What are the other names for this test?

Total CO2, Carbon dioxide content, CO2 content, Carbon dioxide blood test, TCO2, Bicarbonate blood test, bicarbonate test, HCO3, bicarb

What is a carbon dioxide test?

A carbon dioxide test helps to determine the carbon dioxide amount in your blood. Your body develops carbon dioxide, which is a waste byproduct of metabolism. Metabolism is a chemical process in which your body converts food into energy when needed.
Carbon dioxide is an odorless, colorless gas that carries in your blood and transfers to your lungs. Each day you exhale carbon dioxide and inhale oxygen several times in your body. Most carbon dioxide in your body is present in the form of bicarbonate. Bicarbonate is an electrolyte that helps to maintain pH (acid-base) balance. High or low carbon dioxide levels may indicate health problems.

What is the purpose of this test?

A carbon dioxide test measures all forms of carbon dioxide in your blood, including bicarbonate, carbonic acid, and dissolved CO2. This test provides an approximate bicarbonate amount. A CO2 blood test often conducted with a series of tests known as an electrolyte panel. This test is a routine test to diagnose or monitor your health conditions related to electrolyte disorders, such as diseases of the kidneys, lungs, or liver, and increased blood pressure. Carbon dioxide may use to:
 

• Diagnose conditions if you are at risk of liver, digestive, or lung disease. It is because your body utilizes carbon dioxide to maintain acid-base balance. These diseases have a connection when changes happen in the bicarbonate levels.
• Monitor how well treatment is going if you have a disease linked with bicarbonate levels. These may include Cushing or kidney disease.
• Observe the side effects of medicines such as metformin. It may lead to acidosis. Acidosis develops due to the deposition of acid or loss of bicarbonate from the body.

When do I need to take this test?

You may need a carbon dioxide test if you see symptoms of an electrolyte disorder. Signs and symptoms include
 

• Weakness
• Fatigue
• Vomiting and diarrhea for a long time.
• Difficulty breathing
• Confusion

If you see the above symptoms, you can order this test.

What is the procedure for this test?

A carbon dioxide test often performs with a blood sample. The following are the steps for this test after visiting the laboratory.
 

• Sit in front of your provider. Be relaxed and stay in a fixed position. It is difficult for your provider to collect a blood sample if you do the muscle movement.
• Remove the portion of your cloth from the arm.
• A small needle will inject into a vein in your arm.
• A small amount of blood will collect in a test tube.
• Blood samples will store in the laboratory for examination of an allergy.
• You can go home for regular activities.
• This test usually takes five minutes.

How do I need to prepare for this test?

Your provider will guide you about special preparation for the carbon dioxide blood test. You may need to avoid specific medicines before the test. Do not stop medications before consulting with a professional healthcare provider. If your provider asks for additional blood tests, you may need to fast for several hours before the test. 

Are there any risks involved in this test?

A carbon dioxide test does not have high risks when you give a blood sample. Veins differ from person to person. Some people or children may have difficulty providing a blood sample compared to others. You may experience low risks when the needle injects into your vein. These risks include
 

• Bruising
• Extreme Bleeding
• Slight pain
• Infection
• Hematoma (Deposition of blood under the skin)

What do the test results indicate?

The carbon dioxide test results depend on many factors, such as age, gender, and medical history. The test results may also slightly differ among laboratories. It is because each lab may use different methods for examination.
The reference range for carbon dioxide is about 23 to 30 milliequivalents per liter (mEq/L). Abnormal results may show that your body does not maintain enough acid-base balance. It is because your kidneys or lungs contain a disorder to remove carbon dioxide. You may also have an electrolyte imbalance in your body. Various conditions lead to these problems.
Your healthcare provider will understand your results when you take a carbon dioxide test.

Low carbon dioxide levels may indicate the following conditions:
 

• Addison disease (adrenal gland disorders)
• Metabolic acidosis - The buildup of large acids in your blood may occur due to kidney or liver disease or diarrhea for a long time.
• Lactic acidosis (deposition of lactic acid in the blood)
• Respiratory alkalosis - A condition of low acid levels in your blood may happen due to lung or breathing disorders, such as increased breathing.
• Ketoacidosis (Complications of type 1 and type 2 diabetes)

 
 High carbon dioxide levels may show the following conditions:
 

• Kidney failure or damage
• Metabolic alkalosis - Deposition of a large bicarbonate amount in your blood may occur due to vomiting, dehydration, and anorexia (eating disorders).
• Cushing disease - Cushing syndrome disorder in which your pituitary gland releases high adrenocorticotropic hormone (ACTH). 
• Hyperaldosteronism (adrenal gland disorder)
• Lung disease

If you have higher carbon dioxide levels, you may need oxygen therapy and some medications to maintain carbon dioxide levels in the blood. You can eat more fruits and vegetables and fewer meats, eggs, and cereals for low carbon dioxide levels. Sodium bicarbonate and sodium citrate pills may also control metabolic acidosis.
If you want to take treatment for high or low carbon dioxide levels, consult a healthcare professional.

What factors may affect the test results?

If you have abnormal carbon dioxide test results, you don't always have medical conditions that require treatment. Specific medicines may reduce or raise your bicarbonate levels in the blood. 

What additional tests do I need along with a carbon dioxide blood test?

Your healthcare provider may ask for an electrolyte panel test to measure other minerals, such as sodium, potassium, and chloride amounts.

Get information about more laboratory tests from here.