LAUSR

GFAP is FDA-cleared to determine need for head CT within 12 hours after mild TBI (GCS 13-15); S100B serves this function in Europe. This Phase 1 Biomarker Cohort analysis of the multicenter, observational TRACK-TBI study compares GFAP's diagnostic performance, measured on a rapid point-of-care platform, against S100B to predict intracranial abnormalities on CT within 24 hours postinjury across the spectrum of TBI (GCS 3-15). Head CT scan performed in TBI subjects and blood was collected for all consenting subjects presenting to 18 U.S. trauma centers. Plasma was analyzed on a point-of-care device prototype assay for GFAP and serum was analyzed for S100B. In 1359 patients with TBI (GCS 3-15), mean (SD) age = 40.1 (17.0) years; 68% were male. Plasma GFAP levels were significantly higher in CT+ TBI subjects (median=1358pg/ml, IQR:472-3803) compared with CT- TBI subjects (median=116pg/ml, IQR:26-397) and compared with orthopedic trauma controls (N=122; median=13pg/ml, IQR: 7-20), p<0.001. Serum S100B levels were likewise higher in CT+ TBI subjects (median=0.17ug/l, IQR:0.09-0.38) compared with CT- TBI subjects (median=0.10ug/l, IQR:0.06-0.18), p<0.001. Receiver operating characteristics curves were generated for prediction of intracranial injury on admission CT scan; AUC for GFAP was significantly higher than for S100B in the same cohort (GFAP AUC - 0.85, 95% CI 0.83-0.87; S100B AUC - 0.67, 95% CI 0.64-0.70; p<0.001). GFAP, measured on a point-of-care platform prototype assay, has high discriminative ability to predict intracranial abnormalities on CT scan in patients with TBI across the full injury spectrum of GCS 3 -15 through 24 hours postinjury. GFAP substantially outperforms S100B.