Sign in →

Test Code CO2 Carbon Dioxide, Total

Clinical System Name

Carbon Dioxide, Total


Bicarbonate (HCO3) Blood
CO2 (Carbon Dioxide)
CO2 measured
HCO 3 - Blood

Sample Requirements

Specimen:  Whole Blood

Container(s): Gold SST, Dark Green/Sodium Heparin, Red, Gold Microtainer, Lt. Green/Li Heparin Microtainer

Preferred Vol: 1.0 mL

Minimum Vol: 0.5 mL


Note: Red or Gold SST tubes acceptable but not preferred. Use Dark Green/Sodium Heparin or Lt. Green/Li Heparin Microtainer for fastest results. Method is affected by exposure to air (decreases CO2 value), prolonged exposure to RBC's (increases value), and EDTA. Not affected by moderate hemolysis, icterus, or any type of heparin (Na, Li or ammon). The TCO2 test should not be cancelled as a duplicate because it is not included in our blood gas panels.

Processing Instructions

Reject due to: Age of Specimen

Spin: Y

Aliquot: Y

Temp: 2-8oC

Storage Location:  Core 5 Chemistry Refrigerator


Off-site collection: Spin blood, remove plasma or serum from cells, and refrigerate at 2-8oC. Deliver to Lab within 24 hours.




Specimen Type Temperature Time
Serum or Plasma RT

24 H

Serum or Plasma 2-8oC

 3 D

Serum or Plasma -20oC or -70oC

 30 D



STAT Performed TAT
Y 24/7 1 H


Performing Laboratory

Seattle Children's Laboratory    


Department:  Chemistry - Core

Phone Number: 206-987-2617

Reference Range

All Ages:


18 - 27 mEq/L



Method: Enzymatic Endpoint by Vitros 4600

Analytical Volume: 0.05 mL




CPT Codes


Critical Values

≤ 10 mEq/L

≥ 40 mEq/L