Skip to content

Carbon Monoxide (CO) Test

Make an Appointment

Our team is here to help you make an appointment with the specialists that you need.

Carbon Monoxide (CO) Test

Test Overview

A carbon monoxide blood test is used to detect carbon monoxide poisoning. Poisoning can happen if you breathe air that contains too much carbon monoxide (CO). This gas has no color, odor, or taste, so you can't tell when you are breathing it. The test measures the amount of hemoglobin in your blood that has bonded with carbon monoxide.

Carbon monoxide can come from any source that burns fuel. Common sources are cars, fireplaces, powerboats, woodstoves, kerosene space heaters, charcoal grills, and gas appliances such as water heaters and ovens. These things usually cause no problems. But if they are not used or installed properly, carbon monoxide may build up in an enclosed space.

When you inhale carbon monoxide, it replaces the oxygen that is normally carried by the hemoglobin in your red blood cells. As a result, your brain and other tissues get less oxygen. This can cause serious symptoms or death.

Why It Is Done

This test may be done if you have been exposed to carbon monoxide or if you have unexplained symptoms, such as:

  • Headache, dizziness, or vision problems.
  • Nausea or vomiting.
  • Muscle weakness.
  • Confusion or trouble thinking.
  • Extreme sleepiness.

How To Prepare

Do not smoke before you have this test. Tobacco smoke contains carbon monoxide.

How It Is Done

A health professional uses a needle to take a blood sample, usually from the arm.

Watch

How It Feels

When a blood sample is taken, you may feel nothing at all from the needle. Or you might feel a quick sting or pinch.

Risks

There is very little chance of having a problem from this test. When a blood sample is taken, a small bruise may form at the site.

Credits

Current as of: May 14, 2023

Author: Healthwise Staff
Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

This information does not replace the advice of a doctor. Healthwise, Incorporated, disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. Learn how we develop our content.