Carbon Dioxide (CO2) in Blood

Carbon Dioxide (CO2) in Blood: An Overview

Carbon dioxide (CO2) is an important component of human blood and is an essential part of the body's chemistry. It has many functions in the body, such as helping to regulate blood pH, maintain a healthy blood pressure, and assisting in the release of oxygen from the bloodstream. It is also involved in the metabolism of carbohydrates and proteins. In this article, we'll discuss everything you need to know about CO2 in blood, including what it is, how it's measured, its uses and functions, risk factors, and when and why it needs to be monitored.

Preparation and Procedure

CO2 in the blood is measured via a process called arterial blood gas (ABG) analysis. This involves the collection of a sample of blood from an artery (usually the radial or femoral artery in the arm or leg). The sample is then analyzed in the laboratory to determine the CO2 level.

Types of CO2 in Blood

CO2 in the blood can be classified into two main types: dissolved CO2 (bicarbonate) and uncombined CO2 (carbon dioxide). Dissolved CO2 is responsible for the regulation of blood pH, whereas uncombined CO2 is responsible for the transport of oxygen from the lungs to the cells. Both forms of carbon dioxide are essential for normal functioning of the body.

Uses and Functions

  • Regulate blood pH: CO2 helps to regulate the pH of the blood by combining with water to form carbonic acid, which helps maintain the optimum pH level.
  • Maintain a healthy blood pressure: CO2 helps to maintain a healthy blood pressure by maintaining a balance between the pressure of the oxygen and carbon dioxide in the bloodstream.
  • Release of oxygen from the bloodstream: CO2 helps to release oxygen from the bloodstream, allowing it to enter cells and be used by the body.
  • Help in the metabolism of carbohydrates and proteins: CO2 helps in the metabolism of carbohydrates and proteins in the body.


High levels of CO2 in the blood can have serious health implications. Too much CO2 can compromise the pH balance of the blood, leading to neurological symptoms such as confusion and fatigue. In cases of more severe imbalance, coma and even death can occur.

Why and When to Monitor CO2 Levels in Blood

CO2 levels in the blood should be monitored regularly for those who are at risk of developing respiratory or metabolic disorders. It is also important for those who are pregnant, as high levels of CO2 can put the baby at risk of developmental delays. In people with existing medical conditions, regular monitoring of CO2 levels can help to detect any changes in the body's chemistry and help identify any treatment that may be required.