Ubiquitin CTerminal HydrolaseL1 (UCHL1) in Prediction of Computed Tomography Findings in Traumatic Brain Injury; a MetaAnalysis

Introduction: Ubiquitin Cterminal hydrolaseL1 (UCHL1) is one of the promising candidates, with an acceptable diagnostic value for predicting head computed tomography (CT) scan findings. However, there has been a controversy between studies and still, there is no general overview on this. Therefore, the current systematic review and metaanalysis attempted to estimate the value of UCHL1 in predicting intracranial lesions in traumatic brain injury.Methods: Two independent reviewers screened records from the search of four databases Medline, Embase, Scopus and Web of Science. The data were analyzed in the STATA 14.0 statistical program and the findings were reported as a standardized mean difference (SMD), summary receiver performance characteristics curve (SROC), sensitivity, specificity, and diagnostic odds ratio with 95% confidence interval (95% CI).Results: Finally, the data of 13 articles were entered into the metaanalysis. The mean serum level of UCHL1 was significantly higher in patients with CTpositive than in TBI patients with CT negative (SMD = 1.67, 95% CI: 1.12 to 2.23, I2 = 98.1%; p lt;0.0001). The area under the SROC curve for UCHL1 in the prediction of intracranial lesions after mild TBI was 0.83 (95% CI: 0.80 to 0.86). Sensitivity, specificity and diagnostic odds ratio of serum UCHL1 was 0.97 (95% CI: 0.92 to 0.99), 0.40 (95% CI: 0.30 to 0.51) and 19.37 (95% CI: 7.25 to 51.75), respectively. When the analysis was limited to assessing the serum level of UCHL1 within the first 6 hours after mild TBI, its sensitivity and specificity increased to 0.99 (95% CI: 0.94 to 1.0) and 0.44 (95% CI: 0.38 to 0.052), respectively. In addition, the diagnostic odds ratio of 6hour serum level of UCHL1 in the prediction of intracranial lesions was 680.87 (95% CI: 50.50 to 9197.97).Conclusion: Moderate level of evidence suggests that serum/plasma levels of UCHL1 have good value in prediction of head CT findings. It was also found that evaluation of serum/plasma level of UCHL1 within the first 6 hours following TBI would increase its predictive value. However, there is a controversy about the best cutoffs of the UCHL1.