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Test Code 155 Carbon Dioxide (CO2)

Additional Codes


PowerChart: Carbon Dioxide Level

MA Cerner: Carbon Dioxide

Specimen Requirement

0.5 mL serum or plasma is required.

Additional Specimen Collection Information

Collect blood in a lithium heparin, green-top or red-top tube. PST and SST (gel tubes) are acceptable. Serum or plasma should be separated from contact with the cells within 2 hours of collection. Specimens not centrifuged within 4 hours of collection may be rejected. Refrigerate the specimen if unable to assay within 8 hours of collection. Hemolyzed specimens are not acceptable. Samples with >3+ lipemia must be cleared prior to analysis.

Useful For

Carbon dioxide levels are important is assessing metabolic acidosis and hyperventilation.


Testing is performed Monday through Sunday.

Routine: Typically completed within 4 hours after the specimen arrives at the testing site.

Expedite: Typically completed within 1 hour after the specimen arrives at the testing site.

STAT: Typically completed within 30 minutes after the specimen arrives at the testing site.

CPT Code Information

82374 Chemistry: Carbon dioxide (bicarbonate)

LOINC Code Information

2028-9 Carbon Dioxide, Total [Moles/Volume] In Serum Or Plasma

Test Method

MercyOne DBQ: Rate pH Change, CO2 Electrodes; Beckman DXC880i

Mercy DV, MQ: Ionic Strength Measurements; iSTAT

MA: Enzymatic Rate Method; Roche Cobas 6000

Reference Values

22-32 meq/L

  • Critical Value:
    • Low: < 10 meq/L
    • High: > 40 meq/L