Addison's disease, lactic acidosis, kidney disease, diarrhea and ethylene glycol poisoning are causes of low CO2 blood levels, according to MedlinePlus. Seizures, cancer, diabetic ketoacidosis and hyperventilation are also causes, claims Healthline.
The normal range of CO2 levels is 23 to 29 milliequivalent units per liter of blood. A low CO2 level with a low pH balance is known as metabolic acidosis, while a low level with a high pH is known as respiratory alkalosis, says Healthline.
Functions of the kidneys and the lungs affect CO2 blood test levels, claims MedlinePlus. Other causes of low CO2 blood levels include dehydration, severe malnutrition, alcohol overdose and aspirin consumption, according to WebMD.