A high-performance core laboratory GFAP/UCH-L1 test for the prediction of intracranial injury after mild traumatic brain injury.

BACKGROUND

A glial fibrillary acidic protein (GFAP) and ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) blood biomarker panel can reliably eliminate the need to perform a head computed tomography (CT) scan in selected patients with traumatic brain injury (TBI). Currently, this FDA cleared panel can be run both on a core laboratory platform or a hand-held single-sample point of care platform. This study examined test characteristics of the panel as analyzed on a core lab-based fast high-throughput platform.

METHODS

This secondary analysis of clinical data and banked blood samples obtained for the ALERT-TBI study included patients ≥18 years old with nonpenetrating head injury, a presenting Glasgow Coma Scale score 9-15, and a head CT was indicated. Included were patients with a GCS 13-15 who had sufficient banked blood for analysis. Test characteristics of the biomarker panel were determined relative to head CT findings for traumatic intracranial injury.

RESULTS

Among the 1899 included subjects, mean age was 49.1 yrs. (18 to 98 yrs), 56.5 % male, and 70.6 % were Caucasian. The most common mechanism of injury was a fall (51.9 %) and 94.1 % presented with a GCS of 15. Head CT was positive for traumatic intracranial injury in 120 patients (6.3 %) of which the biomarker panel was a false negative in four patients. Sensitivity (95 % confidence interval) of the biomarker panel was 96.7 (91.7, 98.7), specificity 40.1 (37.8, 42.4), negative predictive value 99.4 (98.6, 99.8), and the negative likelihood ratio was 0.08 (0.03, 0.22).

CONCLUSIONS

The biomarker panel, measured on this core lab-based fast high-throughput platform, had high sensitivity and negative predictive values. The core laboratory platform has the advantage of speed and the ability to analyze multiple samples simultaneously suggesting additional utility when there is high need for CT imaging such as mass casualty or emergency department volume overload situations.