Glial fibrillary acidic protein appears to be a candidate biomarker for detecting traumatic intracranial lesions on head CT after mild to moderate head trauma in youth, a study showed.
Previous studies have found that head CT scans in children less than 5 years old may contribute to the risk for brain cancer and leukemia because children are more sensitive to ionizing radiation. Ninety-nine different pediatric biomarkers have been researched for traumatic brain injury (TBI); some studies have indicated glial fibrillary acidic protein (GFAP) may be a promising biomarker for mild to moderate TBI in adults.
Dr. Linda Papa of the department of emergency medicine at Orlando Regional Medical Center and colleagues compared the GFAP level in the serum of children and youth evaluated for mild to moderate TBI with pediatric trauma patients without brain injury to see how these levels were related to evidence of traumatic lesions on head CT. Their results were published in Academic Emergency Medicine (2015 Nov;22[11]:1274-82. doi: 10.1111/acem.12795).
They conducted a prospective cohort study of 197 children and youth who presented with a Glasgow Coma Scale (GCS) score of 9-15 after blunt head trauma. The 60 control patients included those without head trauma and a GSC score of 15. A head CT scan was obtained in 152 patients, with 11% demonstrating traumatic intracranial lesions. Serum samples were drawn within 6 hours of injury, at a mean 3.3 hours in those with head injury and 4.1 hours in those without head injury.
Children with traumatic intracranial lesions on CT scan had higher median GFAP levels (1.01, interquartile range = 0.59-1.48), compared with those without lesions on CT (0.18, IQR = 0.06-0.47).
When GFAP was used to detect traumatic lesions on head CT, the area under the receiver operating characteristic curve (AUC) was 0.82 (95% confidence interval, 0.71-0.93); it was 0.80 (95% CI, 0.68-0.92) for those with a GCS of 15, and 0.83 (95% CI, 0.56-1.00) in those younger than 5 years old.
Using a cutoff level of 0.15 ng/mL for GFAP, Dr. Papa and colleagues noted a negative predictive value of 98%, a specificity of 47%, and a sensitivity of 94% for detecting intracranial lesions.
Several limitations to the study included not having research assistants available to enroll participants 24/7, a lack of long-term outcome data, and a small cohort without any participants requiring neurosurgical intervention.
The next steps would involve clinical validation with a large, multicenter study.
This study was supported by an award from the National Institute of Neurological Disorders and Stroke. Dr. Papa reported consulting for Banyan Biomarkers.