What is Serum Electrolyte?
Electrolytes are minerals which are present in the blood and body tissues. They are essential for metabolism, for proper nerve and muscle functioning, for maintenance of proper water balance, and proper blood pH (acid-base balance). The serum electrolyte test includes a group of tests to measure the following electrolytes: Sodium (Na+), Potassium (K+) and Chloride (Cl-).
Why is Serum Electrolyte done?
The Serum Electrolyte Test is performed:
· As a part of a routine health checkup
· To assess problems in the water and pH balance of the body
· As a part of the checkup to diagnose kidney diseases
· Upon the appearance of symptoms indicating neuromuscular conditions like muscular weakness, irregular heartbeats or cardiac arrhythmia, etc.
· At regular intervals to monitor the progress of condition and treatment efficacy while undergoing treatment for hypertension, kidney diseases, and metabolic acidosis
· To monitor patients who are receiving diuretic therapy, intravenous fluids, or dialysis
What does Serum Electrolyte Measure?
The serum electrolyte test measures the following electrolytes:
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 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 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 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.
Interpreting Serum Electrolyte results
The normal range of serum electrolytes may vary from lab to lab.
Normal range: 135 to 145 mmol/L
Hyponatremia: Below 135 mmol/L
Hypernatremia: Above 145 mmol/L
Sodium concentration in the body is maintained within a narrow normal range between 135 mmol/L and 145 mmol/L.
Hyponatremia or low blood sodium indicates that sodium concentration lies below the normal range.
Hypernatremia or high blood sodium indicates that sodium concentration lies above the normal range.
Normal range: 3.5 to 5.0mmol/L (136.5 to 195μg/ml approx.)
Hypokalemia: Below 3.5mmol/L (Less than 136.5μg/ml approx.)
Hyperkalemia: Above 5.0mmol/L (Above 195μg/ml approx.)
Potassium concentration in the body is maintained within a narrow normal range between 3.5mmol/L and 5.0mmol/L.
Hypokalemia or low blood potassium indicates that potassium concentration lies below the normal range.
Hyperkalemia or high blood potassium indicates that potassium concentration lies above the normal range.
Normal reference range:
Adults: 98 to 106 mEq/L (milliequivalents per liter)
Children: 90 to 110 mEq/L
Newborn: 96 to 106 mEq/L
Higher than normal chloride level is called Hyperchloremia.
Lower than normal chloride level is called Hypochloremia.
Answers to Patient Concerns & Frequently Asked Questions (FAQs) about Serum Electrolyte
Frequently Asked Questions about Serum Electrolyte
Tests Included (3 tests)