Carbon Monoxide (CO)
How It Feels
The blood sample is taken from a vein in
your arm. An elastic band is wrapped around your upper arm. It may feel tight.
You may feel nothing at all from the needle, or you may feel a quick sting or
There is very little chance of a
problem from having a blood sample taken from a vein.
- You may get a small bruise at the site. You
can lower the chance of bruising by keeping pressure on the site for several
- In rare cases, the vein may become swollen after the blood
sample is taken. This problem is called phlebitis. A warm compress can be used
several times a day to treat this.
- Ongoing bleeding can be a
problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and
other blood-thinning medicines can make bleeding more likely. If you have
bleeding or clotting problems, or if you take blood-thinning medicine, tell
your doctor before your blood sample is taken.
A carbon monoxide blood test is used to
poisoning from breathing carbon monoxide (CO), a
colorless, odorless, poisonous gas. The test measures the amount of hemoglobin
that has bonded with carbon monoxide. This is also called the
Carbon monoxide results are reported as
a percentage: The amount of carbon monoxide bound to hemoglobin is divided by
the total amount of hemoglobin (and then multiplied by 100). The higher the
percentage, the greater the risk of having symptoms of carbon monoxide
poisoning. With values below 10%, a person may not have any symptoms of
The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.