Read Time: Scientists at the Walter Reed Army Institute for Research demonstrated the potential of a novel blood test for cathepsin B, a well-studied protein important to brain development and function, as an indicator for a range of disease states. Cathepsin B plays an important role in the body, regulating the metabolism, immune responses, degradation of improperly produced proteins and other functions. Under certain conditions, such as metastatic cancers, infections, trauma and neurological disease, cathepsin B production is upregulated. Recent research published by WRAIR researchers highlighted the potential of cathepsin B as an indicator, or biomarker, of the severity of traumatic brain injury.