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. You can treat this by using a warm compress several times a day.
Bleeding can be a
problem for people who have bleeding disorders or take blood-thinning medicines such as aspirin or warfarin (Coumadin). 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 detect
carbon monoxide poisoning. Poisoning can happen if you breathe air that contains too much carbon monoxide. The test measures the amount of hemoglobin
that has bonded with carbon monoxide. This is called the
The results are reported as
a percentage. They show the amount of carbon monoxide bound to hemoglobin divided by
the total amount of hemoglobin (multiplied by 100). The higher the
percentage, the greater the risk of having symptoms of carbon monoxide
poisoning . A person with values below 10% may not have any symptoms.
These numbers are just a guide. The range for "normal" varies from lab to lab. Your lab may have a different range. Your lab report should show what range your lab uses for "normal." Also, your doctor will evaluate your results based on your health and other factors. So a number that is outside the normal range here may still be normal for you.
Results are usually available right away.
People who don't smoke:
Less than 2% of total hemoglobin
People who smoke:
4%–8% of total hemoglobin