Carbon Dioxide (CO2) in Blood
Reviewed
A carbon dioxide (CO2) blood test measures the amount of carbon dioxide in your blood, mostly in the form of bicarbonate. It is often part of an electrolyte panel and can help diagnose or monitor conditions related to an electrolyte imbalance, such as kidney, lung, or liver diseases.
Preparation and collection
Tell your provider about all medicines you take. You may need to stop certain medicines before the test. If your provider has ordered more tests on your blood sample, you may need to fast for several hours before the test. Follow your provider's instructions.
Understanding this test
Use the reference interval and units printed by the laboratory that performed the test. A result outside that interval is not a diagnosis by itself, and a result inside it does not rule out every condition. Your symptoms, history, medicines, timing, and related tests can change what the result means.
- Results may be affected by certain prescription and over-the-counter medicines.
- An abnormal result does not necessarily mean you have a condition that needs treatment; your provider will order other tests to confirm a diagnosis.
What to do next
Your healthcare provider will interpret your CO2 blood test results, considering your symptoms, medical history, and other test results. Reference ranges may vary by laboratory. Do not self-diagnose.
Evidence source
U.S. National Library of Medicine: Carbon Dioxide (CO2) in Blood