Carbon Dioxide (Bicarbonate)

Carbon dioxide (CO2) is a gaseous waste product from Reference metabolism Opens New Window. The blood carries carbon dioxide to your lungs, where it is exhaled. More than 90% of carbon dioxide in your blood exists in the form of bicarbonate (HCO3). The rest of the carbon dioxide is either dissolved carbon dioxide gas (CO2) or carbonic acid (H2CO3). Your kidneys and lungs balance the levels of carbon dioxide, bicarbonate, and carbonic acid in the blood.

This test measures the level of bicarbonate in a sample of blood from a vein. Bicarbonate is a chemical (buffer) that keeps the Reference pH Opens New Window of blood from becoming too acidic or too basic.

Bicarbonate is not usually tested by itself. It may be done on a blood sample taken from a vein as part of a panel of tests that looks at other Reference electrolytes Opens New Window, such as sodium, potassium, and chloride. It can also be done as part of an Reference arterial blood gas (ABG) Opens New Window test. For the arterial blood gas study, the blood sample is taken from an artery.

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