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What Does an Electrolyte Panel Test?

Cherilyn Cecchini, MDKatie E. Golden, MD
Published on February 8, 2022

Key takeaways:

  • An electrolyte panel is a blood test that measures several different substances in the body. It can provide important information about your hydration and nutrition, kidney function, and overall health. 

  • This test has many uses. Your provider may order an electrolyte panel as part of your regular checkup, to monitor the levels of specific electrolytes, or to help diagnose the cause of new or unexplained symptoms.

  • Your electrolyte levels may change if you’re taking certain medications or have certain medical conditions. This test helps to ensure that your electrolyte levels remain in the normal range since these minerals affect key bodily functions.

Close-up on a doctor or lab tech holding test tubes for an electrolyte panel test.
Shidlovski/iStock via Getty Images

An electrolyte panel is a blood test. It measures the levels of the body’s main electrolytes that play an important role in many bodily functions, such as heart rhythm, muscle contraction, and brain function. It also includes tests to assess kidney function and hydration status. We’ll explain which substances an electrolyte panel measures, common reasons providers order them, and how to read your results.

What does an electrolyte panel measure?

An electrolyte panel (also referred to as a “metabolic panel”) measures electrolytes and other substances in the blood that play important roles in your overall health. These include:

  • Sodium (Na): plays a key role in fluid balance and brain function

  • Potassium (K): regulates the heartbeat as well as nerve and muscle activity

  • Chloride (Cl): contributes to fluid balance and acid-base levels in the blood

  • Carbon dioxide (CO2): indicates how well your body is maintaining the right acid-base balance

  • Blood urea nitrogen (BUN) and creatinine (Cr): two waste products that provide a measure of kidney function

  • Glucose: also known as “blood sugar”

Together, these components make up a basic metabolic panel (BMP). There’s also a more extensive panel that providers can order if needed. 

What’s a comprehensive metabolic panel?

In order to capture a more detailed picture of your health, your provider may order a more extensive electrolyte panel called a “comprehensive metabolic panel” (CMP). A CMP includes all of the components of a basic panel, along with a few more electrolytes and tests to evaluate your liver function.

A CMP includes these additional tests:

  • Total protein: a measurement of nutritional status as well as liver and kidney health

  • Calcium (Ca): a mineral important for bone and muscle health

  • Magnesium (Mg): a mineral that supports nerve and muscle function

  • Phosphate (PO4): another mineral that supports nerve, bone, and muscle health

A CMP also includes several tests that assess liver health and function. These include: 

  • Alanine transaminase (ALT): a liver enzyme that breaks down protein

  • Aspartate transaminase (AST): a liver enzyme that supports metabolism

  • Alkaline phosphatase: an enzyme found in the liver, bones, digestive tract, and kidneys that helps support digestion and bone health

  • Total bilirubin: a byproduct of red blood cell breakdown that the liver processes

  • Albumin: a protein the liver makes 

Who needs an electrolyte panel?

An electrolyte panel can be a useful lab test for many different reasons. Your provider may order one as part of your regular checkup or just to get a general picture of your overall health. Your provider may also order an electrolyte panel to: 

  • Monitor kidney function

  • Monitor liver function

  • Check your hydration or nutrition status if there are concerns about dehydration or malnutrition

  • Check the electrolytes that are important for healthy heart function, like potassium, magnesium, and calcium

  • Check the electrolytes for healthy brain function, like sodium

  • Monitor glucose and electrolytes in someone with diabetes

  • Understand symptoms that are hard to explain, like weakness, fatigue, lack of appetite, or dizziness

  • Help diagnosis a specific medical condition, such as certain endocrine (hormone) conditions, kidney disease, or liver disease

Your provider may also use this test to monitor levels that medications can affect. Common medications that affect electrolyte levels and kidney function include:

What is a normal electrolyte panel?

There’s a general range of acceptable values for each of the electrolytes measured in a panel. Certain labs may use different cut-off values, which is important to note when interpreting your test results. When you look at your results, it will likely include the normal range for that specific lab.

Standard or normal ranges for a BMP are:

  • Na: 134 to 144 mmol/L

  • K: 3.5 to 5.2 mmol/L

  • Cl: 96 to 106 mmol/L

  • CO2: 20 to 29 mmol/L

  • BUN: 9 to 23 mg/dL

  • Cr: 0.57 to 1.00 mg/dL

  • Glucose: 65 to 99 mg/dL

And an example of normal ranges for the values included in a CMP are:

  • Total protein: 6.0 to 8.5 g/dL

  • Albumin: 3.8 to 4.8 g/dL

  • Ca: 8.7 to 10.2 mg/dL

  • Mg: 1.3 to 2.1 mEq/L

  • PO4: 2.8 to 4.5 mg/dL

  • ALT: 0 to 32 IU/L

  • AST: 0 to 40 IU/L

  • Alkaline phosphatase: 39 to 117 IU/L

  • Total bilirubin: 0 to 1.2 mg/dL

It can be confusing and scary to receive lab results that are flagged as abnormal, especially if you haven’t had a chance to talk to your provider. Remember that not all abnormal values are a cause for concern, and it’s common for many of these values to fluctuate from day to day. And some of the abnormalities may not even be accurate. Lab errors happen, and sometimes your provider may recommend repeating a test to make sure that it’s right.

Here’s another thing to keep in mind when interpreting the status of your health: It’s generally more useful to look at lab value trends over time — rather than focusing on one test or data point. It may be tempting to jump to a conclusion about what a high or low number may mean, but it helps to consider the bigger picture. When you discuss the results of your labs with your provider, they can help put them into context and compare them to your past lab results.

The bottom line

Electrolytes are important substances that affect key bodily functions. Your doctor may measure your electrolyte levels during your routine health checkup to ensure that they are all within the normal range. Monitoring these levels may also be important if you have a certain medical condition, or if you’re taking certain medications that affect them. Oftentimes, monitoring the levels over time is more useful than an isolated number. Consult your provider if you’re concerned about a lab level, and they can help you interpret what it means for you and your health.

References

NHS. (2018). Electrolyte test.

Kids Health. (n.d.). Blood test: Comprehensive metabolic panel (CMP).

View All References (2)

Kids Health. (n.d.). Basic blood chemistry tests.

Raebel M. A., et al. (2005). Laboratory monitoring of drugs at initiation of therapy in ambulatory care. Journal of General Internal Medicine.

GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.

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