An electrolyte panel is a group of blood tests that measures electrolyte levels to assess the general functioning of the patient’s organ systems. Electrolytes are minerals that are found naturally in the body and help regulate a number of functions. Electrolytes that are typically measured include potassium, chloride and sodium. Carbon dioxide, a waste product, is often included in the electrolyte panel. This can be measured in the blood in the form of bicarbonate. Other substances that are sometimes measured include calcium, magnesium and phosphorous, although these are not part of the standard electrolyte panel. The results of an electrolyte panel can help the physician make a diagnosis or help monitor the progress of treatment with medications.

Patients need to inform their physician of all prescription medications, over-the-counter medications, herbal remedies and vitamin supplements they may be taking because there is a wide variety of substances (e.g., birth control pills) that can affect the results of these tests. Patients also need to follow their physician’s orders carefully regarding the food, drink or medications that can be taken or should be avoided before the test.

Electrolytes are substances found throughout the body in varying concentrations. They move between locations to restore balance when needed. Electrolytes typically measured during an electrolyte panel include potassium, chloride and sodium. Additionally, the metabolic waste product carbon dioxide, measured as bicarbonate, is usually included as part of the electrolyte panel. Other substances that may be measured include calcium, magnesium and phosphorous.

When dissolved in a solution such as blood, electrolyte molecules split into ions (electrically charged particles) that allow the solution to conduct electricity. Because they are electrical conductors, electrolytes play an important role in many body processes, such as controlling fluid levels, acid/base balance, nerve conduction, blood clotting and muscle contraction (including that of the heart).

Electrolyte imbalance can cause serious problems such as dehydration, nausea, vomiting and fever. Over the long term, an electrolyte imbalance can contribute to heart disease, kidney failure, eating disorders and disorders of the endocrine system (glands).

An electrolyte panel is a group of blood tests that measures electrolyte levels to assess the general functioning of the patient’s organ systems. Electrolytes are found throughout the body in varying concentrations. They move between locations to restore balance when needed and regulate a number of functions, including fluid levels, heart rhythm and muscle contraction. In addition, electrolytes help the body maintain a normal pH level. Testing electrolyte levels in the blood can therefore provide physicians with valuable information about what chemical imbalances are occurring in the body.

Electrolyte testing is performed as part of a basic evaluation and diagnosis, but it may also be used to monitor the progress of treatment because many medications affect electrolyte balances within the body. For this purpose, regular testing may be required for some conditions.

An electrolyte panel typically includes blood levels of the following electrolytes:

Additionally, calcium, phosphorous and magnesium may sometimes be tested at the same time, although these measurements are not part of a standard electrolyte panel.

More than 98 percent of the body’s calcium is stored inside bones and teeth. It is necessary for healthy bones, for maintaining an adequate heartbeat, for maintaining a proper pH balance in the body, and for the process of coagulation (blood clotting). Calcium levels are measured to diagnose blood-clotting disorders and pH imbalance. Also, calcium levels are used to diagnose disorders of the parathyroid glands, which regulate calcium levels in the blood. Pregnant women often have low levels of calcium, as do older people, and often take calcium supplements to prevent bone loss. Otherwise, low calcium levels in the blood could cause calcium ions to move from bones and teeth into the blood, weakening the bones and teeth as blood calcium levels are restored. Calcium levels in the blood cannot be used to determine if patients are getting enough calcium from their diet or if calcium is being lost from the bones (as part of osteoporosis).

Phosphorus exists mostly in bones and teeth (about 80 percent). It generally has an inverse relationship with calcium, such that it decreases as calcium increases and vice versa. Very few conditions will affect phosphorus levels in the blood, so testing for phosphorus alone is not usually very helpful. However, in combination with calcium blood testing, phosphorus testing can be a valuable diagnostic tool.

Sodium is a vital electrolyte in the fluid that carries nutrients to cell tissue and helps regulate blood pressure. Sodium levels can directly influence potassium and chloride levels in the body. Because of this, sodium levels are a good indicator of overall electrolyte balance. Sodium is a component of table salt (sodium chloride) and most people consume far more sodium each day than their bodies need. Over time, too much sodium may lead to an increase in blood pressure, increasing the risk of high blood pressure (hypertension), stroke, kidney failure and heart disease.

Chloride helps regulate blood pressure and volume by balancing its negative charge with the positive charge of sodium. Chloride levels in the blood are used to evaluate the body’s pH balance and fluid levels. Like sodium, most people ingest more chloride through table salt than their bodies require. Heart failure or swelling (edema) can cause low chloride levels (hypochloremia). High levels of chloride (hyperchloremia) may indicate severe dehydration, kidney failure, head injury or other conditions. Chloride levels generally increase as sodium levels increase and vice versa. They react inversely with bicarbonate, increasing as bicarbonate decreases and vice versa.

Potassium maintains pressure in body fluids and regulates pH balance, kidney function and enzyme (complex proteins found in body cells that act as catalysts) activity. Blood potassium levels become high (hyperkalemia) following a heart attack because excess amounts are released into the blood. Over the long term, low potassium levels (hypokalemia) can lead to ventricular fibrillation, respiratory paralysis or cardiac arrest. Low potassium levels may also affect the heart’s electrical activity and can often be seen on an electrocardiogram (EKG). For this reason, potassium levels can be helpful in diagnosing the cause of several forms of arrhythmias (irregular heart rhythms).

Magnesium is important for healthy nerve function and muscle contraction. Magnesium testing is used to evaluate electrolyte imbalance and to assess nerve and muscle functions. Low magnesium levels can cause arrhythmias, muscle weakness or cramps, seizures and other problems. High magnesium levels are usually an indicator of kidney failure.

Bicarbonate is a form of carbon dioxide (CO2) found in the blood and is a byproduct of metabolism. When the amount of CO2 in the red blood cells is too high, the gas spills out of the cells into the plasma (the liquid part of blood). Once in plasma, CO2 may join with water to produce an acid (carbonic acid) or with hydrogen to form bicarbonate. Therefore, bicarbonate levels are an indirect measurement of the amount of CO2 in the bloodstream. High levels of carbon dioxide (CO2) could indicate one of the following:

• A disease that decreases blood pH (respiratory acidosis). These diseases include chronic obstructive pulmonary disease (COPD) and pneumonia.
  
  
• A problem with the body’s ability to use food for energy (metabolic alkalosis), as seen in such diseases as Cushing or Conn syndrome (both adrenal malfunctions) or severe vomiting.
  
  
• Unreliable test results because the person had been using drugs such as corticosteroids, diuretics, barbiturates or high doses of steroid hormones. Test results may also be higher than actual levels if the person had an excessive amount of antacids or black licorice.

Low CO2 levels could indicate one of the following:

• A disease that increases blood pH (respiratory alkalosis). This condition is associated with severe asthma, pneumonia, cirrhosis of the liver, alcoholism, liver failure and severe anxiety.
  
  
• Metabolic problems that decrease blood pH (metabolic acidosis), such as uncontrolled diabetes, kidney or heart failure, aspirin overdose, shock, or ingesting methyl alcohol (anti-freeze or wood alcohol).
  
  
• Unreliable test results because the patient had been using aspirin or certain types of antibiotics.

Many factors may affect electrolyte panel results, including pregnancy and recent surgery or illness. Many electrolyte tests require patients to refrain from eating for six to 12 hours prior to testing. Patients should follow their physician’s restrictions on diet, exercise and medication use prior to the test. Medications can affect blood electrolyte levels and electrolyte testing is often performed for that reason. Patients taking medication may undergo regular electrolyte testing to monitor the doses of their medication and prevent side effects. Medications that may affect blood electrolyte levels include:

Electrolyte tests are measured in milligrams per deciliter (mg/dl) or milliequivalents per liter (mEq/L). It's important to note that normal levels, or reference ranges, may vary slightly from source to source and lab to lab. It's important when undergoing blood testing to refer to the reference ranges from the testing laboratory and pay close attention to the normal ranges provided by the physician. A sample of typical references for an electrolyte panel might include:

• Calcium. Normal levels are 8.5 to 10.9 mg/dl. Levels in children can be as high as 12 mg/dl because their bones are still growing.
  
  
• Phosphorus. Normal levels are 2.4 to 4.1 mg/dl. Levels in children can be as high as 7 mg/dl.
  
  
• Sodium. Normal levels are 136 to 144 mEq/L.
  
  
• Chloride. Normal levels are 101 to 111 mEq/L.
  
  
• Potassium. Normal levels are 3.7 to 5.2 mEq/L.
  
  
• Bicarbonate (and carbon dioxide). Normal levels are 22 to 34 mEq/L.
  
  
• Magnesium. Normal levels are 1.5 to 2.5 mEq/L.

Abnormal electrolyte levels may indicate the following conditions:

• Heart failure. A serious condition in which the heart is not pumping well enough to meet the body’s demand for oxygen.
  
  
• Arrhythmias. Abnormal heart rhythms resulting from an abnormal deviation or malfunction in the heart’s electrical system.
  
  
• Diabetes. A metabolic condition in which blood glucose levels are too high because of either a lack of, or inability to use, insulin.
  
  
• Endocrine disorders. Electrolytes are produced by various glands within the body. Low levels of a specific electrolyte in the blood could be an indication that the gland that produces the electrolyte is not functioning properly.
  
  
• Malnutrition. Inadequate nutrition that may be caused by an unbalanced diet or malabsorption, a condition in which the body has difficulty digesting or absorbing nutrients from food.
  
  
• Severe dehydration. Not enough fluids in the body.
  
  
• Gastrointestinal disease.
  
  
• Bone disease.
  
  
• Lung disease.
  
  
• Kidney disease or failure.
  
  
• Liver disease.
  
  
• Tissue trauma.
  
  
• Hemolysis (dissolving of red blood cells).

Preparing questions in advance can help patients have more meaningful discussions with their physicians. Patients may wish to ask their physicians the following questions related to electrolyte panels:

1. Will the same electrolytes be tested each time I have this test?
   
   
2. Are there other tests that should be performed at the same time I have this test?
   
   
3. If I change medications, will I still have to have my electrolytes monitored?
   
   
4. What do my electrolyte results indicate about my heart condition?
   
   
5. I have diabetes. How does an electrolyte panel differ from my regular glucose testing?
   
   
6. How often do I need to have this test?
   
   
7. What changes can I make to improve my electrolyte levels?
   
   
8. How long before this test must I avoid other medications?
   
   

9. If my electrolyte levels are abnormal, can I take medications to correct them?
   
   

10. Are there any other conditions that may be altering my electrolyte levels?