Electrolytes are minerals in your blood and other body fluids that carry an electric charge.

Electrolytes affect the amount of water in your body, the acidity of your blood (pH), your muscle function, and other important processes. You lose electrolytes when you sweat. You must replace them by drinking fluids.

Common electrolytes include:

• Calcium
• Chloride
• Magnesium
• Phosphorous
• Potassium
• Sodium

Electrolytes can be acids, bases, and salts.

They can be measured by laboratory studies of the blood in different ways. Each electrolyte can be ordered as a separate test, such as:

• Ionized calcium
• Serum calcium
• Serum chloride
• Serum magnesium
• Serum phosphorus
• Serum potassium
• Serum sodium

Note: Serum is the part of blood that doesn't contain cells.

Sodium, potassium, and chloride can also be ordered as part of an electrolyte panel or a basic metabolic panel.

The electrolytes - urine test measures electrolytes in urine. It usually measures the levels of calcium, chloride, potassium, or sodium.