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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 can you prepare for the test?

In general, you don't need to prepare before your child has this test. The doctor may give you some specific instructions.

What happens during the test?

A health professional takes a sample of your child's blood.

How long does the test take?

The test will take a few minutes.

Follow-up care is a key part of your child's treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse call line if your child is having problems. Ask your doctor when you can expect to have your child's test results.

Where can you learn more?

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