Topic Overview. A comprehensive metabolic panel is a blood test that measures your sugar (glucose) level, electrolyte and fluid balance, kidney function, and liver function.Glucose is a type of sugar your body uses for energy. Electrolytes keep your body's fluids in balance.t also controls the amounts of glucose, protein, and fat in the blood and releases substances that keep your immune system healthy. Your doctor may order a comprehensive metabolic panel as part of a regular health examination.