Carbon Dioxide (CO2) Test
The carbon dioxide test, also listed as CO2 content or bicarbonate, measures the level of carbon dioxide in a blood sample. It is a marker clinicians use in evaluating the body's acid-base balance, read together with other blood chemistry results.
About this test
Carbon dioxide in the blood is mostly present as bicarbonate, and Quest lists this same test under the names CO2 content, HCO3 and bicarbonate. The result is a single value that reflects the body's acid-base chemistry at the time of the draw, measured from a blood sample using spectrophotometry.
Quest describes this measurement as used in evaluating a range of conditions connected to changes in acid-base balance. Because a shift in this value can come from many different sources, a clinician reads it together with other basic chemistry results rather than by itself.
Test details
| Quest code | 310 |
|---|---|
| Methodology | Spectrophotometry |
| Sample type | 1 full unopened spun gel barrier tube |
| Collection | Quest patient service center |
Reference range
20-32 mmol/L
Reference ranges are general guidance. The range printed on your own laboratory report is the one that applies to your result.
Related tests and panels
Measures alkaline phosphatase, an enzyme related to liver, bile duct and certain…
Measures amylase, an enzyme from the pancreas and salivary glands associated…
Measures total bile acids, a marker used to evaluate liver function and bile flow.
Quest resources
Additional details
What this test looks at
The test reports the concentration of carbon dioxide in the blood, which Quest also lists under the names CO2 content, HCO3 and bicarbonate — these all refer to the same measurement rather than separate tests.
Order online and a physician order is included — no doctor's visit and no insurance needed. Your sample is collected at a Quest Diagnostics patient service center.
Laboratory results should always be interpreted by a licensed clinician who knows your health history. This page is information about a test, not medical advice.
Frequently asked questions
What does this test measure?
It measures the concentration of carbon dioxide, mostly present as bicarbonate, in a blood sample analyzed by spectrophotometry.
How is the sample collected?
The test uses a blood sample collected in a specific tube (a full, unopened spun gel barrier tube), drawn at a Quest Diagnostics patient service center.
Do I need to prepare for this test?
No preparation instructions are listed for this test, though people follow any instructions their ordering clinician provides.
Is CO2 the same as bicarbonate?
Yes. Quest lists this test under several names — CO2 content, HCO3 and bicarbonate — and they all refer to the same carbon dioxide measurement.
What does a Carbon Dioxide test cost without insurance?
$15. Celio Health's price is a flat cash price and insurance is never billed: the required physician's order is included.