ABSTRACT NUMBER: ESOC2026A1561 PLASMA NEUROFILAMENT LIGHT CHAIN AND GLIAL FIBRILLARY ACIDIC PROTEIN IN THE DIFFERENTIAL DIAGNOSIS OF ACUTE VERTIGO IN THE EMERGENCY DEPARTMENT

Abstract Background and aims Distinguishing posterior circulation stroke (PCS) from other causes of acute vertigo can be challenging. Blood biomarkers such as neurofilament light chain (NfL) and glial acidic fibrillary protein (GFAP) have been associated with (even small) stroke lesions and could therefore support selection for imaging and inpatient evaluation in acute vertigo patients. Methods This prospective, observational study included consecutive patients with acute vertigo from a neurological emergency department. All patients received neurological examination, laboratory testing and brain imaging. Plasma NfL (pNfL) and GFAP (pGFAP) were measured using Single Molecule Array (SIMOA) technique. pNfL and pGFAP Z-scores were compared between PCS patients and patients with non-central vertigo causes. Results 102 patients were included (mean age 57.9 years, 57.8% female). pNfL Z-scores were higher in PCS compared to non-central vertigo patients (median 2.1, IQR 1.5 versus median 0.7, IQR 1.9; p=0.004). A pNfL Z-score≥1.0 was associated with PCS (OR 8.8, 95%-CI 2.4-32.7), yielding a sensitivity of 84.2%, specificity of 62.4% and negative predictive value of 94.6%. pGFAP Z-scores were higher in PCS than in non-central vertigo patients (median 1.3, IQR 2.8 versus median 0.6, IQR 1.5; p=0.016). A pGFAP Z-score≥1.0 was associated with PCS (OR 3.5, 95%-CI 1.3-9.8), yielding a sensitivity of 57.9%, specificity of 71.8% and negative predictive value of 88.4%. Associations remained robust after correcting for symptom duration. Conclusions pNfL and pGFAP levels were higher in PCS compared to patients with non-central causes of vertigo. With its high negative predictive value, pNfL appears especially clinically useful to rule out PCS in acute vertigo. Conflict of interest Nothing to disclose regarding this abstract.