Electrolytes

Also known as: Lytes

Formal name: Electrolyte Panel

Related tests: Sodium, Potassium, Chloride, Bicarbonate (or total CO2), CMP, BMP

The Test

How is it used?
When is it ordered?
What does the test result mean?
Is there anything else I should know?

How is it used?

The electrolyte panel is frequently ordered as part of a routine physical, either by itself or as components of a basic metabolic panel or comprehensive metabolic panel. It is used to screen for an electrolyte or acid-base imbalance and to monitor the effect of treatment on a known imbalance that is affecting bodily organ function. Since electrolyte and acid-base imbalances can be present with a wide variety of acute and chronic illnesses, the electrolyte panel is frequently ordered for hospitalized patients and those who come to the emergency room.

If a patient has a single electrolyte that is high or low, such as sodium or potassium, the doctor may order repeat testing of that individual electrolyte, monitoring the imbalance until it resolves. If a patient has an acid-base imbalance, the doctor may order blood gas tests, which measure the pH and oxygen and carbon dioxide levels in an arterial blood sample, to help evaluate the severity of the imbalance and monitor its response to treatment.

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When is it ordered?

It may be ordered as part of a routine screening or as a diagnostic aid when a patient has symptoms, such as edema, nausea, weakness, confusion, or cardiac arrhythmias. It is frequently ordered as part of an evaluation when a patient has an acute or chronic illness and at regular intervals when a patient has a disease or condition or is taking a medication that can cause an electrolyte imbalance. Electrolytes are commonly used to monitor treatment of certain problems, including high blood pressure (hypertension), heart failure, and liver and kidney disease.

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What does the test result mean?

Electrolyte levels are affected by how much is taken in through your diet, the amount of water in your body, and the amount of electrolytes excreted by your kidneys. They are also affected by compounds such as aldosterone, a hormone that conserves sodium and increases the loss of potassium, and natriuretic peptides, which increase renal losses of sodium.

In specific disorders, one or more electrolytes may be in an abnormal concentration. Your doctor will look at the overall balance but is especially concerned with your sodium and potassium levels. People whose kidneys are not functioning properly, for example, may retain excess fluid in the body, diluting the sodium and chloride so that they fall below normal concentrations. Those who experience severe fluid loss may show an increase in potassium, sodium, and chloride. Some forms of heart disease, muscle and nerve problems, and diabetes may also have one or more abnormal electrolytes.

Knowing which electrolytes are out of balance can help your doctor to determine the cause and treatment to restore proper balance. If left untreated, electrolyte imbalance can lead to dizziness, cramps, irregular heartbeat, and possibly death.

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Is there anything else I should know?

Depending on which electrolyte(s) is out of balance and the extent of that change, treatment may involve changing your diet to lower salt intake, increasing fluids to dilute the electrolyte concentration, taking diuretics, and medicating the imbalance. Once a treatment has begun, you may be asked to get regular testing to determine how well the treatment worked and to make sure the imbalance does not reoccur.

Potassium levels can be falsely elevated by several different specimen-collection or –processing errors. If there are any questions as to how your blood was collected, your doctor may request that the test be repeated to verify results.

Certain drugs such as anabolic steroids, corticosteroids, laxatives, cough medicines, and oral contraceptives may cause increased levels of sodium. Other drugs such as diuretics, carbamazepine, and tricyclic antidepressants may cause decreased levels of sodium.

Drugs that affect sodium blood levels will also cause changes in chloride. In addition, swallowing large amounts of baking soda or substantially more than the recommended dosage of antacids can also cause low chloride.

Some drugs may increase bicarbonate (total CO2) levels including: fludrocortisone, barbiturates, bicarbonates, hydrocortisone, loop diuretics, and steroids.   Drugs that may decrease bicarbonate (total CO2) levels include methicillin, nitrofurantoin, tetracycline, thiazide diuretics, and triamterene.

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