co2 reading from a blood draw

[mich5]

I had a regular blood draw, but they took several vials, and a co2 result showed up in the results. Is this an accurate number? People here talk about a blood gas test to get an accurate co2 reading, but I don't know what that is. Is it a special blood test or just a regular blood draw that is processed differently?

 

[lgelb]

An arterial blood gas where blood is drawn from the radial artery, usually, is the gold standard, though it's only reflecting that particular time, but the blood draw from the vein (venipuncture) may be directional in terms of which way things are going.

There are also portable sensors that can measure CO2 noninvasively. If anyone has one at your clinic, it would probably be the RT.

If we are talking about using CO2 levels to assess the need to adjust BiPAP settings, that more often should be based on how you feel/breathe and what the data on the machine show. As a prognostic factor, you aren't going to take them often enough to really be helpful, even if the numbers could really be used that way.

 

[KarenNWendyn]

CO2 results on a chemistry panel from a venous blood sample are notoriously inaccurate. The most accurate way to measure CO2 is with an arterial blood gas.

I co-owned a chemistry analyzer machine in the office where I used to work. The techs had a heck of a time calibrating the CO2. It got to the point where we basically ignored that particular test (it was part of a 14 item lab panel).

 

[JimInVA]

Darcey had one of those tests, once, very early on. Always wondered why it was never repeated, again, later. Thanks, for the follow-up comments!


Jim