9 Banyan BT Blood Test Predicts Absence of Intracranial Injuries After Mild Traumatic Brain Injury: Results of the Pivotal ALERT-TBI Multicenter Study

Abstract

To validate a blood test combining ubiquitin C-terminal hydrolase-L1 (UCH-L1) and glial fibrillary acidic protein (GFAP), at pre-determined cut-off values, to predict traumatic intracranial injuries on head CT scan acutely after mild traumatic brain injury (TBI). A total of 1977 TBI subjects were prospectively enrolled among 22 emergency departments in the US and Europe; 1942 (98.2%) had mild TBI (Glasgow Coma Scale [GCS] score 13-15), and 1828 (92.5%) had GCS of 15. Subjects presenting to the ED with suspected TBI underwent blood draw and head CT within 12 hours of injury. Three board-certified neuroradiologists conducted an independent, blinded review of each CT scan to determine whether it was CT-positive or CT-negative with respect to acute intracranial lesions. UCH-L1 and GFAP were measured in serum and analyzed using pre-specified cutoff values of 327pg/mL and 22pg/mL, respectively. UCH-L1 and GFAP assay results were combined into a single brain trauma indicator (BTI) test result that was correlated with CT-detected intracranial injury. Among mild TBI subjects, the mean age was 48.9 years; 56.6% were male, 30.3% were non-white, and the most frequent injury mechanisms were falls (51.3%) and motor vehicle crashes (34.6%). In mild TBI subjects, the test had sensitivity of 0.975 (95% CI: 0.93, 1.0) and negative predictive value (NPV) of 0.996 (95% CI: 0.99, 1.0). Among the subset of mild TBI subjects with a GCS of 15 the test had sensitivity of 0.968 (0.91, 0.99) and NPV of 0.995 (0.99, 1.0). Test specificity was 0.366 (0.34, 0.39) for mild TBI and 0.370 (0.35, 0.39) for those with a GCS of 15. The results demonstrated the Banyan BTI™ test is characterized by both high sensitivity and NPV, which supports its potential clinical role for ruling out the need for a CT scan in ED patients with suspected mild TBI and a negative test result.