An Electrolytes test is a simple blood test that measures important salts in your body, such as sodium, potassium, and chloride. These help regulate water balance, nerve signals, muscle function, and heart rhythm. Imbalance can happen with dehydration, heat, vomiting, loose motions, kidney problems or severe illness. Symptoms may include weakness, muscle cramps, confusion, irregular heartbeat and, in severe cases, fits. This test helps your doctor quickly find and correct disturbances in the body’s salt and water balance, often in emergencies or during hospital treatment.