No handheld point-of-care (POC) device capable of determining the presence and extent of acute brain injury due to trauma or blast injury currently exists. Such a diagnostic device would decrease the incidence of over- and under-triage of TBI and would expedite administration of appropriate casualty care during forward operations. Although there are presently no objective, blood-based diagnostic tests for TBI, several candidate biomarkers indicative of cellular, functional, or tissue damage have been identified as possible diagnostic markers for the presence and severity of TBI. We will develop multiplexed, quantitative immunoassays for up to 8 different markers for use in blood and serum. The biomarker arrays will be developed in both bead and planar array formats and be tested using both spiked samples and banked samples obtained from TBI patients. Finally, the biomarker assay arrays will then be integrated into a COTS rapid biosensor platform that has already been validated for POC diagnostics in resource-limited situations.