
Meanwhile, a Original PostHBiOCkCICnYCTnEciTh0mKqt50WSW0g/15" target="_blank" rel="noopener noreferrer" shape="rect">paper published in Science last month suggested that CTE is not just caused by repeated blows to the head, but also DNA damage and immune system responses similar to that of patients with Alzheimerโs disease. If confirmed, this could lead to new research for better therapies.
Though there are currently no treatments for CTE, just having a diagnosis could change how patients and loved ones deal with some of the more negative symptoms, like aggression and addiction, Nowinski says.
But his ultimate goal is to prevent the condition from happening at all. Kids and parents need to understand whatโs at stake when they sign up for a youth team, he says. โThis is the only major brain disease that is entirely optional.โ โย Annika Inampudi