
The American Heart Association said that a blood test may quickly differentiate brain bleeds from ischaemic (clot-caused) strokes, even before stroke patients reach the emergency room.
A preliminary study on this method will be presented at the American Stroke Association’s International Stroke Conference 2025.
Researchers investigated if blood levels of glial fibrillary acidic protein (GFAP) could help in quickly diagnosing different stroke types. GFAP is a protein, which is specific to the brain, and released into the bloodstream when brain cells are damaged.
The American Heart Association said that it is critical to differentiate between a haemorrhagic (bleeding) stroke and an ischemic stroke before starting treatment.
This distinction is typically done through imaging. However, delays in stabilising the patient, transporting them to the emergency room (ER), and performing a brain scan can lead to more brain cell damage.
The latest study included 353 participants who reached the emergency room within six hours of stroke symptom onset.
Blood samples were drawn before patients arrived at the emergency room at RKH Hospital in Ludwigsburg, Germany, and GFAP levels were tested using a portable blood analyser.
Brain imaging later confirmed 76 cases of intracerebral haemorrhage, 258 cases of clot-caused strokes, and 19 cases of conditions mimicking a stroke.
GFAP levels were then compared between these groups based on their diagnosis at hospital discharge.
Study lead author Love-Preet Kalra said: “It is crucial to differentiate these two types of stroke because they need opposite treatments.
“In ischemic stroke, you need to open the blocked blood vessel with clot-busting drugs or physically remove the clot.
“In contrast, in a bleeding stroke, you need to lower increased blood pressure and give medication to reverse the effects of certain blood-thinning drugs.”
In a 2024 parallel study, Kalra and colleagues found that GFAP levels could quickly identify patients with a bleeding stroke, even among those who were unresponsive.
The researchers tested whether GFAP levels could distinguish between haemorrhagic and ischemic strokes, as well as conditions that simulate a stroke.
The analysis found that GFAP levels were nearly seven times higher in patients with bleeding strokes than in those with clot-caused strokes. Additionally, GFAP levels were more than four times higher in patients with bleeding strokes than those with stroke mimics.
Additionally, GFAP levels predicted bleeding strokes with 90%-95% accuracy when age-based cut-off points were applied.
If larger studies confirm the results, Kalra said that early GFAP measurements could transform how individuals with stroke symptoms are treated.