Clinical utility of measuring circulating glial fibrillary acidic protein in severe stroke

Stroke is a global health concern, requiring early and accurate diagnosis for effective treatment. Differentiating between ischaemic stroke and haemorrhagic stroke is critical, as treatment strategies differ significantly. While neuroimaging is the gold standard for differential diagnosis of stroke code patients, blood biomarkers could be a promising and cost-effective diagnostic method for earlier diagnosis in the prehospital setting, where neuroimaging is unavailable. Studies demonstrate that the biomarker glial fibrillary acidic protein (GFAP) can distinguish ischaemic and haemorrhagic stroke with high specificity, though sensitivity varies based on sampling timing and assay methodology. This narrative review explores the potential of GFAP as a diagnostic biomarker in severe strokes and in identifying large vessel occlusions (LVOs). While studies suggest a correlation between higher GFAP levels and stroke severity in haemorrhagic stroke, evidence for this in ischaemic stroke is inconclusive. Combining GFAP with clinical stroke scales and additional biomarkers has shown promise in identifying LVO. Future research should focus on refining the diagnostic role of GFAP in severe strokes, optimising sample timing and including large cohorts representing the full spectrum of stroke severities.