CO2: About Your Child's Test

What is it?

This test measures the level of bicarbonate in your child's blood. Bicarbonate is a form of carbon dioxide (CO2). CO2 is a waste product of metabolism. The blood carries it to the lungs, where it is exhaled. Bicarbonate keeps your child's 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 is often done as part of a group of blood tests (chemistry screen). It's done to help find the cause of many kinds of symptoms. Some of these symptoms are vomiting, diarrhea, and dehydration. The causes include many kidney diseases, some lung diseases, and metabolic conditions like diabetes.

How do you prepare for the test?

In general, there's nothing you have to do before this test, unless your doctor tells you to.

How is the test done?

A health professional uses a needle to take a blood sample, usually from the arm.

How long does the test take?

The test will take a few minutes.