Strokes are serious medical emergencies that can cause lasting damage to the brain. Until now, doctors have mostly relied on brain scans like CT or MRI to understand what’s happening inside the brain after a stroke.
But these scans only give a quick snapshot, and they’re not always easy to repeat often. That’s a big problem when trying to track how brain damage develops over hours or days after a stroke.
Unlike injuries to other organs—like the heart or kidneys—where blood tests can show the level of damage, the brain has not had a similar blood marker. But that may be about to change.
Researchers at LMU University Hospital in Germany, along with international partners, have found that a new blood marker, called brain-derived tau (BD-tau), can help track brain damage over time in patients who’ve had an ischemic stroke.
This discovery, published in the journal Science Translational Medicine, could help doctors make better decisions during treatment and recovery.
An ischemic stroke happens when blood flow to part of the brain is blocked. This can lead to symptoms like trouble speaking, weakness, or paralysis. Right now, doctors decide on treatments based mainly on brain scans, but those don’t show how damage is changing hour by hour or day by day. Repeated scans are hard to do and may not give the full picture.
Dr. Steffen Tiedt, a stroke expert and neurologist at LMU, started this research in 2013. He and his team wanted to find a simple blood test that could show how much damage the brain had suffered and whether treatments were working.
That’s how they found BD-tau, a type of tau protein that comes only from the brain. Measuring this protein in the blood gives doctors a clearer view of what’s going on inside the brain after a stroke.
In their study, the team looked at blood samples from more than 1,200 stroke patients. They tested BD-tau levels from the time patients arrived at the hospital until seven days later. They also confirmed their findings using two more groups of patients, including those from a clinical drug trial.
They discovered that high levels of BD-tau in the blood shortly after a stroke were linked to larger areas of brain damage. BD-tau levels that kept rising in the first 24 to 48 hours often meant the damage was getting worse. The researchers also found that patients with lower levels of BD-tau tended to recover better in the months that followed.
The test was also helpful in showing whether treatments were working. For example, patients who had a successful thrombectomy—a procedure to reopen a blocked blood vessel—had smaller increases in BD-tau. In another study, patients who received a special drug called nerinetide had much lower rises in BD-tau compared to those who got a placebo.
Dr. Tiedt says BD-tau could become like troponin, a blood marker used to measure heart attacks—but for the brain. It could give doctors a simple, repeatable way to track brain injury and see if treatments are working.
The test isn’t ready for everyday use yet. Researchers still need to figure out what BD-tau levels are normal or dangerous, and they hope to develop faster versions of the test that can be used at the bedside. But the potential is big. A blood test like this could help doctors catch problems earlier, follow recovery more closely, and improve care for stroke patients.
It could also help researchers study new drugs and therapies more efficiently, and it may even be useful in other brain conditions, like head injuries or Alzheimer’s disease.
If you care about stroke, please read studies that diets high in flavonoids could help reduce stroke risk, and MIND diet could slow down cognitive decline after stroke.
For more health information, please see recent studies about antioxidants that could help reduce the risk of dementia, and tea and coffee may help lower your risk of stroke, dementia.
Copyright © 2025 Knowridge Science Report. All rights reserved.
