This pilot study sought to determine if creatine kinase isoenzyme BB (CK-BB) levels might serve as a biological marker of injury severity in mild TBI (mTBI). This was a retrospective study of 64 soldiers with suspected mTBI seen in a combat support hospital in Mosul between March and August of 2007. Four of the 64 total samples were positive for CK-BB. One major trauma patient had a negative CK-BB. This yields a sensitivity of 11% and a specificity of 97%. Military Acute Concussion Evaluation (MACE) scores collected also did not appear to reflect extent of injury. Although the low sensitivity of CK-BB from this study does not support its use as an early marker of suspected mTBI, the result is not conclusive given the small sample and the possibility of isoenzyme degradation during transport. Although limited, the data collected on MACE scores warrant additional evaluation of whether this measure is clinically relevant.