Proper diagnosis of mild inflicted traumatic brain injury (ITBI) is difficult; children often present without a history of trauma and with nonspecific symptoms, such as vomiting. Previous studies suggest that biomarkers may be able to screen for brain injury in this population, but these studies focused on only a few biomarkers. We hypothesized that using multiplex bead technology we would be able to identify multiple differences in the serum biomarker profile between in children with ITBI and those without brain injury. We compared the concentrations of 44 serum biomarkers in 16 infants with mild ITBI and 20 infants without brain injury. There were significant group differences in the concentrations of nine of the 44 markers. Vascular cellular adhesion molecule (VCAM) (p Ͻ 0.00) and IL-6 (IL-6) (p Ͻ 0.00) had the most significant group differences; IL-6 was higher after ITBI, whereas VCAM was lower. Using VCAM and IL-6 in classification algorithms, we could discriminate the groups with a sensitivity and specificity of 87% and 90%, respectively. The results suggest significant changes in the serum biomarker profile after mild ITBI. Future research is needed to determine whether these biomarkers can screen for brain injury in infants with nonspecific symptoms. Proper diagnosis of ITBI is often difficult even for experienced, astute physicians because caretakers rarely provide a history of trauma (4,5), children present with nonspecific symptoms, such as vomiting or fussiness (6) and physical examination can be normal (7,8). As a result, misdiagnosis is common and can have catastrophic medical consequences (9,10). The importance of timely diagnosis of ITBI cannot be overemphasized: if not recognized, child abuse is an escalating form of trauma that often ends in death or disability (11).The frequency with which ITBI is misdiagnosed and the resulting morbidity and mortality are compounded by the lack of a well-established screening test to help physicians identify children who might benefit from evaluation with cranial computed tomography (CT). We previously reported on the possible use of serum biomarkers as screening tools for infants at increased risk of missed ITBI-infants without a history of trauma and with nonspecific symptoms (12-15). We focused on three well-established and relatively brain-specific markers: neuron-specific enolase, S100B, and myelin-basic protein.Our study evaluating these markers as screening tools for ITBI in high-risk infants showed that a combination of neuronspecific enolase and myelin-basic protein was 79% sensitive and 70% specific for brain injury (14). Contrary to previous literature in adults and older children, S100B was not specific for brain injury in infants.Biomarker concentrations in our previous studies have been measured using ELISA. ELISA allows for measurement of only one biomarker at a time and requires up to 100 L of serum for each biomarker. In young children, it is difficult to collect large sample volumes and 100 L may be the entire sample.Multiplex bead...