The normal range of carbon dioxide levels in the blood is 23 to 29 milliequivalents per liter, according to MedlinePlus. Sometimes other units might be used, in which case the normal range is 23 to 30 millimoles per liter, reports WebMD.
Since CO2 is usually transported in the bloodstream in the form of bicarbonate, a CO2 blood test actually measures bicarbonate levels, explains WebMD. Usually, blood is drawn from a vein near the elbow or hand. Each medical laboratory uses different equipment, so the actual range that is considered normal may differ. Normal results are a sign of healthy kidney, liver and lung functions. Abnormal results could be an indication of many different respiratory or metabolic health issues.