Test Code CO2 Carbon Dioxide, Serum
Additional Codes
Epic: LAB55
Specimen Required
Specimen Type: Serum
Collection Container/Type
Preferred: Serum gel
Acceptable: Green top (Lithium heparin)
Submission Container/Tube: Plastic vial
Specimen Volume: 3 mL
Collection Instructions:
- Centrifuge and separate cells after clot formation and within 4 hours of collection.
- Keep tightly capped to prevent evaporation of CO2.
Specimen Minimum Volume
0.10 mL
Specimen Stability
Room temperature: 24 hours
Refrigerated: 7 days
Frozen: 2 weeks
Reference Range
22 - 29 mEg/L
Rejection Due To
Unlabeled, mislabeled, wrong tube type, QNS, severely hemolyzed samples
Report Available
Same day
Clinical Significance
Carbon dioxide and phosphoenyl pyruvate (PEP) are converted to oxalacetate and phosphate catalyzed by PEP carboxylase. Oxalacetate is then reduced to malate while NADH is oxidized. The resulting decrease in absorbance is measured at 404nm and is proportional to the CO2 content in the sample.
Method Name
PEP Carboxylase
LOINC
2028-9
Day(s) Performed
Daily