Sodium

The Sodium test measures the concentration of sodium in the blood.

Sodium is an essential body electrolyte which, along with potassium, chloride, bicarbonate, etc., helps to maintain the normal fluid and pH balance in the body. It is also vital for cellular metabolism, and in the activity of nerves and muscles and transmission of impulses between them. Sodium is present in all body fluids and is found in highest concentration in the blood and extracellular fluid.

Sodium is supplied to the body principally through dietary salts (sodium chloride or NaCl), and a small portion of sodium is absorbed through other food items. The required portion is absorbed by the body and the remaining is excreted by the kidneys through urine. The body maintains a very narrow range of sodium concentration by three mechanisms:

·         Secretion of hormones natriuretic peptides and aldosterone to control sodium elimination through urine

·         Secretion of antidiuretic hormone (ADH), also called Vasopressin, to control the volume of water eliminated through urine

·         Induction of thirst

Any disruption in the abovementioned mechanisms gives rise to an imbalance in the concentration of sodium in the blood to produce Hyponatremia (low blood sodium concentration), or Hypernatremia (high blood sodium concentration). Both these conditions produce a number of symptoms and may even lead to death.