The Centers for Disease Control and Prevention estimates almost two million traumatic brain injuries (TBIs) occur annually in the U.S., resulting in nearly $80 billion of economic burden. Despite its prevalence, current TBI diagnosis methods mainly rely on cognitive assessments vulnerable to subjective interpretation, thus highlighting the critical need to develop effective unbiased diagnostic methods. The presented study aims to assess the feasibility of a rapid multianalyte TBI blood diagnostic. Specifically, two electrochemical impedance techniques were used to evaluate four biomarkers: glial fibrillary acidic protein, neuron specific enolase (NSE), S-100β, and tumor necrosis factor-α. First, these biomarkers were characterized in purified solutions (detection limit, DL = 2-5 pg/mL), then verified in spiked whole blood and plasma solutions (90% whole blood DL = 14-67 pg/mL). Finally, detection of two of these biomarkers was validated in a controlled cortical impact model of TBI in rats, where a statistical difference between NSE and S-100β concentrations differed several days postinjury (p = 0.02 and p = 0.06, respectively). A statistical difference between mild and moderate injury was found at the various time points. The proposed diagnostic method enabled preliminary quantification of TBI-relevant biomarkers in complex media without the use of expensive electrode coatings or membranes. Collectively, these data demonstrate the feasibility of using electrochemical impedance techniques to rapidly detect TBI biomarkers and lay the groundwork for development of a novel method for quantitative diagnostics of TBI.