The Electrolyte Panel Test
The electrolyte panel test is one of the most commonly ordered tests for diagnostic purposes. Imbalances in electrolytes occur in numerous chronic and acute diseases includes edema, diabetes, high blood pressure and heart disease. The components of the electrolyte panel test include sodium, potassium, chloride and bicarbonate (CO2). Abnormalities in one or more of the electrolye components can greatly aid in diagnosis of acute condition and evaluation of existing, chronic conditions.
Electrolytes are part of basic metabolic panels and comprehensive metabolic panels, which are screening tests ordered in evaluation of overall health. These tests are ordered when patients present with symptoms including nausea and vomiting, weakness and lethargy, or irregularities in heart beat.
How is Electrolyte Testing Performed
Electrolytes are ionic in nature, meaning that they carry either a positive or negative charge. When sodium chloride is dissolved in water, the salt breaks down into sodium and chloride. Sodium is positively charged and chloride is negatively charged. Both have an electro potential based on the amount of sodium and chloride present and the corresponding charge.
Measurement of electrolytes takes place using Specific Ion Electrode, also known as Ion Selective Electrode. The electrode is usually a membrane specific for the type of ion being measured. The amount of ion present is directly related to the increase in potential as ion cross the membrane. This is measured using an internal voltage meter.
The Relationship of Aldosterone and Electrolytes
Aldosterone is a hormone that is produced by the adrenal glands, located near the kidneys. The primary role of aldosterone in relationship to electrolytes is a balance of the sodium and potassium levels in the body. This delicate balance of sodium and potassium is important for maintaining a healthy blood pressure as well as controlling the amount of fluids in the body. Abnormal levels of aldosterone can affect the balance between sodium and potassium. Increased sodium causes the body to retain fluids and potassium is excreted by the kidneys resulting in low potassium levels.
Understanding Electrolyte Test Results
The electrolyte panel test results are effected by the type of diet, the amount of water taken in and the overall functioning of the kidneys. Values may change slightly according to diet and the amount of liquid, but abnormal or impaired kidney function can have a dramatic effect on electrolyte test results.
Increased sodium results in edema. Generally potassium levels are decreased under edemic conditions. Decreased sodium can result from kidney, liver or heart disease. Increased potassium indicates kidney disease and can result in heart arrhythmia. Chloride levels generally correspond to sodium levels. Chloride can be increased in diarrhea and other conditions resulting in dehydration. Chloride may be decreased in kidney disease or diseases of the adrenal glands.
Bicarbonate increases under conditions of oxygen deprivation. Difficulty breathing can result in a build up of carbon dioxide which can lead to an acid/alkaline imbalance. Further testing requires blood gas testing with an arterial stick to determine the oxygencarrying capacity of the blood.
Evaluation of electrolyte values requires consideration of patient symptoms as well as history and medication usage.