Ongoing evolution of prehospital medical care continues to advance beyond tactical field care scenarios in the consideration of prolonged field care. This is even more important to consider in theaters with extended evacuation times and limited local medical assets. The critical regulatory functions of electrolytes such as sodium, potassium, calcium, and glucose require medics operating in these environments to have a strong, fundamental knowledge of the principles, manifestations, and initial stabilization measures to aid their patients prior to, or in lieu of evacuation. Continued development and access to point of care testing in increasingly forward deployed settings further enables medics to perform these tasks. Here, we provide a brief review of these vital electrolytes, as well as additional kidney function evaluation considerations, to assist medics in their treatment efforts. Specific concerns for battlefield and atraumatic presentations are addressed.