In body tissues and blood, electrolytes are found in the form of dissolved salts and minerals. The main electrolytes include sodium, potassium, bicarbonate, and chloride. Calcium, magnesium, phosphate, sulphate, organic acids and proteins are other electrolytes found in body fluids. Electrolytes help move nutrients into body’s cells and help move waste out of the body’s cells. Electrolytes maintain a healthy water balance, and…In body tissues and blood, electrolytes are found in the form of dissolved salts and minerals. The main electrolytes include sodium, potassium, bicarbonate, and chloride. Calcium, magnesium, phosphate, sulphate, organic acids and proteins are other electrolytes found in body fluids. Electrolytes help move nutrients into body’s cells and help move waste out of the body’s cells. Electrolytes maintain a healthy water balance, and help stabilise the body’s acid/base (pH) level. Electrolytes are usually measured as part of a renal profile which measures the main electrolytes in the body, sodium (Na+), potassium (K+), together with creatinine and/or urea, and may occasionally include chloride (Cl-) and/or bicarbonate (HCO3-). Calcium, magnesium and phosphate are measured when imbalances in their concentrations are suspected. Most of the body’s sodium is found in the extracellular fluid (ECF), outside of the body’s cells, where it helps to regulate the amount of water in your body. Potassium is found mainly inside the body’s cells. A small but vital amount of potassium is found in the plasma, the liquid portion of the blood. Monitoring potassium is important as small changes in the plasma potassium concentration can affect the heart’s rhythm and ability to contract (pump). Chloride travels in and out of the cells to help maintain electrical neutrality, and its level usually mirrors that of sodium. The primary role of bicarbonate, which is excreted and reabsorbed by the kidneys, is to help maintain a stable pH level and, secondarily, to help maintain electrical neutrality. Your diet provides sodium, potassium, and chloride and other electrolytes. In order to maintain a “normal” electrolyte concentration your kidneys excrete them in urine. Your lungs provide oxygen and regulate carbon dioxide which is in balance with the bicarbonate level in plasma. The balance of these chemicals is an indication of the functional well-being of several basic body functions, including those performed by the kidneys and heart. A related “test” is the anion gap (see below ‘What is anion gap?’) which is actually a calculated value. It reflects the difference between the positively charged ions (called cations) and the negatively charged ions (called anions). How is the sample collected for testing? A blood sample is taken by needle from a vein in the arm. In some cases, a urine sample may also be collected. This allows comparison of the concentration of electrolytes in the blood to the concentration of the electrolytes in the urine. This can identify inappropriate loss of the electrolyte when blood concentration is low or inappropriate retention of the electrolyte when blood concentration is high. See MoreSee Less
