Electrolytes (clinical analyzes)



Water constitutes about 60-70% of the body weight of an adult individual and mainly represents the liquid (solvent) in which other substances of greater consistency (solutes, organic and inorganic) are dissolved and in which all the main biochemical reactions take place indispensable for life.

Electrolytes are minerals found in body fluids (blood, urine and others) in the form of positive ions (cations), mainly sodium, potassium, calcium and magnesium, and negative ions (anions), mainly chlorides, bicarbonates and phosphates .

Electrolytes are important because through their electric charge they allow to:

  • send impulses in the body to facilitate the absorption of nutrients and the elimination of waste products
  • ensure osmotic balance
  • keep blood acidity (ph) levels stable (acid-base ratio)
  • keep blood pressure stable, the amount of fluids present in the body (water balance) and the fundamental functions of the cells

They also have effects on the excitability of the membranes of nerve cells and perform functions in various enzymatic reactions.

Normally, they are consumed through food and water.

There are many causes that can determine a change in their concentration in the blood: diseases that affect the amount of fluids in the body or that affect the lungs, kidneys, breathing or the ability to maintain metabolic balance (homeostasis).

The level of electrolytes in the blood can vary, for example, due to an unhealthy diet, dehydration or excess fluid in the body.

The search for electrolyte values ​​is a frequently prescribed test among the control analyzes (routine analysis) and detects the concentration in the blood of some of them (mainly sodium, potassium, chlorine and bicarbonate); their balance, in fact, is very important for the general well-being of the organism and their variation can create various disorders and be an indication of heart disease, lung disease, liver and kidney disease, diabetes. In particular, potassium together with sodium regulates the acid-base and hydro-saline balance, the functions of nerve and muscle cells, normalizing the heartbeat.

Measurement of the electrolyte level may be ordered in the presence of:

  • accumulation of fluids (edema)
  • cramps
  • nausea or vomiting
  • weakness
  • confusion
  • irregular heartbeat (cardiac arrhythmia)

The test also allows you to follow (monitor) the effects of the treatment of certain diseases over time, including high blood pressure (hypertension), heart failure, and liver and kidney diseases.

The test

The "examination (test) consists of a" laboratory analysis carried out by taking a small amount of blood from a vein in the arm. Fasting is recommended, although not necessary. The intake of drugs generally does not influence the result of the analysis; however, as some medicines may limit the body's absorption of electrolytes, it is important to tell your doctor what type of drug treatment you are taking to enable him to evaluate the results correctly.


The concentrations of electrolytes depend mainly on the elements introduced in the diet, their absorption, the amount of water present in the body, the amount of water eliminated by the kidneys and can undergo variations in relation to the presence of various diseases.In general, a malfunction of the kidneys can lead to a decrease in sodium and chlorine. On the other hand, an excessive loss of fluids can cause a significant increase in the concentration of potassium, chlorine and sodium.

Some diseases such as, for example, heart disease, kidney failure and diabetes can cause changes, even major ones, in the concentration of electrolytes:

  • sodium, a "high concentration (called hypernatremia or hypersodemia) is almost always due to an inadequate introduction of water and dehydration (also from vomiting or diarrhea); a low concentration (called hyponatremia or hyponatremia) is usually linked to a significant loss of sodium caused by other factors such as kidney disease and Addison's disease, excessive introduction of water or water retention, accumulation of fluids in the body (edema)
  • potassium, an increase (referred to as hyperkalaemia or hyperkalaemia) may be due to kidney failure, Addison's disease, diabetes, dehydration, excessive dietary introduction; a decrease (hypokalemia or hypokalaemia) may be linked to gastrointestinal disturbances (vomiting, diarrhea), insulin, insufficient dietary intake
  • chlorine, an increase in the blood (called hyperchloremia) usually indicates dehydration; a decrease (hypochloremia) occurs following diseases that also result in low concentrations of sodium in the blood (renal failure). It also occurs in cases of congestive heart failure, prolonged vomiting, Addison's disease, emphysema, or other chronic lung diseases
  • bicarbonate, if the concentration is higher or lower than normal, it means that the body has problems maintaining the "acid-base balance, that is to say the" set of mechanisms that it puts in place to maintain the level of acidity compatible with the performance of its functions.When the levels are low the cause can be chronic diarrhea, acidosis or ketoacidosis, kidney disease; if, on the other hand, they are very high it may be due to prolonged vomiting, lung diseases, alkalosis

The intake of certain medications can also cause an increase or decrease in the concentration of electrolytes, for example anabolic steroids, corticosteroids, laxatives, cough relievers and oral contraceptives can increase sodium concentration while diuretics can decrease sodium. concentration of sodium and potassium.

The alteration of only one of them may require a specific examination for each electrolyte.

It must always be borne in mind that the levels indicated as normal in the results of the analyzes may undergo small variations based on the minimum and maximum values ​​(range) used as a reference by the various laboratories. They will, however, be easily understood thanks to the indication present in the results sheet (report).

Since variations in the level of electrolytes can be caused by various diseases or disorders, it is always advisable to consult your doctor and, if necessary, the specialist for the reading and interpretation of the results.


MedlinePlus. Fluid and Electrolyte Balance (English)

MedlinePlus. Electrolyte Panel (English)

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