Role of Salivary Biomarkers in Predicting Significant Traumatic Brain Injury: An Exploratory Study

The highest rates of traumatic brain injury (TBI)-related morbidity and mortality occur in young children and adolescents. The objective of this study was to describe the levels of 3 biomarkers (S100B, glial fibrillary acidic protein, neuron-specific enolase) in saliva of children with TBI requiring inpatient admission at a pediatric trauma center and compare these levels in children without TBI.

A convenience sample of 24 children aged 0 to 18 years, presenting with acute isolated TBI, was enrolled prospectively. The non-TBI comparison groups consisted of patients with medical complaints and musculoskeletal injuries only. Salivary specimens were collected, and biomarkers were measured using quantitative enzyme-linked immunosorbent assay method. Demographic, clinical data, and brain imaging findings were obtained.

Seventy-four children were enrolled. Twenty-four had TBI (mean age, 5.07 years; SD, 4.8 years); 14 subjects (58.3%) with TBI were found to have significant traumatic brain injury (SBI) on computed tomography scan. S100B levels were significantly higher in TBI group compared with those with musculoskeletal injury only (median, 113.2 pg/mL vs 18 pg/mL; P = 0.021). Area under the receiver operating characteristic curve for S100B in predicting SBI was 0.675; the optimum threshold for S100B to achieve the optimum sensitivity and specificity of SBI was at 86.9 pg/mL for SBI versus no injury group.

S100B levels in saliva were higher in children with TBI and may be predictive of SBI identified by presence of computed tomography abnormalities. Larger studies are needed to replicate our findings in using a noninvasive diagnostic measure for children with TBI and SBI.