Electrolytes

Does this test have other names?

Electrolyte panel, Lytes, sodium (Na), potassium (K), chloride (Cl), carbon dioxide (CO2)

What is this test?

This test measures the main electrolytes in your body: sodium, chloride, potassium, and carbon dioxide.

The cells in your body carefully balance fluids and electrolytes, which are electrically charged minerals. Electrolytes move fluid in and out of your cells. They carry nutrients into the cells and waste products back out. Electrolytes also help keep your water level normal and your pH level stable. In other words, they help the acids and bases in your blood stay in balance.

Electrolytes in blood and tissues are in the form of salts. You get electrolytes from the food you eat and fluids you drink.

Why do I need this test?

You may need this test if you feel confused, nauseated, and weak. These are often signs that your body's electrolytes may be out of balance.

If you are in the hospital, your healthcare provider may order an electrolyte panel to help make a diagnosis or rule out other problems. You may also need this test if your healthcare provider wants to monitor your treatment for another condition. For example, heart failure can cause an electrolyte imbalance, so patients in the hospital for heart failure may have this test to see whether treatment is working.

You may also have this test if you have:

• Diarrhea

• Vomiting

• Diabetes

• Heart disease

• Nerve damage

• Muscle problems

• Cancer treatment

• Chronic kidney disease

You may also have your electrolytes tested if you're taking diuretics or other medicines that cause you to have increased urination.

Your healthcare provider may also order this test if you collapse while playing sports or exercising, or if you are hospitalized for a heat-related illness. Because you lose electrolytes as you sweat, dehydration can sometimes lead to a dangerous electrolyte imbalance.

What other tests might I have along with this test?

Your healthcare provider may also order a urine test for chloride, a blood test for glucose, or a basic urinalysis. If you've had a heart attack, you may also get an electrocardiogram, or EKG, along with an electrolyte test. Your healthcare provider may also order other blood tests to see how well your kidneys are working.

What do my test results mean?

Test results may vary depending on your age, gender, health history, the method used for the test, and other things. Your test results may not mean you have a problem. Ask your healthcare provider what your test results mean for you. 

Each part of an electrolyte panel checks for a different dissolved salt, or electrolyte. Results differ depending on your age and health.

Results are given in milliequivalents per liter (mEq/L). Here are the normal ranges for each type of electrolyte in blood:

Potassium (K)

• Adults: 3.5 to 5 mEq/L

• Children: 3.4 to 4.7 mEq/L

• Infants: 4.1 to 5.3 mEq/L

• Newborns: 3.9 to 5.9 mEq/L

If your potassium levels are too high or too low, you may be in danger of shock or a potentially life-threatening heart rhythm.

Chloride (Cl)

• Adults: 98 to 106 mEq/L

• Children: 90 to 110 mEq/L

• Newborn: 96 to 106 mEq/L

• Premature infant: 95 to 110 mEq/L

Sodium (Na)

• Adults: 136 to 145 mEq/L

• Adults over age 90: 132 to 146 mEq/L

• Children: 138 to 146 mEq/L

• Premature infants at 48 hours: 128 to 148 mEq/L 

• Newborns: 133 to 146 mEq/L

Carbon dioxide or bicarbonate (CO2)

• Adults: 23 to 30 mEq/L

• Children: 20 to 28 mEq/L

• Infants: 20 to 28 mEq/L

• Newborns: 13 to 22 mEq/L

How is this test done?

Your electrolytes can be checked with either a blood or urine test. The blood test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand. For a urine test, you provide a urine sample in a specimen container.

Does this test pose any risks?

Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore. 

A urine test poses no known risks.

What might affect my test results?

The amount of fluid you drink or lose can affect your test results. Results can also be affected by vomiting, having diarrhea, or sweating a lot from exercise.

Some medicines, such as those used to lower high blood pressure or reduce stomach acid, can cause electrolyte problems.

How do I get ready for this test?

Ask your healthcare provider whether you need to stop eating certain foods or taking certain medicines before this test. Be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use.