Bicarbonate is an electrolyte, a negatively charged ion that is used by the body to help maintain the body’s acid-base (pH) balance.
This test is to measure the amount of carbon dioxide in the liquid part of your blood, called the serum. In the body, most of the CO2 is in the form of a substance called bicarbonate (HCO3-). Therefore, the CO2 blood test is really a measure of your blood bicarbonate level.
Normal bicarbonate levels are: 23 to 30 mEq/L in adults.