Over 2 million people suffer from mild traumatic brain injury (mTBI) each year. Predicting symptoms of mTBI and the characterization of those symptoms has been challenging. Biomarkers that correlate clinical symptoms to disease outcome are desired to improve understanding of the disease and optimize patient care. BMX, a member of the TEC family of nonreceptor tyrosine kinases, is upregulated after traumatic neural injury in a rat model of mTBI. The objective of this investigation was to determine if BMX serum concentrations can effectively be used to predict outcomes after mTBI in a clinical setting. A total of 63 patients with mTBI (Glasgow Coma Score [GCS] between13-15) were included. Blood samples taken at the time of hospital admission were analyzed for BMX. Data collected included demographic and clinical variables. Outcomes were assessed using the Dizziness Handicap Inventory (DHI) questionnaire at baseline and 6 weeks post-injury. The participant was asssigned to 'case group' if the subject's complaints of dizziness became worse at 6th week assessment; otherwise, the participant was assigned to 'control group '. A receiver operating characteristic (ROC) curve was constructed to explore BMX level. Significant associations were found between serum levels of BMX and dizziness. Areas under the curve (AUCs) for prediction of change in DHI post-injury were 0.76 for total score, 0.69 for physical score, 0.65 for emotional score and 0.66 for functional score. Specificities were between 0.69 and 0.77 for total score and emotional score, respectively. Therefore, BMX demonstrates potential as a candidate serum biomarker of exacerbating dizziness after mTBI.