What is an electrolyte panel (electrolyte blood test)?
An electrolyte panel is a blood test that measures the levels of seven electrolytes in your blood. Certain conditions, including dehydration, cardiovascular disease and kidney disease, can cause electrolyte levels to become too high or low. This is an electrolyte imbalance.
Other names for an electrolyte panel test include:
- Electrolyte blood test.
- Electrolyte lab test.
- Serum electrolyte test.
What are electrolytes?
Electrolytes are minerals found in blood, tissue, urine and other body fluids. You also get electrolytes from foods, drinks and supplements. Electrolytes get their name because they give off an electrical charge when they dissolve in body fluids.
Electrolytes play a critical role in:
- Balancing fluids in your body.
- Controlling your heart rate and rhythm.
- Promoting bone and dental health.
- Supporting nerve and muscle function.
- Stabilizing blood pressure.
What is the purpose of an electrolyte panel?
You may get an electrolyte panel as part of a routine physical examination, during hospitalization or to determine the cause of certain symptoms.
An electrolyte panel can detect electrolyte imbalances caused by:
- Dehydration due to not drinking enough liquids or from excessive vomiting, diarrhea, sweating (hyperhidrosis) or fever.
- Cardiovascular disease, heart failure or high blood pressure.
- Kidney disease.
- Liver disease like cirrhosis.
- Overhydration or water intoxication (drinking too much water).
- Substance use disorder.
What is included in an electrolyte panel?
Some tests measure only one specific type of electrolyte. Your provider may order this test to confirm or rule out a suspected condition.
An electrolyte panel checks the levels of multiple minerals in your blood, including:
- Sodium: Controls fluid levels and aids nerve and muscle function.
- Potassium: Supports heart, nerve and muscle function, as well as metabolism.
- Calcium: Supports your musculoskeletal system (bones and muscles), nervous system and circulatory system.
- Chloride: Helps maintain healthy blood pressure and body fluid levels.
- Magnesium: Aids nerve and muscle function and promotes the growth of bones and teeth (skeletal system).
- Phosphate: Develops healthy teeth and bones and aids nerve and muscle function.
- Bicarbonate: Maintains a healthy balance of acids and basic alkaline compounds in blood (acid-base balance). It also moves carbon dioxide through your bloodstream.
Do you need to fast for an electrolyte panel (electrolyte blood test)?
Typically, you don’t have to fast (not eat or drink anything except water) before getting an electrolyte blood test. But your healthcare provider may ask you to fast if the lab will be measuring other substances in your blood sample like cholesterol or blood sugar.
What happens during an electrolyte blood test?
An electrolyte panel is a relatively simple blood draw. The test may take place in a healthcare provider’s office, blood testing lab or hospital. A phlebotomist (a specialist trained in drawing blood) or another provider will take the blood sample.
How should I prepare for an electrolyte blood test?
These steps can help a blood draw go smoothly:
- Stay hydrated: Drink plenty of fluids before the test to help blood flow easier through blood vessels.
- Avoid nicotine: Don’t smoke (including vaping) before a blood draw. Nicotine constricts blood vessels, making it more difficult to insert the needle into a vein.
- Speak up: Let your provider know if you have a fear of needles (trypanophobia) or a fear of blood (hemophobia). There are steps they can take to make the blood draw easier for you.
What should I expect after an electrolyte blood test?
You should wear the bandage for two to four hours to prevent infection. There may be slight inflammation (swelling) or bruising at the needle site, which will go away in a few days.
You can take these steps to minimize bruising or discomfort:
- Place a wrapped ice pack on the bandaged area.
- Take an over-the-counter pain reliever, if needed.
- Avoid lifting heavy items or exercising vigorously for 24 hours after the blood draw.
What are the risks of an electrolyte blood test?
A blood test carries little risk. You may experience a drop in blood pressure during a blood draw. Low blood pressure (hypotension) can make you dizzy or nauseous. Tell your provider if you feel unwell or like you might faint. Your provider can take steps, like reclining you backward, to prevent or alleviate these problems.
Results and Follow-Up
When will I get the test results from an electrolyte panel?
It may take several days for results to come back from a lab. Your healthcare provider will go over the results with you.
What are the normal ranges for electrolytes?
Your age, sex and preexisting health conditions can affect test results. And laboratories often use different methods for measuring electrolytes. This means results can vary from lab to lab.
Labs measure electrolytes by looking at the concentration of the substance in a specific amount of blood. In general, these are the normal ranges for electrolytes:
- Sodium: 136 to 144 mmol/L.
- Potassium: 3.7 to 5.1 mmol/L.
- Calcium: In adults, 8.5 to 10.2 mg/dL.
- Chloride: 97 to 105 mmol/L.
- Magnesium: 1.7 to 2.2 mg/dL.
- Phosphate: 2.5 to 4.8 mg/dL.
- Bicarbonate: 22 to 30 mmol/L.
What happens if the electrolyte panel shows an electrolyte imbalance?
An electrolyte reading above or below the normal range doesn’t necessarily mean that you have a problem that needs treatment. Depending on your symptoms or preexisting health condition, your provider may order additional tests.
These tests may include:
- Anion gap test, which uses results from the electrolyte panel to measure the difference (or gap) between electrolytes that have a positive charge and those that carry a negative charge. A gap that is too high or low (negative) may indicate a problem with your lungs, kidneys or other organs.
- Blood gas test, which measures oxygen, carbon dioxide and acidity in your blood. It can help pinpoint the cause of an acid-base imbalance, such as a lung or kidney problem. The test requires a blood draw.
What should I ask my healthcare provider?
You may want to ask your provider:
- Why do I need this test?
- Do I need to fast, stop smoking or not take medicines before I get the test?
- When will I get the test results?
- Should I be concerned about the test results?
- Will I need additional tests?
- How often do I need an electrolyte blood test?
Frequently Asked Questions
What’s the difference between electrolyte panels and metabolic panels?
Differences between an electrolyte panel and metabolic panel include:
- An electrolyte panel only checks electrolyte levels.
- A basic metabolic panel (BMP) measures the levels of certain electrolytes, along with creatinine, blood glucose and blood urea nitrogen (BUN).
- A comprehensive metabolic panel (CMP) is an expanded BMP test that also measures total protein in your blood, as well as liver enzymes.
Are there at-home electrolyte blood test kits?
No. Only trained medical professionals can do a blood draw for an electrolyte blood test.
A note from Cleveland Clinic
An electrolyte panel provides important information about body fluids, including your blood’s acid-base balance. Your healthcare provider may order an electrolyte blood test to diagnose or rule out a condition if you experience symptoms. You may also get an electrolyte panel if you have a condition that causes an electrolyte imbalance. Results from an electrolyte panel help your doctor decide if treatments are working or whether a disease is getting worse.
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