An electrolyte panel is a group of tests that measure the levels of electrolytes in the blood. Electrolytes are substances in the body that help balance fluids and help muscles and nerves function properly. Common electrolytes tested in an electrolyte panel include sodium, potassium, and chloride.The electrolyte panel is typically performed by drawing a small sample of blood from a vein in the arm, using a needle and a tube. An electrolyte panel is often ordered as part of a routine health examination or when a person has symptoms that may be related to a medical condition. It is used to help diagnose and monitor a variety of medical conditions and to assess the effectiveness of treatment. An electrolyte panel may also be ordered along with other tests as part of a comprehensive metabolic panel or a complete blood count.