Abstract 57: Rapid Prehospital Diagnosis of Intracerebral Hemorrhage by Measuring GFAP on a Point-of-Care Platform

Background: The rapid differentiation between intracerebral hemorrhage (ICH) and ischemic stroke (IS) in patients with symptoms of acute stroke is decisive for triage and initiation of targeted therapies. Glial fibrillary acidic protein (GFAP) is a highly promising blood biomarker indicating acute ICH. In this study we investigated the potential of a new GFAP plasma test on a point-of-care (POC) platform for rapidly distinguishing ICH from IS in the prehospital phase. Methods: Patients with symptoms of acute stroke admitted within 6 hours of symptom onset were enrolled. Blood samples were collected already in the prehospital phase in most patients. Plasma GFAP measurements were performed on the i-STAT Alinity® (Abbott) device (duration of analysis 15 min). The primary endpoint was the final diagnosis at hospital discharge categorized as ICH, IS or stroke mimics. Results: 155 patients were enrolled (mean age 75±13, 49% females; final diagnosis 33 ICH, 115 IS, 7 stroke mimics). Prehospital GFAP serum concentrations were strongly elevated in ICH patients compared to IS patients (mean 2283±3821 pg/mL, median 144 [IQR 52.5-2562] vs. mean 45±25 pg/mL, median 29 [IQR 29-53]; p<0.001). In patients with a moderate to severe neurological deficit (NIHSS > 7), GFAP values below 30 pg/mL were associated with a negative predictive value of 100% (i.e. ruling out ICH). The probability of ICH increased in parallel with higher GFAP levels. GFAP concentrations above 120 pg/mL indicated ICH with a positive predictive value of 94%. Conclusion: Rapid prehospital GFAP measurements on a point-of-care platform allow a reliable differentiation between patients with IS and ICH. This opens the potential for optimized triage and for the administration of antidots in severely affected patients with suspected anticoagulation-associated ICH.