CO2: About This Test

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What is it?

This test measures the level of bicarbonate in your blood. Bicarbonate is a form of carbon dioxide (CO2). CO2 is a waste product of metabolism. Your blood carries it to your lungs, where it is exhaled. Bicarbonate keeps your blood at the right pH level (not too acidic, and not too basic).

The test is also called a carbon dioxide test or a bicarbonate test.

Why is this test done?

CO2 testing may be done as part of a group of blood tests (chemistry screen) to help find the cause of many kinds of symptoms, including many kidney diseases, some lung diseases, and metabolic conditions.

How can you prepare for the test?

  • In general, you don't need to prepare before having this test. Your doctor may give you some specific instructions.

What happens during the test?

  • A health professional takes a sample of your blood.

What else should you know about the test?

  • Your results will include an explanation of what a "normal" result is. This is called a "reference range." It is just a guide. Your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed may still be normal for you.

How long does the test take?

  • The test will take a few minutes.

What happens after the test?

  • You will probably be able to go home right away.
  • You can go back to your usual activities right away.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse call line if you are having problems. It's also a good idea to keep a list of the medicines you take. Ask your doctor when you can expect to have your test results.

Where can you learn more?

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Current as of: October 9, 2017