Electrolyte Panel and Cancer

Electrolyte Panel and Cancer

Reviewed By:
Mark Oren, M.D., FACP
Martin E. Liebling, M.D., FACP


Electrolytes are minerals found naturally in the body that help regulate a number of functions. An electrolyte panel is a group of blood tests that measures electrolyte levels to assess the general functioning of the patient’s organ systems. The results of an electrolyte panel can help the physician make a diagnosis of a disease – including cancer – or help monitor the progress or side effects of treatment.

Electrolyte imbalance in an individual can be caused by  dehydration due to excessive vomiting, diarrhea, sweating and high fever. Cancerpatients who receive certain treatments, such as chemotherapy, are particularly at risk for electrolyte imbalances, due to the likelihood of these side effects.

Symptoms of electrolyte levels that are too high or too low may include weakness, muscle spasms, lethargy  and confusion. The symptoms depend on which electrolyte is out of balance, its level in the body and the cause of the imbalance. Among cancer patients, one of the most serious electrolyte conditions is hypercalcemia (high blood calcium levels). Severe hypercalcemia  can be life-threatening and requires immediate medical treatment.

Patients need to inform their physician of all prescription medications, over-the-counter medications, herbal remedies and vitamin supplements they may be taking prior to testing. A wide variety of substances (e.g., vitamin or mineral supplements) can affect the results of electrolyte panels. Patients also need to follow their physician’s orders carefully regarding the food, drink or medications that should be avoided before the test.

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 metabolic 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. Testing electrolyte levels in the blood can provide physicians with valuable information about chemical imbalances that are present in an individual.

Cancer patients who receive surgery, chemotherapy or radiation therapy are particularly at risk for electrolyte imbalances. These treatments, particularly chemotherapy, often cause vomiting or diarrhea, which can result in an electrolyte imbalance. Diarrhea may affect 50 to 80 percent of chemotherapy patients, according to the  National Cancer Institute (NCI). Diarrhea is also commonly associated with:

  • Radiation therapy to the abdominal and pelvic regions

  • Tumor growth, including:
    • Colon cancer
    • Carcinoid tumors
    • Lymphoma
    • Pancreatic cancer
    • Medullary carcinoma of the thyroid
    • Pheochromocytoma (usually benign tumor of the
      adrenal medulla)

  • Some procedures that may result in side effects causing electrolyte imbalances include:
    • Cholecystectomy. Removal of the gallbladder.

    • Esophagogastrectomy. Removal of a portion of the lower esophagus.

    • Intestinal resection. Removal of intestines.

    • Gastrectomy. Removal of the stomach.

    • Bone marrow transplant

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

  • Calcium. More than 98 percent of the body’s calcium is stored inside bones and teeth. It is necessary for healthy bones, adequate heartbeat, proper pH balance in the body, and the process of coagulation (blood clotting). Calcium levels are measured to diagnose blood-clotting disorders and pH imbalance. They can also reveal disorders of the parathyroid glands, which regulate calcium absorption in the blood. Also, medullary thyroid carcinoma (MTC) is a thyroid cancer that makes calcitonin, a hormone that helps control the amount of calcium in blood.

    Pregnant women often have low levels of calcium, as do older people, and often take calcium supplements to prevent bone loss. The supplements prevent calcium ions from moving from bones and teeth into the blood, weakening the bones and teeth. 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).

    A high level of calcium in the blood (hypercalcemia) may be caused by parathyroid disease, cancer or cancer treatments. The symptoms of hypercalcemia may include nausea, vomiting, abdominal pain and constipation. It also may lead to fatigue, moodiness, confusion and arrhythmias (irregular heartbeat). Hypercalcemia can be difficult to manage in cancer patients and may become severe, requiring immediate medical treatment.

  • Phosphates. 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 affect phosphorus levels in the blood, so testing for phosphorus alone is not usually very helpful. However, in combination with calcium blood testing, phosphous testing can be a valuable diagnostic tool.

  • Sodium. A vital electrolyte in the fluids 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 (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 (acid-alkaline) balance and fluid levels. Like sodium, most people ingest more chloride through table salt than their bodies require. Heart failure or water retention (edema) can cause low chloride levels (hypochloremia). High levels of chloride (hyperchloremia) may indicate severe dehydration, kidney shutdown, head injury or other conditions.

  • 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. High levels of potassium, uric acid and phosphorus along with low calcium levels may indicated tumor lysis syndrome (TLS), a condition found among cancer patients treated with chemotherapy. Symptoms of TLS can include nausea and vomiting, joint pain, shortness of breath and lethargy. If TLS is left untreated, it can progress to severe problems and life-threatening complications.

  • Magnesium. 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. 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’s disease 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 other steroid hormones. Test results may also be higher than actual levels if the person ate 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 (antifreeze or wood alcohol).

    • Unreliable test results because the patient had been using aspirin or certain types of antibiotics.

The values of test results may vary from laboratory to laboratory. However, normal ranges may be as follows:.

ElectrolyteNormal Adult Range
Calcium4.5 to 5.5 mEq/L*
Chloride97 to 107 mEq/L
Magnesium1.5 to 2.5 mEq/L
Potassium3.5 to 5.3 mEq/L
Sodium136 to 145 mEq/L

* milliequivalents per liter

Factors that may affect panel results

Many factors may affect electrolyte panel results, including pregnancy, 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:

  • Antibiotics. Medications that harm or kill microorganisms and are commonly used to treat bacterial infections.
  • Diuretics. Medications that promote the formation of urine in the kidneys, causing the body to flush out fluids and minerals through the urine.
  • Oral contraceptives. Medications that regulate the reproductive cycle of women and prevent pregnancy.
  • Antidiabetics. Medications that stimulate the production of insulin for treatment of patients with adult onset diabetes. Insulin injections needed by diabetic patients whose bodies are no longer able to produce insulin can also affect electrolyte levels.
  • Anabolic steroids. A synthetic hormone used to stimulate metabolism and muscle growth.
  • Corticosteroids. A synthetic hormone used as an antiinflammatory agent.
  • Anticonvulsives. Medications to treat convulsions and seizures.
  • 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.
  • Antidepressants (long-term use). Medications used to treat clinical depression, which is sometimes a symptom of cancer or cancer treatments.
  • Aspirin overdose. A nonsteroidal anti-inflammatory drug (NSAID) that is typically used as a pain-reliever (analgesic) but also reduces inflammation and inhibits the formation of blood clots (anticoagulant).
  • Other NSAIDs. Medications that reduce pain and inflammation by inhibiting the production of certain chemicals in the body. Many cancer patients use NSAIDs for relief of minor pain.
  • 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 typically performed in a physician’s office for laboratory analysis or directly at the lab. Cancer patients may have the test done at their oncologist’s office during check-ups or at the time of chemotherapy treatments.

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 firm pressure over the puncture site. After several minutes, the cotton will be discarded or replaced, and a small bandage will be placed on the puncture wound. The entire process takes less than 10 minutes. The blood drawn is placed in tubes and the sample is sent to a laboratory for analysis.

In emergency situations, the blood sample is processed and analyzed immediately, with results ready in minutes.

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, exercise and taking medications according to their physician’s orders.

Questions for your doctor on electrolyte panel

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor or healtcare professional the following questions about an electrolyte panel:

  1. What do you hope to find by doing an electrolyte panel?
  2. Will I need to make any special preparations, such as fasting, before the test?
  3. Am I taking any medications that may affect the results?
  4. Where can I have the test done?
  5. When and from whom will I receive my test results?
  6. What do my test results indicate?
  7. Are the imbalances due to my cancer or cancer treatments?
  8. What type of problems can this imbalance cause?
  9. How serious is this condition?
  10. How can I improve my electrolyte levels?
  11. How can I prevent electrolyte problems during treatment?
  12. How often will I need to have an electrolyte panel?
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