Glial Fibrillary Acidic Protein in Blood as a Diagnostic Method for Traumatic Brain Injury: A Systematic Review and Meta-Analysis

Introduction: Traumatic brain injury (TBI) is a leading cause of morbidity and mortality worldwide. Glial fibrillary acidic protein (GFAP) has been proposed as a blood-based diagnostic biomarker for TBI, but its clinical utility remains uncertain. This meta-analysis assessed the diagnostic accuracy of GFAP in identifying TBI. Methods: A systematic search was conducted in biomedical databases for studies published between 2019 and 2024. Clinical trials with adequate sample sizes and standardized GFAP detection methods were included. Sensitivity, specificity, and predictive values were analyzed using statistical models to evaluate diagnostic accuracy. Results: Seven studies with a total of 3,209 patients were included. The overall sensitivity of GFAP was 0.91 (95% CI: 0.83–0.96), demonstrating a high capacity to detect TBI. However, specificity was moderate (0.61, 95% CI: 0.48–0.73), indicating a higher rate of false positives. The summary ROC curve confirmed a good general diagnostic performance but highlighted limitations in differentiating TBI from other neurological conditions. Conclusions: GFAP exhibited high sensitivity as a diagnostic biomarker for TBI, making it a useful tool for early detection. However, its low specificity suggests the need for combination with other biomarkers to improve diagnostic accuracy.