Also Known as: carbon dioxide content, CO2 content, carbon dioxide blood test, bicarbonate blood test, bicarbonate test, total CO2; TCO2; carbon dioxide content; CO2 content; bicarb; HCO3
What is a carbon dioxide (CO2) test?
Carbon dioxide (CO2) is a colorless and odorless gas. It is a waste substance that your body produces. Carbon dioxide is carried to your lungs via your blood. Every day, you exhale carbon dioxide and inhale oxygen throughout the day as part of the breathing process. The amount of carbon dioxide in your blood is measured by a CO2 blood test. Carbon dioxide levels in the blood that are too high or too low may indicate a health problem.
What is the test used for?
A CO2 blood test is often ordered as part of an electrolyte panel, a collection of tests often ordered as part of a regular checkup. Electrolytes help to keep your body's acid and base levels in check. Bicarbonate, a type of electrolyte, contains most of the carbon dioxide in your body. The test can also be used to monitor or diagnose electrolyte-related disorders such as kidney diseases, lung disorders, and high blood pressure.
Why and when do you need this test?
If you experience signs of an electrolyte imbalance, your healthcare provider may order a CO2 blood test as part of your regular checkup. These are some of the symptoms:
- Breathing difficulties
- Prolonged Vomiting or diarrhea
What kind of sample is required for the test?
A healthcare provider will use a small needle to obtain a blood sample from a vein in your arm. A small amount of blood will be collected into a test tube or vial once the needle is inserted. When the needle goes in or out, it may sting a little. It usually takes less than five minutes to complete this process.
Do you need to prepare for the test?
A CO2 blood test does not require any specific preparation. You may need to fast (not eat or drink) for several hours before the test as directed by your healthcare provider if he has ordered other blood tests along with it. If there are any special instructions to follow, your health care provider will inform you.
Are there any risks to this test?
Having a blood test carries relatively little risk. You may experience minor pain or bruising where the needle was inserted, but most symptoms disappear quickly.
What do the test results mean?
Abnormal results could indicate an electrolyte imbalance in your body or difficulty with carbon dioxide removal through your lungs. A high level of CO2 in the blood may indicate several conditions including:
- Certain diseases of the lungs
- Cushing's syndrome: an adrenal gland condition in which these glands produce too much of a hormone called cortisol, producing symptoms like muscle weakness, vision problems, and elevated blood pressure.
- Hormonal disorders
- Kidney diseases
- Alkalosis ( a condition in which your blood contains too much base content)
A low level of CO2 in the blood may indicate:
- Addison's disease: another disorder of the adrenal glands in which these glands produce less amount of hormone called cortisol as a result of which several symptoms might occur, including weakness, disorientation, weight loss, and dehydration.
- Acidosis ( a condition in which your blood contains too much acid content)
- Ketoacidosis ( a complication of type 1 and type 2 diabetes)
- Kidney problems
If your test results aren't within the normal range, it doesn't necessarily mean you have a medical problem that needs to be addressed. The quantity of CO2 in your blood can be affected by various things, including certain medications.
Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on June 05, 2023.
Carbon Dioxide (CO2) in Blood: MedlinePlus Medical Test
CO2 Blood Test: Purpose, Procedure, Levels & Results
Frequently ordered together
See Physicians Online
- Thyroid Disorder
- Hormonal Imbalance
Syed Hassan, MD
- General and Urgent Care- all ages
Yanelquis Torres, MD
- Sleep Apnea
- Sleep Disorders
- Jet Lag Disorder
- Shift Work Sleep Disorder
- Restless Leg Syndrome
Ayesha Aslam Mughal, MD
- Acute And Chronic Conditions
Fabiola Baptiste, NP
- High Blood Pressure
- High Cholesterol
Raga Mohamed Ali Osman