What Does an Electrolyte Panel Test?

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 

EXPERT PICKS: WHAT TO READ NEXT

• Do you need an electrolyte boost? When should you reach for an electrolyte drink — and when is drinking water enough to stay hydrated?

• What does that lab test mean? It’s normal to feel anxious when you get the results of a blood test. We walk you through the most common lab tests, and what’s considered normal. 

• How do blood tests measure heart health? These blood tests check for immediate heart problems and provide information about your risk of developing heart disease.

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

Read more like this

Explore these related articles, suggested for readers like you.

Is Lemon Water Good for You? A Dietitian Separates Fact From Fiction

What Are Acidic Foods, and Do You Really Need to Avoid Them?

Having Muscle Cramps? These Foods May Help Keep Them at Bay

Suflave: Uses, Side Effects, Dosage, & More

View more

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

• Diuretics (like furosemide, bumetanide, hydrochlorothiazide, and chlorthalidone), which can help to control blood pressure

• Medications that treat heart rhythm problems, like amiodarone, digoxin, and procainamide

• Blood pressure medications, like angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs)

• Anti-seizure medications, such as primidone (Mysoline) and valproic acid

• Antifungal medications, like Lamisil (terbinafine) 

• Cancer or rheumatoid arthritis treatments, such as methotrexate 

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.

Why trust our experts?

Written by:

Cherilyn Davis, MD

Cherilyn Davis, MD, is a board-certified pediatrician in NYC. She's held local and national roles at the American Medical Women's Association, including board member of the physician division and physician chair of social media.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

Our editorial standards

Meet our experts