Ubiquitin C-terminal Hydrolase-L1 and Glial Fibrillary Acidic Protein Tandem Brain Biomarker Test in the Prediction of CT Evident Brain Injury: a Prospective Evaluation in the Emergency Department.

Abstract

Patients with features of mild traumatic brain injury (mTBI) frequently present to the emergency department (ED) and often meet recognised criteria for CT head imaging. Observational studies suggest that use of a tandem ubiquitin C-terminal hydrolase-L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) brain biomarker test may significantly reduce need for CT scanning in this population, though data on patient flow are lacking. In a prospective evaluation in a UK population with mTBI a laboratory UCH-L1/GFAP test identified 21 of 89 (24%) patients as low-risk for CT-evident TBI with a sensitivity of 100% (95% CI 76-100%) and NPV of 100% (95% CI 85-100%). The median time to obtain a biomarker result from venesection was 88 minutes, similar to the time from CT request to report (89 minutes). However, those 68 (76%) patients with a positive biomarker result would all have required subsequent CT imaging, significantly prolonging ED length of stay and making incorporation into clinical pathways difficult. Availability of platforms that allow measurement of UCH-L1/GFAP in whole blood at the point-of-care may circumvent these problems in the future, and permit safe rationalisation of CT imaging in this population without compromising ED patient workflows.