An electrolyte panel is a group of blood tests that measure levels of electrolytes to assess the functioning of a patient’s organ systems. Electrolytes are minerals that are found naturally in the body and help regulate many functions.
Electrolytes that are often measured include calcium, potassium, chloride and sodium, although there are many others. The results of an electrolyte panel can help a physician make a diagnosis or monitor the progress of treatment with medications.
Abnormal electrolyte levels may be caused by several conditions, including diabetes, other endocrine conditions and diabetic complications, including:
- Diabetic nephropathy. Kidney disease or damage caused by diabetes.
- Diabetic ketoacidosis. A serious condition that can occur when a severe lack of insulin causes the body to break down fats instead of glucose (blood sugar) for energy.
- Hyperosmolar hyperglycemic nonketotic syndrome. A serious condition that includes high glucose (hyperglycemia) and dehydration.
Hyperthyroidism. Overactive thyroid gland, which can deprive the bones and other tissues of calcium.
Parathyroid disorders. Conditions that can impair bones, nerves and muscles by affecting levels of calcium and phosporus.
Patients need to inform their physician of all prescription medications, over-the-counter medications, herbal remedies and vitamin supplements that they may be taking because a wide variety of substances, including insulinand antidiabetic agents, can affect test results. They also need to follow their physician’s orders regarding foods, beverages or medications that can be taken (or should be avoided) before the test.
Electrolytes are minerals found throughout the body in varying concentrations. They move between locations to restore balance (homeostasis) when needed. Electrolytes include calcium, potassium, chloride and sodium, in addition to many others. Carbon dioxide, a waste product, is also frequently measured during an electrolyte panel.
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 (pH), nerve conduction, blood clotting and muscle contraction.
Electrolyte imbalance can be caused by a number of conditions, among them diabetes and complications associated with the disease. It can result from problems such as dehydration, fever and vomiting. Endocrine disorders, kidney failure, heart disease and digestive disorders can lead to long-term electrolyte imbalances.
About electrolyte panels
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, minerals that carry an electrical charge, 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. Testing electrolyte levels in the blood can provide physicians with valuable information about what chemical imbalances are occurring in the body.
An electrolyte panel typically includes blood levels of the following:
- Calcium. More than 98 percent of the body’s calcium is stored inside bones and teeth. Calcium is necessary for:
- Bone health
- Maintaining an adequate heartbeat
- Maintaining a proper pH balance in the body
- Coagulation (blood clotting)
- Phosphates. About 80 percent of phosphorus exists in bones and teeth. It generally has an inverse relationship with calcium, meaning it decreases as calcium increases and vice versa. Very few conditions affect levels of phosphorus in the blood, so testing for phosphorus alone is not usually helpful. However, in combination with calcium blood testing, phosphorus testing can be a valuable diagnostic tool.
- Sodium. Sodium is a vital electrolyte in the fluids that carry nutrients to cells and help 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, chronic kidney failure, stroke and heart disease.
- Chloride. Chloride helps to 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. As with sodium, most people ingest more chloride through table salt than their bodies require. Heart failure and water retention (edema) can cause low chloride levels (hypochloremia). High levels of chloride (hyperchloremia) may indicate severe dehydration, kidney dysfunction 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. Potassium regulates many of the body’s organ functions and basic physiology. Blood potassium levels become high (hyperkalemia) after muscle damage because excess amounts are released into the blood, or from kidney failure or acidosis. Low potassium levels (hypokalemia) can lead to respiratory paralysis, ventricular fibrillation (a life-threatening type of irregular heartbeat) 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. 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. A low level of magnesium (hypomagnesemia) can cause heart arrhythmias, muscle weakness or cramps, seizures and other problems. A high level of magnesium (hypermagnesemia) is usually an indicator of kidney failure.
- Bicarbonate. Bicarbonate, a form of carbon dioxide (CO2) found in the blood, 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 carbonic acid (bicarbonate). The level of bicarbonate is thus an indirect measurement of the amount of CO2 in the bloodstream. High levels of 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 disease that increases blood pH (metabolic alkalosis), such as Cushing syndrome or Conn syndrome (both adrenal gland 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 ate an excessive amount of antacids or black licorice.
- A disease that decreases blood pH (respiratory acidosis). These diseases include chronic obstructive pulmonary disease (COPD) and pneumonia.
Low CO2 levels could indicate one of the following:
- Metabolic problems that decrease blood pH (metabolic acidosis), such as uncontrolled diabetes, kidney or heart failure, aspirin overdose, shock or ingesting methyl alcohol (antifreeze or wood alcohol).
- A disease that increases blood pH (respiratory alkalosis). This condition is associated with asthma, pneumonia, liver disease and severe anxiety.
- Unreliable test results because the patient had been using aspirin or certain types of antibiotics.
Factors that may affect panel test results
Many factors may affect results of electrolyte panel. Many electrolyte tests require patients to refrain from eating for six to 12 hours before 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 to monitor the doses of medication and prevent side effects. Medications that may affect blood electrolyte levels include:
- Antidiabetic agents. Medications used to treat type 2 diabetes by decreasing the amount of glucose (blood sugar) circulating in the blood.
- Insulin. A glucose-regulating hormone. All people with type 1 diabetes and some people with other forms of diabetes take insulin by injection, pump or other means.
- Diuretics. Medications that promote the formation of urine in the kidneys, causing the body to flush out fluids and minerals through the urine.
- Antibiotics. Medications that harm or kill bacteria and are commonly used to treat bacterial infections, including urinary tract infections and some skin disorders.
- Oral contraceptives. Medications that regulate the reproductive cycle of women and prevent pregnancy.
- Anabolic steroids. Synthetic hormones used to stimulate metabolism and muscle growth.
- Corticosteroids. Synthetic hormones used as anti-inflammatory and immunosuppresive agents.
- Anticonvulsives. Medications to treat convulsions, seizures and other conditions, including painful diabetic neuropathy.
- Androgens. Male hormones naturally found in the body that are used in the treatment of some breast cancers in females and late puberty or other conditions in males.
- Estrogen. Female hormone naturally found in the body. A synthetic form of this hormone is used as part of hormone replacement therapy after menopause, and anti-androgens can be used in men to treat prostate cancer.
- Antidepressants (long-term use). Medications used to treat clinical depression and, in some cases, pain including diabetic neuropathy.
- Nonsteroidal anti-inflammatory drugs (NSAIDs). Medications that reduce pain and inflammation by inhibiting the production of certain chemicals in the body. Aspirin is a common NSAID used to relieve pain, reduce inflammation and inhibit the formation of blood clots (anticoagulant).
- Vitamin D supplements (long-term use).
- Antacids containing calcium.
- Antiseptic acids. Substances, usually applied to the skin, that inhibit the growth of microorganisms such as bacteria.
- Glaucoma medications.
- Cough medicines.
- Calcium salts.
- Laxatives (long-term use).
Before, during and after the test
Patients should follow their physician’s restrictions on diet, exercise and medication use prior to the test. The test is performed in a physician’s office for laboratory analysis or directly at the lab. Blood is usually drawn from a vein (venipuncture) from the inside of the elbow or the back of the hand. First the puncture site is sterilized with antiseptic and an elastic band is wrapped around the patient’s upper arm. As a result, the pressure restricts blood flow through the vein and causes the veins below the band to fill with blood.
A needle is then inserted into a vein. Occasionally more than one puncture is necessary to locate a vein. Some people may feel a moderate level of pain when the needle is inserted, but most only feel a prick or stinging sensation. Once the needle is inserted into a vein, a tube is attached to collect the blood as it begins to flow out. The elastic band is then removed.
After the necessary amount of blood is collected, the needle is withdrawn and a small cotton ball or pad is applied with light pressure over the puncture site. After several minutes, the cotton will be discarded or replaced, and a small bandage may be placed on the puncture wound. The entire process takes less than 10 minutes. The sample is sent to a laboratory for analysis, and results are returned in several days.
Despite the precautions taken to avoid bruising and soreness, it does sometimes occur. Typically, this is not a cause for great concern. To minimize soreness, patients may immediately apply a warm compress to the puncture site and repeat the application every three hours until the discoloration or pain subsides.
After their blood is drawn, patients may resume eating, exercising and taking medications according to their physician’s orders.
Understanding electrolyte panel results
Electrolyte tests are measured in milligrams per deciliter (mg/dL) or milliequivalents per liter (mEq/L). Normal blood levels are as follows:
- Calcium: 8.5 to 10.5 mg/dL. Levels in children can be as high as 12 mg/dL because their bones are still growing.
- Phosphorus: 2.4 to 4.1 mg/dL. Levels in children can be as high as 7 mg/dL.
- Sodium: 136 to 144 mEq/L
- Chloride: 101 to 111 mEq/L
- Potassium: 3.7 to 5.2 mEq/L
- Bicarbonate (and carbon dioxide): 22 to 34 mEq/L
- Magnesium: 1.5 to 2.5 mEq/L
Abnormal electrolyte levels may indicate or result in the following conditions:
- Diabetes. A condition in which glucose (blood sugar) levels are too high because of either a lack of, or inability to properly use, insulin.
- Other endocrine disorders, including hyperthyroidism, parathyroid disease and some adrenal conditions. Electrolytes are controlled by various glands within the body. Improper levels of a specific electrolyte in the blood could be an indication that the gland that regulates the electrolyte is not functioning properly.
- Severe dehydration. Not enough fluids in the body. Diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic nonketotic syndrome (HHNS) are two diabetic conditions that are strongly linked to dehydration. Common causes of dehyration include diarrhea, vomiting and insufficient intake of fluids.
- Kidney diseases, including diabetic nephropathy and kidney failure.
- Gastrointestinal disease, including gastroparesis (delayed emptying of the stomach), which is a form of autonomic neuropathy.
- Heart attack (myocardial infarction). An event that results in permanent heart damage or death.
- 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.
- Malnutrition. Inadequate nutrition that may be caused by an unbalanced diet, an eating disorder or malabsorption, a condition in which the body has difficulty digesting or absorbing nutrients from food.
- Bone, liver or lung disease.
- Tissue trauma.
- Hemolysis (dissolving of red blood cells).
Frequency of electrolyte testing
Not only is electrolyte testing performed as part of a basic evaluation and diagnosis, but it may also be used to monitor the progress of treatment because many medications will affect electrolyte balances within the body. For this purpose, regular testing may be required for some conditions.
There are various situations in which a person with diabetes would require an electrolyte panel. Those with diabetic nephropathy may require electrolyte panels to monitor the progression of the disease. In addition, patients suffering from diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic nonketotic syndrome (HHNS) may have their electrolyte levels measured to confirm and determine the severity of dehydration.
People with other endocrine disorders, including hyperthyroidism and parathyroid disease, may also be monitored with electrolyte tests.
Questions for your doctor
Preparing questions in advance can help patients have more meaningful discussions with their physicians. Patients may wish to ask their physicians the following questions about electrolyte panels:
- Why is an electrolyte panel recommended for me?
- What will my test measure?
- How often to I need to have this test?
- Will the same electrolytes be tested each time I have this test?
- Are there other tests that should be performed at the same time I have an electrolyte panel?
- Do I need to withhold medication or do anything else to prepare for this blood test?
- When will my test results be ready, and who will explain them to me?
- What do my electrolyte results indicate about my diabetes, thyroid, parathyroid glands, adrenal glands, kidneys, heart or other concerns?
- Do my results show a need to begin a treatment or change my treatment plan?
- If I change medications, will I still have to have my electrolytes monitored?
- Can I make any changes to improve my electrolyte levels?