carbon monoxide testing

13 May


Your next patient is a 30 yo who is brought in by EMS after being pulled out of a burning apartment building.  They’re awake, but complaining of a headache, and of course, you’re worried about carbon monoxide. 

How do you want to test for this, and what number/percent are you ok with?



2 most commonly found options in the ED: co-oximetry & serum carboxyhemoglobin testing


noninvasive pulse co-oximetry (similar to your pulse-ox, but for CO)

  • via some small studies: mean absolute error of 3.15% (vs. serum testing)
  • frame of reference: mean absolute variation between various blood gas analyzers – 2.4%


carboxyhemoglobin testing

  • relationship between COHb levels and poisoning severity is generally poor
  • no clinically relevant difference between arterial and venous COHb levels
    • 95% of samples range between 2.4% and -2.1% of each other
  • COHb level > 3% in non-smokers or > 10% in smokers suggests an abnormal CO exposure


References: EBMedicine article, picture

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: