Serum Electrolyte

The serum electrolyte test measures the following electrolytes:

• Sodium (Na+)

• Potassium (K+)

• Chloride (Cl-)

Electrolytes play an important role in a number of body functions like metabolism, neuromuscular functioning, maintaining hydration and pH (acid-base balance). Electrolytes also help in the entry of nutrients into the cells and removal of waste products from the cells. Electrolytes carry an electrical charge, either negative or positive and exist as dissolved salts in blood and body tissues. The Serum Electrolyte test measures the following important electrolytes:

Sodium (Na+)

Sodium is an essential body electrolyte which, along with potassium, chloride, bicarbonate, etc., helps to maintain the normal fluid and pH balance of 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 the body fluids. The highest concentration of sodium is found in blood and extracellular fluid.

Sodium is supplied to the body principally through dietary salt (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 above mentioned 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.

Potassium (K+)

Potassium is one of the essential body electrolytes along with sodium, chloride, bicarbonate, etc. As an electrolyte, potassium helps to regulate the amount of fluids present in the body and to maintain a correct pH balance. It performs a vital role in cellular metabolism and transport of nutrients and waste products in and out of cells. It is also essential in the transmission of nerve impulses to muscles and muscle activity.

Sufficient amount of potassium required by the body is absorbed from dietary sources, and the remaining unabsorbed potassium is excreted by the kidneys. The hormone called aldosterone maintains the body potassium level within a small normal range. Aldosterone acts on the nephrons present in the kidneys and activates a sodium-potassium pump which helps the body to reabsorb sodium and excrete potassium. This helps to maintain the potassium concentration in the blood within its normal range. Deviation of potassium concentration from its normal range gives rise to Hyperkalemia (high potassium level in blood), or Hypokalemia (low potassium level in blood). Both these conditions may produce a number of symptoms, and may even be fatal if not controlled.

Chloride (Cl-)

Chloride is an essential mineral which acts as an electrolyte along with potassium, sodium, bicarbonate, etc. It helps to maintain the normal fluid and electrolyte balance in the body. It also acts as a buffer to help maintain the pH balance of the body. It also plays essential roles in metabolism. Chloride is used by the stomach to produce hydrochloric acid (HCl) for digestion. Chloride is present in every body fluid. The highest concentration of chloride is found in blood and extracellular fluid (fluid present outside the cells).

Most of the chloride is supplied to the body through dietary salt (sodium chloride or NaCl), and a small portion 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 concentration of chloride in blood is maintained within a very narrow range by the body. Its increase or decrease is directly correlated with the sodium levels.