CO2 In Blood - Low, High And Normal Values
Tests & Procedures

CO2 In Blood – Low, High And Normal Values

Carbon dioxide (CO2) is a colorless and odorless gas that is considered a waste product of your body. It is carried by your blood to your lungs so that if you breathe out, you release this gas and in exchange, breathe in oxygen. And yes, your body does this process all the time, that is why it is also important to know the normal CO2 levels. Normal CO2 levels in the blood may be indicative of your entire well-being.

What Is Co2 In Blood And How Is It Measured?

It is normal for your body to produce a waste product that has no color or odor, typically referred to as gas, known as carbon dioxide. Unconsciously, your blood carries CO2 to your lungs as you exhale. The CO2 in your blood is mostly comprised of bicarbonate, a form of CO2 that maintains your body’s acids and bases.

A healthy individual usually has normal levels of CO2 in the blood. If your doctor is in doubt of your CO2 levels, you may be required to undergo a carbon dioxide blood test. Other names of this test include CO2 content, bicarbonate blood test, total CO2, TC02, HC03, and CO2 test serum.

This test can measure the levels of carbon dioxide in your blood. This test is usually done if you have difficulty breathing, as well as if you feel disoriented and confused. Your healthcare provider may also require this if you have digestive, liver, or lung disease. This is because CO2 is used by your body to balance your pH levels and electrolytes. And a change in your CO2 levels might be indicative of these diseases.

What Are The Normal Co2 Levels?

The normal levels of CO2 in your blood may depend upon various factors such as sex, age, and medical history. Sometimes, the normal levels of CO2 may also depend upon the range set by a certain laboratory, how the test is administered, and the kind of medication an individual is taking.

The normal range for CO2 in your blood is 23 to 29 mEq/L. According to age, the normal CO2 level of an individual aging 18 to 59 years old is from 23 to 29 mEq/L. For 60 to 89 years old, it is from 23 to 31 mEq/L. And for 90 years and above, it is from 20 to 29 mEq/L. According to sex, men usually have one mEq/L higher than women.

Normal Co2 Levels For Adults By Age

Age Group Normal Co2 Levels
18-59 years 23 to 29 mEq/L
60-89 years 23 to 31 mEq/L
Above 90 years 20 to 29 mEq/L

What Do Low Co2 Levels In Blood Mean?

Low levels of CO2 may mean that you have a condition called metabolic acidosis. This occurs when acids and bases in your blood are not balanced. Your body might not have a sufficient amount of base to normalize the acid in your body. Your body may be making too much acid. Or maybe, you cannot get rid of excess acid in your body.

What Causes Low Co2 Levels In Blood?

Common causes of low CO2 levels are

How Do You Treat Low Co2 Levels?

Usually, a person who has low levels of CO2 may be suffering from metabolic acidosis. There are various types of metabolic acidosis and have their own treatments. Acidosis due to kidney failure can be treated with sodium citrate. If it is due to hyperchloremic acidosis, a person may be given oral sodium bicarbonate.

If a person is diabetic, he may have IV fluids and insulin at the same time. Depending on the cause of lactic acidosis, a person may be given IV fluids, bicarbonate supplements, antibiotics, or oxygen.

What Does High Co2 In Blood Mean?

High levels of CO2 may mean that you have a condition called metabolic alkalosis. It occurs when your body has an excess base or loses too much acid.

What Causes High Co2 Levels?

Common causes of high CO2 levels are

How To Lower High Co2 Levels In Blood?

People with high CO2 levels are usually indicative of metabolic alkalosis. The treatment varies depending on the kind of alkalosis suffered. If it is chloride-responsive, then a change in lifestyle might suffice, such as increasing the consumption of salt or sodium chloride. Other healthcare providers may give you a saline solution or an IV. If it is chloride-resistant, then you may be required to increase your potassium levels, such as by receiving potassium chloride and taking pills with potassium chloride.


If your result does not indicate normal CO2 levels, maybe due to acidosis or alkalosis, your doctor will determine the cause of the abnormalities and suggest the appropriate treatment for your condition. You can maintain normal CO2 levels in blood upon the proper treatment, including medications, lifestyle changes, and surgery.

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