A new blood test tracks brain injury after stroke and predicts outcomes months to years later, researchers have said.
The biomarker, brain-derived tau (BD-tau), could let clinicians monitor how damage evolves in the hours and days after stroke, which scans alone cannot show.
In ischaemic stroke, part of the brain loses its blood supply. Decisions rely on CT or MRI images, but in the acute phase these give only snapshots in time.
Dr Steffen Tiedt is scientist at the Institute for Stroke and Dementia Research and attending physician in the Stroke Unit at LMU University Hospital’s Department of Neurology.
He said: “In stroke care, we currently face the problem that we cannot continuously track how brain injury evolves over time, and this limits our treatment decisions.”
The research, led by LMU University Hospital with international partners, analysed data from more than 1,200 stroke patients.
BD-tau was measured repeatedly from admission through day seven.
Early BD-tau levels, taken within hours of symptom onset, reflected initial injury and predicted final infarct size (the area of dead tissue).
Rises over the first 24 to 48 hours tracked infarct growth.
BD-tau also predicted recovery, forecasting functional outcome at 90 days and beyond at least as well as, or better than, other blood biomarkers and even imaging-based infarct volumes.
Treatment effects were visible too: after thrombectomy (a procedure to remove a clot), BD-tau rose less when the blocked vessel was fully reopened.
In a randomised trial, BD-tau rises were also smaller with the neuroprotectant nerinetide than with placebo.
Tiedt said: “We don’t just need a picture from the beginning of a stroke, we need a way to follow the course of brain injury over time.
“BD-tau could become a kind of ‘troponin for the brain’, an objective blood marker that makes progression and treatment effects measurable.”
The team said further studies are needed to define reference ranges and thresholds, and to speed up BD-tau testing.
In time, such a test could help clinicians track disease course more closely, spot complications earlier, and assess new therapies more efficiently in trials.
