Abstract Body: INTRODUCTION:
The rapid identification of acute intracerebral hemorrhage (ICH) in patients with symptoms of acute stroke is decisive for prehospital triage and initiation of targeted therapies. Glial fibrillary acidic protein (GFAP) is a highly promising blood biomarker indicating ICH. In this study we investigated the potential of a new GFAP point-of-care test for rapidly distinguishing ICH from ischemic stroke (IS) and stroke mimics in the
prehospital phase.

METHODS:
Acute stroke patients admitted within 6 hours of symptom onset were enrolled. Blood samples were collected in the prehospital phase. Plasma GFAP measurements were performed on the i-STAT Alinity® (Abbott) device (duration of analysis 15 min). The gold standard was the final diagnosis at hospital discharge categorized as ICH, IS or stroke mimics.

RESULTS:
353 patients were enrolled (mean age 74.6 ±13.4, years). GFAP concentrations were strongly elevated in ICH patients (n=76; median 208 pg/mL [IQR 60 – 5907]) compared to IS patients (n=258; median 30 pg/mL [IQR 29-51]) and stroke mimics (n=19; median 48 pg/mL [IQR 29-97]; p<0.001). Patients with anticoagulation-associated ICH had higher GFAP values compared to non-anticoagulated patients. Cut-off points were determined allowing diagnosis of ICH across distinct age groups with high positive predictive values (90.0 to 95.5%). Vice versa, in patients with a moderate to severe neurological deficit (NIHSS > 6), GFAP values below 30 pg/mL ruled out ICH with a negative predictive value of 100.0 %.

CONCLUSION:
Prehospital GFAP measurements on a point-of-care platform allow a reliable identification of patients with ICH. This opens the potential for optimized triage as well as the initiation of blood pressure lowering therapy and anticoagulation reversal in earlier time frames.